Tkool Electronics

AD603IntroductionTheAD603isalownoise,voltage-controlledamplifierforuseinRFandIFAGCsystems.Itprovidesaccurate,pin-selectablegainsof11dBto+31dBwithabandwidthof90MHzor+9dBto51+dBwithabandwidthof9MHz.Anyintermediategainrangemaybearrangedusingoneexternalresistor.Theinputreferrednoisespectraldensityisonly1.3nV/Hz,andpowerconsumptionis125mWattherecommended5Vsupplies.CatalogAD603IntroductionAD603FeaturesAD603PinConfigurationandFunctionsAD603FunctionalBlockDiagramAD603WorkingModesAD603FunctionalEquivalentsAD603PackageOutlineAD603TypicalApplicationAD603ApplicationsAD603ApplicationNoteComponentDatasheetFAQOrdering&QuantityAD603FeaturesLinear-in-dBgaincontrolPin-programmablegainranges:11dBto+31dBwith90MHzbandwidth9dBto51dBwith9MHzbandwidthAnyintermediaterange,forexample,1dBto+41dBwith30MHzbandwidthBandwidthindependentofthevariablegain1.3nV/Hzinputnoisespectraldensity60.5dBtypicalgainaccuracyAD603PinConfigurationandFunctionsAD603FunctionalBlockDiagramFigure1AD603functionalblockdiagramItisnotdifficulttofindthatitisdifferentfromAD600inthat:thefixedgainamplifieritusescanchangethegainvalue.ThegainGFisdeterminedbytheconnectionformofVOUTandFDBK.WhenVOUTandFDBKareshort-circuited,GF=31.07dB;whenitisopen,GF=51.07dB;connectresistorREXTbetweenVOUTandFDBKtosetGFAnyvaluebetween31.07dB~51.07dB.However,thegainaccuracyinthismodeisreduced.Whentheexternalresistanceisabout2K,theerroristhelargest.IfanappropriateresistorisconnectedbetweenVOUTandCOMM,thegaincanbeincreased,upto60dB.AD603WorkingModesAD603hasthreeworkingmodes:Mode1:Short-circuitVOUTandFDBK,thisconnectioncanobtainthemaximumbandwidth-90MHz,andthegainrangeis-11.07dB~+31.07dB.AsshowninFigure2.Figure2ShortconnectionbetweenVOUTandFDBKMode2:ConnectaresistorREXTbetweenVOUTandFDBK,anda5.6pFcapacitorbetweenFDBKandCOMMasfrequencycompensation.Accordingtotherelationalexpressionoftheamplifier,selectingtheappropriateREXTvaluecanobtaindifferentgainrangevalues.WhenREXT=2.15Kohms,thegainrangeis:-1dB~+41dB.AsshowninFigure3.Figure3VOUTandFDBKaccessresistanceREXTMode3:OpenacircuitbetweenVOUTandFDBK,andconnectan18pFcapacitorbetweenVOUTandCOMMtoextendthefrequencyresponserange.Thismodeisahighgainmodewithagainrangeof8.93dB~51.07dBandabandwidthof9MHz.AsshowninFigure4.Figure4HighgainmodeIntheabovethreemodes,therelationshipbetweengainGFandcontrolvoltageVGisshowninFigure5.Figure5TherelationshipbetweengainGFandcontrolvoltageVGWhenVGisintherangeof-500mV~+500mVat40dB/V(thatis25mV/dB,whichisdifferentfromAD600s32mV/dB)forlineargaincontrol,therelationshipbetweengainG(dB)andVG(V)is:G=40VG+Goi(I=1,2,3),whereVG=VPOS-VNEG.G0iisthedifferentgainconstantsinthreemodes.Mode1:GOi=10dB;Mode2:GOi=10dB~30dB(determinedbytheexternalresistorREXT);Mode3:GOi=30dB.WhenthecontrolvoltageVGisoutside-500mV~+500mV,thegainGandVGnolongersatisfythelinearrelationship.WhenVG=-526mV,thegainisG=GF-42.14,whenVG=+526,thegainisG=GF.AD603TypicalApplicationFigure6AD603typicalapplicationcircuitFigure6isatwo-stageAD603amplifiercircuitwithautomaticgaincontrol.Inthefigure,Q1andR8formadetectortodetectchangesintheamplitudeoftheoutputsignal.TheautomaticgaincontrolvoltageVAGCisformedbyCAV,thedifferencebetweenthecurrentQ2andthecollectorcurrentofQ1flowingintothecapacitorCAV,anditsmagnitudechangeswiththeamplitudeoftheoutputsignalofA2,whichmakesitaddedtoA1andA2amplifier1.TheautomaticgaincontrolvoltageVAGCofthepinchangeswiththeoutputsignalamplitudechange,soastoachievethepurposeofautomaticallyadjustingtheamplifiergain.AD603FunctionalEquivalentsAD603PackageOutlineAD603ApplicationsRF/IFAGCamplifiersVideogaincontrolsA/DrangeextensionsSignalmeasurementsAD603ApplicationNote(1)Thepowersupplyvoltageshouldgenerallybeselectedas5V,andthemaximumshouldnotexceed7.5V.(2)Inthecaseof5Vpowersupply,theeffectivevalueoftheratedvoltageappliedtotheinputterminalVINPshouldbe1V,thepeakvalueis1.4V,andthemaximumshouldnotexceed2V.Ifyouwanttoexpandthemeasurementrange,youshouldaddalevelofattenuationinfrontofAD603.Inthisway,thetypicalvalueofthepeakoutputvoltagecanreach3.0V.Therefore,itisusuallynecessarytoaddafirstlevelofamplificationafterAD603toconnecttotheA/Dconverter.(3)Thevoltageappliedtothevoltagecontrolterminalmustbeverystable,otherwisethegainwillbeunstable,whichwillincreasethenoiseoftheamplifiedsignal.(4)Thesignalmustbedirectlyconnectedtopin4oftheamplifier,otherwisetheaccuracyoftheamplifierwillbereducedduetothelargeimpedance.ComponentDatasheetAD603DatasheetFAQWhatisAD603?AD603isalow-noise,voltage-controlledamplifierforradiofrequency(RF)andintermediatefrequency(IF)automaticgaincontrol(AGC)systems.Itprovidesprecisepin-selectablegain,withagainrangeof-11dBto+31dBat90MHzbandwidth,andagainrangeof+9dBto+51dBat9MHzbandwidth.Anyintermediategainrangecanbeobtainedwithanexternalresistor.Thenoisespectraldensityreferredtotheinputisonly1.3nV/Hz,andthepowerconsumptionis125mWwhenusingtherecommended5Vpowersupply.WhataretheproblemsthatneedtobepaidattentiontowhenusingAD603?Thevoltagecannotbetoohigh.Generally,thevoltageisplusorminus5V,andthemaximumvoltagecannotexceedplusorminus7.5V.Theoutputvoltagecannotexceed2V.Howtosolvetheself-oscillationproblemofAD603?Forhigh-frequencyoperationalamplifiers,thefollowingpointsarethebasicwaystosolveself-excitation.Thepowersupplyisstableandnoripple.Theelectricalconnectionwiresareasshortaspossible.Thead603circuitshouldbefarawayfromthepowercircuit,especiallyawayfromthetransformer.Thepowertransformerandthecircuitboardofad603shouldbeshieldedwithametalboxandgroundedifpossible.Onepointisveryimportant.Foropamps,toolargemagnificationcaneasilycauseself-excitation,soreducethemagnificationasmuchaspossibleandminimizethenumberofmagnificationlevels(generallynotgreaterthan4).Reverseamplificationcansuppressself-excitationinmulti-stageamplification.Ifyouwanttoconnecttothepoweramplifierandthenamplify,itisbesttousetwopowersupplies,andthecircuitshouldbeconnectedtothesameground.WhatisthedifferencebetweenAD603AQandAD603AR?Theirdifferencesareinmodel,Temperature,Package.AD603AQ-40Cto+85C8-LeadCERDIPAD603AR-40Cto+85C8-LeadSOIC_NAfterinputtinganACsignalandbeingamplifiedbyAD603,whydoestheoutputcontainaDCsignal?HowtoeliminatetheDCsignal?WhentheDCblockingcapacitorisnotused,thebiasvoltageoftheinputcircuitneedstobeadjustedforcompensation.IftheDCvoltageoftheACsignalisnotfixed,onlyaDCblockingcapacitorcanbeused,ortheaveragevaluecanbeusedtoeliminateitaftersamplingthenumber.

BYM11-1000-E3/96-VISHAY

AD603IntroductionTheAD603isalownoise,voltage-controlledamplifierforuseinRFandIFAGCsystems.Itprovidesaccurate,pin-selectablegainsof11dBto+31dBwithabandwidthof90MHzor+9dBto51+dBwithabandwidthof9MHz.Anyintermediategainrangemaybearrangedusingoneexternalresistor.Theinputreferrednoisespectraldensityisonly1.3nV/Hz,andpowerconsumptionis125mWattherecommended5Vsupplies.CatalogAD603IntroductionAD603FeaturesAD603PinConfigurationandFunctionsAD603FunctionalBlockDiagramAD603WorkingModesAD603FunctionalEquivalentsAD603PackageOutlineAD603TypicalApplicationAD603ApplicationsAD603ApplicationNoteComponentDatasheetFAQOrdering&QuantityAD603FeaturesLinear-in-dBgaincontrolPin-programmablegainranges:11dBto+31dBwith90MHzbandwidth9dBto51dBwith9MHzbandwidthAnyintermediaterange,forexample,1dBto+41dBwith30MHzbandwidthBandwidthindependentofthevariablegain1.3nV/Hzinputnoisespectraldensity60.5dBtypicalgainaccuracyAD603PinConfigurationandFunctionsAD603FunctionalBlockDiagramFigure1AD603functionalblockdiagramItisnotdifficulttofindthatitisdifferentfromAD600inthat:thefixedgainamplifieritusescanchangethegainvalue.ThegainGFisdeterminedbytheconnectionformofVOUTandFDBK.WhenVOUTandFDBKareshort-circuited,GF=31.07dB;whenitisopen,GF=51.07dB;connectresistorREXTbetweenVOUTandFDBKtosetGFAnyvaluebetween31.07dB~51.07dB.However,thegainaccuracyinthismodeisreduced.Whentheexternalresistanceisabout2K,theerroristhelargest.IfanappropriateresistorisconnectedbetweenVOUTandCOMM,thegaincanbeincreased,upto60dB.AD603WorkingModesAD603hasthreeworkingmodes:Mode1:Short-circuitVOUTandFDBK,thisconnectioncanobtainthemaximumbandwidth-90MHz,andthegainrangeis-11.07dB~+31.07dB.AsshowninFigure2.Figure2ShortconnectionbetweenVOUTandFDBKMode2:ConnectaresistorREXTbetweenVOUTandFDBK,anda5.6pFcapacitorbetweenFDBKandCOMMasfrequencycompensation.Accordingtotherelationalexpressionoftheamplifier,selectingtheappropriateREXTvaluecanobtaindifferentgainrangevalues.WhenREXT=2.15Kohms,thegainrangeis:-1dB~+41dB.AsshowninFigure3.Figure3VOUTandFDBKaccessresistanceREXTMode3:OpenacircuitbetweenVOUTandFDBK,andconnectan18pFcapacitorbetweenVOUTandCOMMtoextendthefrequencyresponserange.Thismodeisahighgainmodewithagainrangeof8.93dB~51.07dBandabandwidthof9MHz.AsshowninFigure4.Figure4HighgainmodeIntheabovethreemodes,therelationshipbetweengainGFandcontrolvoltageVGisshowninFigure5.Figure5TherelationshipbetweengainGFandcontrolvoltageVGWhenVGisintherangeof-500mV~+500mVat40dB/V(thatis25mV/dB,whichisdifferentfromAD600s32mV/dB)forlineargaincontrol,therelationshipbetweengainG(dB)andVG(V)is:G=40VG+Goi(I=1,2,3),whereVG=VPOS-VNEG.G0iisthedifferentgainconstantsinthreemodes.Mode1:GOi=10dB;Mode2:GOi=10dB~30dB(determinedbytheexternalresistorREXT);Mode3:GOi=30dB.WhenthecontrolvoltageVGisoutside-500mV~+500mV,thegainGandVGnolongersatisfythelinearrelationship.WhenVG=-526mV,thegainisG=GF-42.14,whenVG=+526,thegainisG=GF.AD603TypicalApplicationFigure6AD603typicalapplicationcircuitFigure6isatwo-stageAD603amplifiercircuitwithautomaticgaincontrol.Inthefigure,Q1andR8formadetectortodetectchangesintheamplitudeoftheoutputsignal.TheautomaticgaincontrolvoltageVAGCisformedbyCAV,thedifferencebetweenthecurrentQ2andthecollectorcurrentofQ1flowingintothecapacitorCAV,anditsmagnitudechangeswiththeamplitudeoftheoutputsignalofA2,whichmakesitaddedtoA1andA2amplifier1.TheautomaticgaincontrolvoltageVAGCofthepinchangeswiththeoutputsignalamplitudechange,soastoachievethepurposeofautomaticallyadjustingtheamplifiergain.AD603FunctionalEquivalentsAD603PackageOutlineAD603ApplicationsRF/IFAGCamplifiersVideogaincontrolsA/DrangeextensionsSignalmeasurementsAD603ApplicationNote(1)Thepowersupplyvoltageshouldgenerallybeselectedas5V,andthemaximumshouldnotexceed7.5V.(2)Inthecaseof5Vpowersupply,theeffectivevalueoftheratedvoltageappliedtotheinputterminalVINPshouldbe1V,thepeakvalueis1.4V,andthemaximumshouldnotexceed2V.Ifyouwanttoexpandthemeasurementrange,youshouldaddalevelofattenuationinfrontofAD603.Inthisway,thetypicalvalueofthepeakoutputvoltagecanreach3.0V.Therefore,itisusuallynecessarytoaddafirstlevelofamplificationafterAD603toconnecttotheA/Dconverter.(3)Thevoltageappliedtothevoltagecontrolterminalmustbeverystable,otherwisethegainwillbeunstable,whichwillincreasethenoiseoftheamplifiedsignal.(4)Thesignalmustbedirectlyconnectedtopin4oftheamplifier,otherwisetheaccuracyoftheamplifierwillbereducedduetothelargeimpedance.ComponentDatasheetAD603DatasheetFAQWhatisAD603?AD603isalow-noise,voltage-controlledamplifierforradiofrequency(RF)andintermediatefrequency(IF)automaticgaincontrol(AGC)systems.Itprovidesprecisepin-selectablegain,withagainrangeof-11dBto+31dBat90MHzbandwidth,andagainrangeof+9dBto+51dBat9MHzbandwidth.Anyintermediategainrangecanbeobtainedwithanexternalresistor.Thenoisespectraldensityreferredtotheinputisonly1.3nV/Hz,andthepowerconsumptionis125mWwhenusingtherecommended5Vpowersupply.WhataretheproblemsthatneedtobepaidattentiontowhenusingAD603?Thevoltagecannotbetoohigh.Generally,thevoltageisplusorminus5V,andthemaximumvoltagecannotexceedplusorminus7.5V.Theoutputvoltagecannotexceed2V.Howtosolvetheself-oscillationproblemofAD603?Forhigh-frequencyoperationalamplifiers,thefollowingpointsarethebasicwaystosolveself-excitation.Thepowersupplyisstableandnoripple.Theelectricalconnectionwiresareasshortaspossible.Thead603circuitshouldbefarawayfromthepowercircuit,especiallyawayfromthetransformer.Thepowertransformerandthecircuitboardofad603shouldbeshieldedwithametalboxandgroundedifpossible.Onepointisveryimportant.Foropamps,toolargemagnificationcaneasilycauseself-excitation,soreducethemagnificationasmuchaspossibleandminimizethenumberofmagnificationlevels(generallynotgreaterthan4).Reverseamplificationcansuppressself-excitationinmulti-stageamplification.Ifyouwanttoconnecttothepoweramplifierandthenamplify,itisbesttousetwopowersupplies,andthecircuitshouldbeconnectedtothesameground.WhatisthedifferencebetweenAD603AQandAD603AR?Theirdifferencesareinmodel,Temperature,Package.AD603AQ-40Cto+85C8-LeadCERDIPAD603AR-40Cto+85C8-LeadSOIC_NAfterinputtinganACsignalandbeingamplifiedbyAD603,whydoestheoutputcontainaDCsignal?HowtoeliminatetheDCsignal?WhentheDCblockingcapacitorisnotused,thebiasvoltageoftheinputcircuitneedstobeadjustedforcompensation.IftheDCvoltageoftheACsignalisnotfixed,onlyaDCblockingcapacitorcanbeused,ortheaveragevaluecanbeusedtoeliminateitaftersamplingthenumber.

Introduction74LS04containssixindependentgateseachofwhichperformsthelogicINVERTfunction.Theoutputsignalsofthesixinvertersareoppositetotheinputsignals.CatalogIntroductionICircuitofRingOscillatorIISymmetricalSquare-waveOscillatorIIISimpleself-excitedMultivibratorIVCircuitofCrystalOscillatorandFrequencyDividerVFMWirelessMicrophoneFAQOrdering&QuantityICircuitofRingOscillatorFigure1.RingoscillatorTheexperimentalcircuitofanongateringself-excitedmultivibratorwithRCdelaycircuitisshowninthefigure.TheoscillationcircuitiscomposedofnongateIC1,IC2,IC3andtimingcircuitelementsRPandC.TherectangularwavesignalisoutputbyIC3.R1isaprotectiveresistortoavoiddamagetoIC3gatecircuitwhentimingcapacitorCisreversedischarged.NotgateIC4makestheoscillatoroutputrectangularwavewithbetterwaveform.Oscillationfrequencyestimationf1/2.3RCT2.3RCTheresistancevalueoftimingresistorisselectedintherangeof100-10002.ThetimingcapacitorChasalargevaluerange,fromseveralhundredpicofarads(pF)toseveralhundredmicrofarads,whichcanmaketheoscillationfrequencyrangefromseveralmegahertztoseveralhertz.Replacethetimingresistorwithapotentiometer(1.5k92),whichcancontinuouslyadjusttheoscillationfrequencyandhasalargercoverage.Thechipusedis74LS04.IISymmetricalSquare-waveOscillatorThefigureshowstheexperimentalcircuitofnon-gatesymmetricalsquare-waveself-excitedmultivibrator.Becausethecircuitissymmetrical,thedutycycleofoutputoscillationwaveformis1:1,whichissquarewave,soitiscalledsymmetricalsquarewaveoscillator.Intheoscillationcircuit,theoutputofnongateIC1iscoupledtotheinputofnongateIC2viaatimingcapacitorC2.Also,theIC2outputiscoupledtotheIC1inputviaC1.Twonongatesarecoupledwitheachotherthroughcapacitorstoformapositivefeedbackclosed-loopcircuit,whichcanproducesquare-waveoscillation.WhenR1=R4=R,C1=C2=C,theestimationformulaofoscillationfrequencyisasfollows:f1/RC.TheoscillationperiodTRC.Figure2.SymmetricalSquare-waveOscillatorIIISimpleself-excitedMultivibratorThefigureshowsasimplenongateself-excitedmultivibratorexperimentalcircuit.Itiscomposedofnon-gateoscillatorIC1,IC2,inverterIC3,redandgreenlight-emittingdiodesandpowersupplysystemGB.IC1andIC2aretheswitchinglinksoftheoscillator.R1andCtimingcircuitsproducedelaypositivefeedbacksignalstocontroltheswitchtoturnonandoffperiodically,sothatIC2outputsrectangularwave.TheinverterIC3makestheredandgreenLEDsandtheoscillatorflashalternately.Figure3.Simpleself-excitedmultivibratorIVCircuitofCrystalOscillatorandFrequencyDividerFigure4.CircuitofCrystaloscillatorandfrequencydividerVFMWirelessMicrophoneWirelessmicrophonesareavailableeverywhereonthemarket,buttheircircuitsareallmadeupofLCoscillatorsorquartzcrystaloscillatorcircuits.Asweallknow,theNANDgatehasthefunctionofmagnificationandphaseinversion.Therefore,aslongasthreeNANDgatesareconnected,aringoscillatorisformed.CoupledwiththeFMcircuit,itcanalsobemadeintoawirelessmicrophone.Figure5.FMwirelessmicrophone74LS04isaTTLintegratedcircuitwithsixsingle-inputNANDgates.Theauthorusesthreeofthemtomakeanoscillator.Whenthesupplyvoltageis5V,theoscillationfrequencyisabout90mhz.Whenthepowersupplyvoltagedecreases,thefrequencydecreases;whenthesupplyvoltageincreases,thefrequencyalsoincreases.Ofcourse,itsoscillationamplitudewillalsochange,buttheeffectisnotsignificant.Inthisway,theauthorusesthemethodofchangingthepowersupplyvoltagetochangethefrequency(thatis,toachievefrequencymodulation).ThespecificmethodistousetheoutputofBA328,anaudioamplifierintegratedcircuit,asitspowersupply.BA328isanamplifyingcircuitofrecordinghead.Whenitisusedfortapesignalcompensationandequalization,anRCseriesparallelnetworkshouldbeconnectedbetweenthefirstandthesecondpins,butitisusedforlinearamplification,soonlya100kw-130kwresistorisneeded.Thevoltageoftheoutputterminal(pin)ofBA328shouldbeequaltoone-halfofthevoltageofthepin(powersupply).Ifthepowersupplyvoltageis12V,thereshouldbea6Voutput.Ifitisnotcorrect,theresistanceshouldbeadjusted.Inaddition,the1kWresistorinthefigureisusedtoadjustthemagnification.Ifitisreduced,thegainwillbeincreased.Whenspeakingtoanelectretmicrophone,thevoltageattheoutput(PIN)canchangerapidlyfrom5.8vto6.2V.Thisvoltageissenttothefootof74LS04tomakeitgenerateFMsignal,whichisamplifiedandisolatedbythefourthNANDgateandsenttotheantenna.FAQWhatis74LS04?74LS04isamemberof74XXYYICseries.The74-seriesaredigitallogicintegratedcircuits.74LS04IChassixNOTgates.TheseNOTgatesperformInvertingfunction.HencenameHEXINVERTINGGATES.Whatisthefunctionofic74ls04?74LS04HexNOTGateIC.74LS04isa2inputquadruple8-bitNOTgateIC.InverterinlogicconvertersisanelectronicsdevicewhosebasicfunctionsaretoinverttheincominglogicweatheritisHIGHorLOW.TheyarealsoknownasNOTgates.Whatisahexinverter?Ahexinverterisatypeofanintegratedcircuitthatcontainssixinverters.Manysophisticateddigitaldevicesuseinverters,includingmultiplexers,decoders,andstatemachines.Aninvertercircuitsmainfunctionistooutputthevoltagerepresentingtheoppositeleveltoitsinput.WhyisNOTgatecalledaninverter?ANOTgate,oftencalledaninverter,isanicedigitallogicgatetostartwithbecauseithasonlyasingleinputwithsimplebehavior.ANOTgateperformslogicalnegationonitsinput.Inotherwords,iftheinputistrue,thentheoutputwillbefalse.Description74LS04containssixindependentgateseachofwhichperformsthelogicINVERTfunction.Theoutputsignalsofthesixinvertersareoppositetotheinputsignals.Theinvertercanreversethephaseoftheinputsignalby180degrees.Thiscircuitisusedinanalogcircuits,suchasaudioamplifier,clockoscillator,etc.Inverterisoftenusedinelectroniccircuitdesign.74LS04-HEXInverter-TruthTableExampleCatalogDescriptionCADModelsFeaturesApplicationPinoutCircuitDiagramPackageParametersElectricalCharacteristicsProductComplianceComponentDatasheetProductManufacturerFAQOrdering&QuantityCADModels74LS04FootprintFeaturesSupplyvoltagerange:+4.75Vto+5.25VMaximumsupplyvoltage:+7VMaximumcurrentallowedtodrawthrougheachgateoutput:8mATotallyleadfreeTTLoutputsMaximumRiseTime:15nsMaximumFallTime:15nsOperatingtemperature:0Cto70CApplication▪Indifferentlogiccircuit▪Indifferentservers▪Indifferentstoragemoduletostoredata▪Indifferentdigitalreluctancescircuitsandinstruments▪IndifferentnetworkingsystemsPinoutPinNumberDescriptionINPUTOFINVERTINGGATES11A-INPUTofGATE132A-INPUTofGATE253A-INPUTofGATE394A-INPUTofGATE4115A-INPUTofGATE5136A-INPUTofGATE6SHAREDTERMINALS7GND-Shouldbeconnectedtoground14VCC-ShouldbeconnectedtopositivevolatgeOUTPUTOFINVERTINGGATES21Y-OUTPUTofGATE142Y-OUTPUTofGATE263Y-OUTPUTofGATE384Y-OUTPUTofGATE4105Y-OUTPUTofGATE5126Y-OUTPUTofGATE6CircuitDiagramPackageParametersTechnologyFamilyLSVCC(Min)(V)4.75VCC(Max)(V)5.25Channels(#)6IOL(Max)(mA)8IOH(Max)(mA)-0.4ICC(Max)(uA)33InputtypeBipolarOutputtypePush-PullFeaturesHighspeed(tpd10-50ns),InputclampdiodeDatarate(Mbps)70ElectricalCharacteristicsProductComplianceECCNEAR99USHTS8542390001ComponentDatasheetDatasheet74LS04DatasheetProductManufacturerTexasInstrumentsInc.(TI)isanAmericantechnologycompanythatdesignsandmanufacturessemiconductorsandvariousintegratedcircuits,whichitsellstoelectronicsdesignersandmanufacturersglobally.ItsheadquartersareinDallas,Texas,UnitedStates.TIisoneofthetoptensemiconductorcompaniesworldwide,basedonsalesvolume.TexasInstrumentssfocusisondevelopinganalogchipsandembeddedprocessors,whichaccountsformorethan80%oftheirrevenue.TIalsoproducesTIdigitallightprocessing(DLP)technologyandeducationtechnologyproductsincludingcalculators,microcontrollersandmulti-coreprocessors.Todate,TIhasmorethan43,000patentsworldwide.FAQWhatis74LS04?74LS04isamemberof74XXYYICseries.The74-seriesaredigitallogicintegratedcircuits.74LS04IChassixNOTgates.TheseNOTgatesperformInvertingfunction.HencenameHEXINVERTINGGATES.Whatisthefunctionofic74ls04?74LS04HexNOTGateIC.74LS04isa2inputquadruple8-bitNOTgateIC.InverterinlogicconvertersisanelectronicsdevicewhosebasicfunctionsaretoinverttheincominglogicweatheritisHIGHorLOW.TheyarealsoknownasNOTgates.Whatisahexinverter?Ahexinverterisatypeofanintegratedcircuitthatcontainssixinverters.Manysophisticateddigitaldevicesuseinverters,includingmultiplexers,decoders,andstatemachines.Aninvertercircuitsmainfunctionistooutputthevoltagerepresentingtheoppositeleveltoitsinput.WhyisNOTgatecalledaninverter?ANOTgate,oftencalledaninverter,isanicedigitallogicgatetostartwithbecauseithasonlyasingleinputwithsimplebehavior.ANOTgateperformslogicalnegationonitsinput.Inotherwords,iftheinputistrue,thentheoutputwillbefalse.Whatarethe7basiclogicgates?Therearesevenbasiclogicgates:AND,OR,XOR,NOT,NAND,NOR,andXNOR.TheANDgateissonamedbecause,if0iscalledfalseand1iscalledtrue,thegateactsinthesamewayasthelogicalandoperator.ThefollowingillustrationandtableshowthecircuitsymbolandlogiccombinationsforanANDgate.

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IntroductionAcircuitordevicethatchangesthephaseofasignalby180,asrequiredforfeedingapush-pullamplifierstagewithoutusingacouplingtransformer,orforchangingthepolarityofapulse;atriodeiscommonlyusedasaphaseinverter.Alsoknownasinverter.Thefollowingisanintroductionto74LS04andothersimilarICchips.CatalogIntroductionI74LS04VS.74LS141.1BriefIntroduction1.2Differencebetween74LS04and74LS14II74LS04VS.74LS08III74LS04VS.74HC04IV74LS04VS.54LS04FAQOrdering&QuantityI74LS04VS.74LS141.1BriefIntroductionBoth74LS04and74LS14arenotgatesofthe74series.74LS04isaHexInverter.74LS14isaHexSchmidttrigger.The74LS04gatecircuithasathresholdvoltage.Whentheinputvoltagerisesfromthelowleveltothethresholdvoltage,ordecreasesfromthehighleveltothethresholdvoltage,theconditionofthecircuitwillchange.74LS14isaSchmidttrigger.Itisaspecialgatecircuit,whichisnotcompatiblewiththesimplegatecircuit.Schmidttriggerhastwothresholdvoltages(positivethresholdvoltageandnegativethresholdvoltage).1.2Differencebetween74LS04and74LS14◾Output:Theoutputof74LS04and74LS14arethesame.Ifthesamemanufacturer,theoutputparametersarethesame.◾Input:Thedifferencebetweenthetwoisthattheinputisnotthesame.74LS04inputisTTLlevel,while74LS14inputisSchmidtinput(withhysteresischaracteristics).Becausetheinputisdifferent,theapplicationofthetwochipsisalsodifferent.74LS04ismostlyusedfornoncontrolofgeneraldataontheboard,while74LS14isgenerallyusedforsignalshapingorsignalbufferingofcriticalsignals.Inmostcases,74LS14canreplace74LS04.II74LS04VS.74LS08The74LS08devicecontains4independent2-inputANDgates.Thelogicfunctionexpressionof74LS08is:Y=ABorY=/(A+B),positivelogic.74LS08iscommonlyusedindigitalcircuitsystems.74LS0474LS08VCC(Min)(V)4.754.75VCC(Max)(V)5.255.25LogiclevelTTLTTLPin/Package14PDIP,14SO,14SOIC,14SSOPPDIP14,SOIC14,SOP14,SSOP14III74LS04VS.74HC0474HC04isahexinverterofCMOScircuit,andtheworkingvoltageis2V-6V.Both74LS04and74HC04areinverters,butLSstandsforlow-powerSchottkyandHCishigh-speedCOMS.LSisslightlyfasterthanHC.LSadoptsTTLlevel.HCisCMOSlevel.74HC04iseasytounderstand.Inputlowlevel,outputhighlevel.Inputhighlevel,outputlowlevel.74LS04containssixindependentgateseachofwhichperformsthelogicINVERTfunction.Theoutputsignalsofthesixinvertersareoppositetotheinputsignals.Theinvertercanreversethephaseoftheinputsignalby180degrees.Thiscircuitisusedinanalogcircuits,suchasaudioamplifier,clockoscillator,etc.IV74LS04VS.54LS0454LS04containssixindependentinverters.Itischaracterizedforoperationoverthefullmilitarytemperaturerangeof-55℃to125℃.74LS0454LS04TechnologyFamilyLSLSVCC(Min)(V)4.754.5VCC(Max)(V)5.255.5Bits(#)66Voltage(Nom)(V)55F@NomVoltage(Max)(Mhz)3535ICC@NomVoltage(Max)(mA)0.0330.033tpd@NomVoltage(Max)(ns)2222IOL(Max)(mA)88IOH(Max)(mA)-0.4-0.4SchmittTriggerNoNoRatingCatalogMilitaryOperatingTemperatureRange(C)0to70-55to125Pin/Package14PDIP,14SO,14SOIC,14SSOP14CDIP,14CFP,20LCCCFAQWhatis74LS04?74LS04isamemberof74XXYYICseries.The74-seriesaredigitallogicintegratedcircuits.74LS04IChassixNOTgates.TheseNOTgatesperformInvertingfunction.HencenameHEXINVERTINGGATES.Whatisthefunctionofic74ls04?74LS04HexNOTGateIC.74LS04isa2inputquadruple8-bitNOTgateIC.InverterinlogicconvertersisanelectronicsdevicewhosebasicfunctionsaretoinverttheincominglogicweatheritisHIGHorLOW.TheyarealsoknownasNOTgates.Whatisahexinverter?Ahexinverterisatypeofanintegratedcircuitthatcontainssixinverters.Manysophisticateddigitaldevicesuseinverters,includingmultiplexers,decoders,andstatemachines.Aninvertercircuitsmainfunctionistooutputthevoltagerepresentingtheoppositeleveltoitsinput.WhyisNOTgatecalledaninverter?ANOTgate,oftencalledaninverter,isanicedigitallogicgatetostartwithbecauseithasonlyasingleinputwithsimplebehavior.ANOTgateperformslogicalnegationonitsinput.Inotherwords,iftheinputistrue,thentheoutputwillbefalse.DescriptionTIP122isanNPNDarlingtontransistor.Darlingtontransistormeanstherearetwotransistorinonepackageconnectedtoincreasegainatoutput.TIP122transistorhasalotofgoodfeatureslike5Acollectorcurrent,maxemitter-basevoltageis5V,maxcollectordissipationis65watt,minimummaximumcurrentgainisequalto1000.Thistransistorisdesignedtouseasaswitchandforamplificationpurposes.CatalogDescriptionTIP122ComponentDatasheetTIP122PinoutTIP122FeaturesTIP122ApplicationsTIP122EnvironmentalandExportClassificationsTIP122ParametersWorkingofTIP122HowtoSafelyLongRuninaCircuitDarlingtonCircuitSchematicWheretouseTIP122HowtouseTIP122TIP122ReplacementandEquivalentComplementofTIP122TIP122AlternativeNPNTransistorsTIP122SameFamilyTransistorsAdditionalResourcesFAQOrdering&QuantityTIP122ComponentDatasheetResourceTypeLinkDatasheetsTIP120-22TIP120-22,TIP125-27TO220B03PkgDrawingPCNObsolescence/EOLMultipleDevices19/Jun/2009MultDeviceEOL19/May/2017PCNDesign/SpecificationHeatsinkDesingChanges24/Feb/2014Logo17/Aug/2017PCNPackagingTapeandBox/ReelBarcodeUpdate07/Aug/2014MultDevices24/Oct/2017HTMLDatasheetTO220B03PkgDrawingTIP122PinoutPinNumberPinNameDescription1BaseItgovernsthebiasingofthetransistorandworkstoturnONorOFFthetransistor.2CollectorCurrentflowsinthroughcollector,usuallyconnectedtoload3EmitterCurrentcomesoutbytheemitter,itisusuallylinkedtoground.TIP122FeaturesHighDCCurrentGainhFE=2500(Typ)@IC=4.0AdcCollectorEmitterSustainingVoltage@100mAdcVCEO(sus)=60Vdc(Min)TIP120,TIP125=80Vdc(Min)TIP121,TIP126=100Vdc(Min)TIP122,TIP127LowCollectorEmitterSaturationVoltageVCE(sat)=2.0Vdc(Max)@IC=3.0Adc=4.0Vdc(Max)@IC=5.0AdcMonolithicConstructionwithBuiltInBaseEmitterShuntResistorsPbFreePackagesareAvailable*TIP122ApplicationsAudioAmplifierAudioAmplifierStagesAudioPreamplifiersSwitchingLoadsUnder5ATIP122EnvironmentalandExportClassificationsAttributeDescriptionRoHSStatusRoHSnon-compliantMoistureSensitivityLevel(MSL)1(Unlimited)TIP122ParametersBaseProductNumberTIP122CategoryDiscreteSemiconductorProducts-Transistors-Bipolar(BJT)-SingleCollector-BaseVoltageVCBO100VConfigurationSingleCurrent-Collector(Ic)(Max)5ACurrent-CollectorCutoff(Max)500ADCCurrentGain(hFE)(Min)@Ic,Vce1000@3A,3VDescriptionTRANSNPNDARL100V5ATO220ABDetailedDescriptionBipolar(BJT)TransistorEmitter-BaseVoltageVEBO5VFactoryPackQuantity200Height9.4mmLength10.67mmManufacturerONSemiconductorManufacturerProductNumberTIP122MaximumCollectorCut-offCurrent200uAMaximumDCCollectorCurrent5AMaximumOperatingTemperature+150CMinimumOperatingTemperature-65CMountingStyleThroughHoleMountingTypeThroughHoleOperatingTemperature-65C~150C(TJ)PackagingBulkPartStatusObsoletePower-Max2WProductTypeDarlingtonTransistorsSeriesTIP122SubcategoryTransistorsTransistorTypeNPN-DarlingtonUnitWeight0.042329ozVceSaturation(Max)@Ib,Ic4V@20mA,5AVoltage-CollectorEmitterBreakdown(Max)100VWidth4.83mmWorkingofTIP122Thistransistorisrecognizedforitshighercurrentgainwhichis1000andhighercollectorcurrent5amperes,therefore,itisusuallyusedtoswitchThistransistorhaslessbaseandemitterVoltageofthemerely5VhenceforthcanbeeffortlesslyorganizedbyaLogicinstrumentsuchasamicrocontrollerThoughprecautionhastobeengagedtocheck,ifthelogicinstrumentscanfontupto120mA.ThoughTIP122hasextraordinarycurrentatcollectorandcurrentgain,itisimpartiallymodesttoswitchtheexpedientmeanwhileithasanEmitter-Basevoltage(VBE)oftheonly5VandIbofmerely120mA.HowtoSafelyLongRuninaCircuitTogetbetterperformancewiththisdarlingtiontransistorwesuggesttoalwaysstayingbelowitsmaximumratings.Donotoperateitincircuitsusingmorethan100V.Donotprovideloadmorethan5A.Alwaysuseasuitablebaseresistortoproviderequiredcurrentatitsbase.Useasuitableheatsinktosaveitfromoverheatinganddostoreoruseitintemperaturebelow-65centigradeandabove+150centigrade.DarlingtonCircuitSchematicWheretouseTIP122Thistransistorisknownforitshighcurrentgain(hfe=1000)andhighcollectorcurrent(IC=5A)henceitisnormallyusedtocontrolloadswithhighcurrentorinapplicationswherehighamplificationisrequired.ThistransistorhasalowBase-EmitterVoltageoftheonly5VhencecanbeeasilycontrolledbyaLogicdevicelikemicrocontrollers.Althoughcarehastobetakentocheckifthelogicdevicecansourceupto120mA.So,ifyoulookingforatransistorthatcouldbeeasilycontrolledbyaLogicdevicetoswitchhighpowerloadsortoamplifyhighcurrentthenthisTransistormightbeanidealchoiceforyourapplication.HowtouseTIP122AlthoughTIPhashighcollectorcurrentandcurrentgain,itisfairlysimpletocontrolthedevicesinceithasanEmitter-Basevoltage(VBE)ofonly5Vandbasecurrentofonly120mA.InthebelowcircuitIhaveusedtheTIP122tocontrola48Vmotorwhichhasacontinuouscurrentofabout3A.Thecontinuescollectorcurrentofthistransistoris5Aandourloadconsumesonly3Awhichisfine.Themaximumbasecurrentisabout120mA,butIhaveusedhighvalueof100ohmresistortolimititto42mA.Youcanuseevena1Kresistorifyourcollectorcurrentrequirementisless.Thepeak(pulse)currentofthistransistoris8Asomakesureyourmotordoesnotconsumemorethanthat.Thisisjustamodelcircuitdiagramthatshowstheworkingonthistransistoritcannotbeusedassuch.So,similarlyyoucancontrolyourloadinthesameway.TIP122ReplacementandEquivalentTIP132,TIP102,NTE261,NTE263,2N6045,2N6045G,2SD2495,BDT65B,2N6532,BDT63B,BDW43,TIP142T(PinconfigurationofsometransistorsmaydifferfromTIP122,checkpinconfigurationbeforereplacinginacircuit)TIP22isadarlingtionpairtransistormanufacturedinTO-220package,itsagoodtransistortouseasahighgainswitchoramplifier.ComplementofTIP122ThecomplementoftheTIP122transistorisTIP127.TIP122AlternativeNPNTransistorsBC547,BC548,BC549,BC636,BC639,2N2369,2N3055,2N3904,2N3906,2SC5200TIP122SameFamilyTransistorsNPNFamilytransistorsareTIP120,TIP121,TIP122,andPNPFamilyareTIP125,TIP126,TIP127(PNP)AdditionalResourcesAttributeDescriptionOtherNamesTIP122FSTIP122FS-NDTIP122FS-NDRTIP122OSFAQWhatisTIP122transistor?TIP122TransistorisanNPNDarlingtontransistor....TIP122Darlingtontransistorhasalotofgoodfeatures,like5Acollectorcurrent,maximumemitter-basevoltageis5V,maximumcollectordissipationis65watt,andsoon.Thistransistorismanufacturedtouseasaswitchandforamplificationpurposes.WhattypeofpackageisusedforTIP122transistor?TheTIP122isasiliconNPNDarlingtontransistorinaTO-220typepackagedesignedforgeneralpurposeamplifierandlow-speedswitchingapplications.HowdoyoutestatransistorTIP122?Harvino.Theproperwaytotestistosetyourdmmtodiodetest(usually2ksettingontheohmscale).Transistorshavethreelegs;anemitter,abase,andacollector.HowdoIknowifmytransistorisblown?Connectthebaseterminalofthetransistortotheterminalmarkedpositive(usuallycolouredred)onthemultimeter.Connecttheterminalmarkednegativeorcommon(usuallycolouredblack)tothecollectorandmeasuretheresistance.Itshouldreadopencircuit(thereshouldbeadeflectionforaPNPtransistor).Whatarethe3terminalsofatransistor?Abipolartransistorhasterminalslabeledbase,collector,andemitter.Asmallcurrentatthebaseterminal(thatis,flowingbetweenthebaseandtheemitter)cancontrolorswitchamuchlargercurrentbetweenthecollectorandemitterterminals.HowtomakeminiaudioamplifieruseTIP122/TIP127transistor?IntroductionLM339(Quaddifferentialcomparator)consistoffourindependentvoltagecomparators.Itisacommonintegratedcircuitandismainlyusedinhigh-voltagedigitallogicgatecircuits.UsingLM339caneasilyformvariousvoltagecomparatorcircuitsandoscillatorcircuits.CatalogIntroductionCatalogICircuitofSingleLimitComparatorIIOverheatDetectionandProtectionCircuitIIIHysteresisComparatorIVOver-voltageDetectionCircuitVDoubleLimitComparatorVIUsingLM339toformanOscillatorFAQOrdering&QuantityICircuitofSingleLimitComparatorFigure(a)showsabasicsinglelimitcomparator.AddtheinputsignalUIN(i.e.voltagetobecompared)tothein-phaseinputterminal,andconnectareferencevoltageUrattheanti-phaseinputterminal.WhentheinputvoltageUinUr,theoutputishighlevelUOH.Figure(b)showsitstransmissioncharacteristics.Figure1.CircuitofSingleLimitComparatorIIOverheatDetectionandProtectionCircuitItispoweredbyasinglepowersupply.Afixedreferencevoltageisaddedtotheanti-phaseinputterminalof1/4LM339,anditsvaluedependsonR1andR2.UR=R2/(R1+R2)*UCC.Thevoltageatthein-phaseterminalisequaltothevoltagedropofthethermistorRT.Whenthetemperatureinsidethemachineisbelowthesetvalue,the+terminalvoltageisgreaterthanthe-terminalvoltage,andUoisahighpotential.Whenthetemperaturerisesabovethesetvalue,the-terminalvoltageisgreaterthanthe+terminal,andtheUooutputisatzeropotential,whichcausestheprotectioncircuittooperate.AdjustingthevalueofR1canchangethethresholdvoltage,whichsetsthetemperaturevalue.Figure2.OverheatDetectionandProtectionCircuitIIIHysteresisComparatorThehysteresiscomparatorcanalsoberegardedasasinglelimitcomparatorwithpositivefeedback.Inthesinglelimitcomparatordescribedabove,iftheinputsignalUinhasslightinterferencenearthethreshold,theoutputvoltagewillproducecorrespondingundulation.Thisshortcomingcanbeovercomebyintroducingpositivefeedbackintothecircuit..Figure(a)showsahysteresiscomparator.ThefamiliarSchmidtcircuitisacomparatorwithhysteresis.Figure(b)showsthetransmissioncharacteristicsofthehysteresiscomparator.Figure3.HysteresisComparatorItisnotdifficulttoseethatoncetheoutputstateischanged,theoutputvoltagewillbestableaslongastheinterferencenearthejumpvoltagevaluedoesnotexceedthevalueofU.Accordingly,itcomestoareductioninresolution.Forthehysteresiscomparator,itcantdistinguishtwoinputvoltageswhosedifferenceislessthanU.Thehysteresiscomparatorwithpositivefeedbackcanacceleratetheresponsespeedofthecomparator,whichisoneofitsadvantages.Inaddition,sincethepositivefeedbackaddedbythehysteresiscomparatorisverystrongandmuchstrongerthantheparasiticcouplinginthecircuit,thehystericcomparatorcanalsoavoidtheself-oscillationcausedbytheparasiticcouplingofthecircuit.IVOver-voltageDetectionCircuitFigure4showsthepartofover-voltagedetectioncircuitinaninductioncookercircuit.Whenthegridvoltageisnormal,1/4lm339u42.8v,thecomparatorturnsover.Theoutputis0VandBG1iscutoff.ThevoltageofU5iscompletelydeterminedbythepartialvoltagevalueofR1andR2,whichis2.7V.ItmakesU4largerthanU5,whichmakesthestateafteroverturningextremelystableandavoidstheinstabilitycausedbythesmallfluctuationofgridvoltageneartheover-voltagepoint.Duetocertainhysteresis,afterovervoltageprotection,theinductioncookerstartstoworkagainwhenthegridvoltagedropsto242-5=237vandU4U3.Figure4.Over-voltageDetectionCircuitVDoubleLimitComparatorThecircuitinFigure5consistsoftwoLM339toformawindowcomparator.WhenthecomparedsignalvoltageUinisbetweenthethresholdvoltages(UR1UinUR2),theoutputishighpotential(UO=UOH).WhenUinisnotbetweenthethresholdpotentialrange,(UinUR2orUinUR1)theoutputislowpotential(UO=UOL),andthewindowvoltageU=UR2-UR1.Itcanbeusedtojudgewhethertheinputsignalpotentialisbetweenthespecifiedthresholdpotential.Figure5.DoubleLimitComparatorVIUsingLM339toformanOscillatorFigure6showsthecircuitofanaudiosquarewaveoscillatorcomposedof1/4LM339.ChangingC1canchangethefrequencyoftheoutputsquarewave.Inthiscircuit,whenC1=0.1uF,f=53Hz;whenC1=0.01uF,f=530Hz;whenC1=0.001uF,f=5300Hz.LM339canalsoformahigh-voltagedigitallogicgatecircuit,andcandirectlyinterfacewithTTLandCMOScircuits.Figure6.LM339OscillatorFAQWhatisLM339?LM339isavoltagecomparatorICfromLMx39xseriesandismanufacturedbymanyindustries.Thedevicesconsistoffourindependentvoltagecomparatorsthataredesignedtooperatefromasinglepowersupply.WhatisthedifferencebetweenLM324andLM339?TheLM324hasacomplementaryoutputwhiletheLM339isopencollector.Inthecomplementaryoutput,currentcanflowineitherdirectionasrequired(eithersourceorsink)whiletheopencollectoroutputcanonlysinkcurrent.HowdoesLM339comparatorwork?TheLM339isaquadopampcomparator.Acomparatorworksbyasimpleconcept.Eachopampofacomparatorhas2inputs,ainvertinginputandanoninvertinginput.Iftheinvertinginputvoltageisgreaterthanthenoninvertinginput,thentheoutputisdrawntoground.Whatiscomparatoric?Acomparatorisanelectroniccircuit,whichcomparesthetwoinputsthatareappliedtoitandproducesanoutput.Theoutputvalueofthecomparatorindicateswhichoftheinputsisgreaterorlesser.Pleasenotethatcomparatorfallsundernon-linearapplicationsofICs.WhatisthereplacementforLM339?LM311,LM324,LM397,LM139,LM239,LM2901Whatisacomparatorcircuit?Acomparatorcircuitcomparestwovoltagesandoutputseithera1(thevoltageattheplusside;VDDintheillustration)ora0(thevoltageatthenegativeside)toindicatewhichislarger.Comparatorsareoftenused,forexample,tocheckwhetheraninputhasreachedsomepredeterminedvalue.WhatistheuseofLM339?LM339isusedinapplicationswhereacomparisonbetweentwovoltagesignalsisrequired.Inadditionwithfourofthosecomparatorsonboardthedevicecancomparefourpairsofvoltagesignalsatatimewhichcomesinhandyinsomeapplications.

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IIntroductionInthisblog,wecomparetheLM339andLM339NproducedbyTI.Thecontentofcomparisonincludescomponentparameters,packaging,applicationareas,andtheircircuitdiagrams,etc.HopethisblogishelpfultothoseinterestedinLM339orLM339N.LM339NCatalogIIntroductionIIComponentDatasheetIIIDifferenceBetweenLM339andLM339NIVParametersVFeaturesVIApplicationsVIIPinoutFAQOrdering&QuantityIIComponentDatasheetComponentDatasheet1LM339NDatasheetComponentDatasheet2LM339DatasheetIIIDifferenceBetweenLM339andLM339N◾LM339Nisaquadvoltagecomparator.Itadoptsdualin-line14-pinpackage.Themaximumoperatingvoltageis18Vandthepowerconsumptionis265mW.Itisusedininductioncookersandotherproducts.◾LM339(Quaddifferentialcomparator)consistoffourindependentvoltagecomparators.Itisacommonintegratedcircuitandismainlyusedinhigh-voltagedigitallogicgatecircuits.LM339commonmoderangeisverylarge,from0vtothepowersupplyvoltage-1.5v;widesupplyvoltagerange:singlepowersupplyis2-36V;dualpowersupplyvoltageis1V~18V.IVParametersParametersLM339NLM339Numberofchannels(#)44OutputtypeOpen-collector,Open-drainOpen-collectorPropagationdelaytime(s)0.70.3Vs(Max)(V)3630Vs(Min)(V)22Vos(offsetvoltage@25C)(Max)(mV)55Iqperchannel(Typ)(mA)0.20.2Inputbiascurrent(+/-)(Max)(nA)25050Rail-to-railOutOutRatingCatalogCatalogOperatingtemperaturerange(C)0to700to70FeaturesStandardcomparatorStandardcomparatorVICR(Max)(V)3428.5VICR(Min)(V)00Approx.price(US$)1ku|0.241ku|0.05VFeaturesLM339NLM339WideSupplyVoltageRangeLM139/139ASeries2to36VDCor1to18VDCLM2901-N:2to36VDCor1to18VDCLM3302-N:2to28VDCor1to14VDCVeryLowSupplyCurrentDrain(0.8mA)IndependentofSupplyVoltageLowInputBiasingCurrent:25nALowInputOffsetCurrent:5nAOffsetVoltage:3mVInputCommon-ModeVoltageRangeIncludesGNDDifferentialInputVoltageRangeEqualtothePowerSupplyVoltageLowOutputSaturationVoltage:250mVat4mAOutputVoltageCompatibleWithTTL,DTL,ECL,MOS,andCMOSLogicSystemsWideSupplyRangesSingleSupply:2Vto36V(Testedto30VforNon-VDevicesand32VforV-SuffixDevices)DualSupplies:1Vto18V(Testedto15VforNon-VDevicesand16VforV-SuffixDevices)LowSupply-CurrentDrainIndependentofSupplyVoltage:0.8mA(Typical)LowInputBiasCurrent:25nA(Typical)LowInputOffsetCurrent:3nA(Typical)(LM139)LowInputOffsetVoltage:2mV(Typical)Common-ModeInputVoltageRangeIncludesGroundDifferentialInputVoltageRangeEqualtoMaximum-RatedSupplyVoltage:36VLowOutputSaturationVoltageOutputCompatibleWithTTL,MOS,andCMOSOnProductsComplianttoMIL-PRF-38535,AllParametersAreTestedUnlessOtherwiseNoted.OnAllOtherProducts,ProductionProcessingDoesNotNecessarilyIncludeTestingofAllParameters.VIApplicationsLM339NLM339High-PrecisionComparatorsReducedVOSDriftOvertemperatureEliminatesNeedforDualSuppliesAllowsSensingNearGNDCompatibleWithAllFormsofLogicPowerDrainSuitableforBatteryOperationIndustrialAutomotiveInfotainmentandClustersBodyControlModulesPowerSupervisionOscillatorsPeakDetectorsLogicVoltageTranslationVIIPinoutLM339andLM339NsharethesamepinoutdiagramFAQWhatisLM339?LM339isavoltagecomparatorICfromLMx39xseriesandismanufacturedbymanyindustries.Thedevicesconsistoffourindependentvoltagecomparatorsthataredesignedtooperatefromasinglepowersupply.WhatisthedifferencebetweenLM324andLM339?TheLM324hasacomplementaryoutputwhiletheLM339isopencollector.Inthecomplementaryoutput,currentcanflowineitherdirectionasrequired(eithersourceorsink)whiletheopencollectoroutputcanonlysinkcurrent.HowdoesLM339comparatorwork?TheLM339isaquadopampcomparator.Acomparatorworksbyasimpleconcept.Eachopampofacomparatorhas2inputs,ainvertinginputandanoninvertinginput.Iftheinvertinginputvoltageisgreaterthanthenoninvertinginput,thentheoutputisdrawntoground.Whatiscomparatoric?Acomparatorisanelectroniccircuit,whichcomparesthetwoinputsthatareappliedtoitandproducesanoutput.Theoutputvalueofthecomparatorindicateswhichoftheinputsisgreaterorlesser.Pleasenotethatcomparatorfallsundernon-linearapplicationsofICs.WhatisthereplacementforLM339?LM311,LM324,LM397,LM139,LM239,LM2901Whatisacomparatorcircuit?Acomparatorcircuitcomparestwovoltagesandoutputseithera1(thevoltageattheplusside;VDDintheillustration)ora0(thevoltageatthenegativeside)toindicatewhichislarger.Comparatorsareoftenused,forexample,tocheckwhetheraninputhasreachedsomepredeterminedvalue.WhatistheuseofLM339?LM339isusedinapplicationswhereacomparisonbetweentwovoltagesignalsisrequired.Inadditionwithfourofthosecomparatorsonboardthedevicecancomparefourpairsofvoltagesignalsatatimewhichcomesinhandyinsomeapplications.IDescriptionThisblogmainlydiscussesandsolvesthefollowingproblem:HowtouseLM339voltagecomparatortomakeareservoirwaterlevelgauge?Accordingtowaterlevel,thisdesignperformssignalprocessingandcontrolsthepotentialofmultiplevoltagecomparators,sotheoutputwillchangeaccordingly.Therefore,underitsdrive,LEDcannotonlyemitlight,butalsoachievetheeffectofindicatingthewaterlevel.Figure1.LM339CatalogIDescriptionIIIntroductionIIIWokingPrincipleIVDeviceselectionandComponentProduction4.1deviceselection4.2PartProductionVInstallationandDebugging5.1DetectionPart5.2DisplayPartVIConclusionFAQOrdering&QuantityIIIntroductionDuetoinsufficientwatersupplyinsomeresidentialareas,pumpworkersmustfirststorewaterinthereservoirandthensupplywaterinaregularmanner.Inthisway,thepumpworkermustknowthewaterlevelofthereservoiratanytimeinthepumproom.Inthepast,electrodessuchascopperrodsorstainlesssteelwereusedtodetectthewaterlevelofthepool.However,duetoelectriccorrosion,thefunctionoftheelectrodeislostsoonafteruse.Forthisreason,thisblogusesLM339voltagecomparatortomakewaterlevelgauge.Thisnotonlyeliminatesthepainofoftenchangingelectrodes,butalsosimpleandeasy.Howsimpleisit?Onlytwowiresneedtobeconnectedfromthereservoirtothepumproom.Aftermorethantwoyearsofoperation,itsperformancehasbeenstableandreliable,achievingtheexpectedresults.IIIWokingPrincipleThemaincircuitofthewaterlevelgaugeiscomposedof4LM339voltagecomparators.Thiskindofintegratedcircuithasthecharacteristicsofeasypurchase,lowprice,singlepowersupplyoperationandwidedifferentialrange.EachLM339has4independentvoltagecomparators(15inthisdesign).Aslongasthepotentialdifferencebetweenthepositiveandnegativeinputterminalsis10mV,theoutputterminalcanbereliablyswitchedfromonestatetoanother.Whenthepositiveinputterminalis10mVhigherthanthenegativeinputterminal,itsoutputterminalishigh;Whenthenegativeinputis10mVhigherthanthepositiveinput,itsoutputislow.Inaddition,LEDscanbedrivendirectly.ThenhowtomaketheoutputendofLM339havehighandlowlevelchanges?Inspecificuse,anappropriateresistanceisgenerallyaddedbetweentheoutputterminalandthepositivepowersupply.Thisresistoriscalledapull-upresistor.Thatis,whentheoutputterminalofLM339isinahighimpedancestate,thepotentialoftheoutputterminalispulledupbytheresistor.Figure2.BlockDiagramofWaterLevelGaugeTheprincipleblockdiagramofthedeviceisshowninFigure2.Thevoltagesignalmeasurementconsistsofareedswitchandavoltagedividerresistor.Theringmagnetssuspendedinthewaterareindifferentpositions.Duetotheprincipleofelectromagneticinduction,notonlythecorrespondingdryreedswitchnormallyopencontactsareclosed,butalsothecorrespondingvoltagedividerresistorisconnected.Therefore,thecircuitwillpickupdifferentvoltagesignals.Thepotentialofthenegativeinputterminalofthecomparatorisformedbyafixedvoltagedividerresistor.Themeasuredvoltagesignaliscomparedwiththesetpotential.TheresultofthisisthattheLEDdisplaysthewaterlevelwhendriven.Inaddition,analarmisissuedwhenthehighestwaterlevelisreachedtoremindthepumpertostopwaterinjectiontopreventwateroverflow.TheconcretecircuitisshownasinFig.3.Figure3.WaterLevelGaugeCircuitDiagramInFigure3,thepowersupplyis+12V,andthedepthofthepoolisdividedinto15segmentsfordisplay.Inthispicture:A1~A15arevoltagecomparatorscomposedofLM339;GK1~GK15aredryreedswitches,thenormallyopencontactisclosedwhentheringmagnetisclosetoacertaindryreedswitch;ThevoltagedividercircuitcomposedofresistorsR1toR15determinesthepotentialofthepositiveinputterminalofeachcomparator.ThevoltageofthepositiveinputterminalofLM339changesduetothedifferentpositionsofthemagneticsteel.ThevoltagedividercircuitcomposedofresistorsR01~R030determinesthepotentialofthenegativeinputterminalofeachcomparator.Thepotentialofeachnegativeinputterminalisfixedafterdetermination.Whenthemagneticsteelfloatingonthewatersurfaceisclosetoacertaindryreedswitch,duetothepartialpressureofR1,R2,,R15,thepositiveinputterminalsofthecomparatorsA1,A2,,A15havedifferentinputs.Afterthissignaliscomparedwiththepotentialsetatthenegativeinputofthecomparator,therewillbeacorrespondingoutput.FromFigure3,whenGK1pullsin,itisequivalenttoholdingthemagneticsteelfloatattheupperlimitwaterlevel.Thepositiveinputofeachcomparatorisequaltothegroundpotential,whichislowerthantheirnegativeinput.Therefore,theoutputterminalsarealllowlevel,sothatallLEDsarelit.Atthistime,theoutputofA1dropsfromhighleveltolowlevel,andNE555istriggeredthroughcapacitorC.NE555isconnectedasamonostablecircuit.Oncetriggered,its3pinwilloutputahighlevel,whichwilldrivethebuzzertoalarm.ItsdurationisdeterminedbytheRCcomponentsconnectedtothe6and7pins.WhenGK2isclosed,LED2~LED15shouldbeonandLED1shouldbeoff.Atthistime,thepotentialofthepositiveinputterminalofeachcomparatorishigherthanthepotentialofthenegativeinputterminalofA1andlowerthanthepotentialofthenegativeinputterminalofA2~A15,andsoon.IVDeviceselectionandComponentProduction4.1deviceselectiona.SetthenegativeinputpotentialofeachcomparatortoVsh.Thenegativeinputpotentialofeachcomparatorissetartificiallyaccordingtothenumberofsegmentsdividedintopowersupplyandwaterdepth.Becausethepooldepthhasbeendividedinto15segmentsfordisplay,startingfrom2.0V,thedifferencebetweeneachadjacentnegativeinputterminalis0.4V.AsshowninthefirstrowinTable1.b.Selecttheresistancebetweenthenegativeinputterminalofeachcomparatorandthepowersupply,thatis,thevoltagedividerresistanceR01=R03==R029=20k,settoR.c.CalculatethegroundresistanceR02,R04,...,R030,whichisRr.SupposetheresistanceofthenegativeinputterminaltogroundisRr,andthepotentialofeachnegativeinputterminalisVsh,accordingtocircuitdiagram3:(1)Fromthisformula:(2)Forexample,tomakethepotentialofthenegativeinputterminalofthevoltagecomparatorA1Vsh=2V,accordingtoequation(2),wecangetAsshowninthesecondrowandthefirstcolumninTable1.TheselectionoftheotherresistorsR04,R06,,R030canbecalculatedaccordingtotheaboveformula(theresultisatheoreticalvalue,seethedatashowninthesecondrowinTable1fordetails).d.DeterminethenominalresistanceRbfromRr.Infact,thenominalvalueofcommerciallyavailableresistorsisdifferentfromthiscalculatedvalue.Inspecificapplications,anominalresistanceRbwithasimilarresistancevaluecanbeselected.ThespecificvalueisshowninthethirdrowofTable1.e.DeterminethepotentialVofthenegativeinputterminalofeachcomparatorAbyRb.WhenthenominalvalueofresistanceRbisselected,usethefollowingformulatocheckthepotentialVgeneratedbythisresistance.(3)Thespecificpotentialvalueisshowninthe4throwofTable1,comparedwiththesetvalueinthe1strow,aslongasitdoesnotexceed0.1V.f.DeterminetheresistancesR1,R2,,R15ofthepositiveinputterminalsofeachcomparatorandsetthemasRzh.FirstfindR1,setthepositiveinputpotentialofeachcomparatorasVzh,whenGK1pullsin,itcanbeseenfromTable1that2VVzh2.4V,setVzh=2.2V,R=20k,accordingtoformula(3),itcanbelistedThesolutionisthatRzh=R14.5k.Thisresistanceisnotthenominalvalue.Chooseasimilarnominalvalueof4.8k.ThenfindtheotherresistancesR2,R3,,R15,whichcanallbecalculatedbythismethod.Theresultisthetheoreticalvalue,whichhasaslightdeviationinpractice.Aftercorrection,thevalueisshowninthefifthrowofTable1.Aftertheaboveparametersareselectedinthisway,itcanbeensuredthatwhenthewaterlevelinthepoolreachesthelowestlimitandthefloatholdingthemagneticsteelsinkstothelowestposition,themagneticsteelseparatesfromallthereedswitchesandtheLEDsareallextinguished;AndwhenthefirstreedswitchGK1isclosed(equivalenttothewaterlevelinthepoolreachesthehighestlimit,thefloatholdingthemagneticsteelrisestothehighestposition)LEDsareallon.Whenthefloatisatacertainpositioninthemiddle,thecorrespondingLEDandtheLEDsbelowareallon,andtheLEDaboveitisoff,toshowthewaterlevel.Aftertheabovecalculation,thespecificdatashowninTable1isobtained.4.2PartProductionItisnecessarytomeasuretheheightfromthelowestwaterlevelofthereservoirtothelimitwaterlevel,anddividethisheightinto15segments.Thedistanceofeachsegmentislessthan200mm,thisdistancecanensurethatthemagneticsteelcanalwaysattractanadjacentdryreedswitch,soastoavoiddisplaybreakpoints.Thatistopreventthemagneticsteelfromnotattractingtheupperdryreedpipeorthelowerdryreedpipeduringoperation,sothattheLEDdisplayisallextinguished,causingtheillusionofwaterlessness.FortheconnectionsofGK1,R1~GK15,R15,firstsolderthemtoasmallprintedcircuitboardwithawidthlessthanorequalto20mm,andthenusewirestoconnectthematadistanceoflessthanorequalto200mm,andencapsulatethemina25mmhardplastictube..Theupperandlowermouthsofthepipeshouldbetightlysealedtopreventwaterleakage.Thetubeiscoveredwitharing-shapedmagnet.Afterdroppinganon-ferromagneticheavyobjectonthelowerendofthehardplasticpipe,theplasticpipeisverticallysunkintothebottomofthereservoir.Aringfloatisplacedunderthemagneticsteelandissleevedonthetube,andtheupperendofthetubeisfixedontheobservationportabovethereservoir.Duetothefunctionofthefloat,themagneticsteelisalwayssuspendedonthewatersurface,risingandfallingwiththewatersurface.Notethattheplaneofthemagneticsteelshouldalwaysbeparalleltothewatersurface,andtheplasticpipeshouldbeverticaltothewatersurfacetopreventthemagneticsteelfrombeingstuckbyfrictionwiththepipewallwhenthewaterlevelrisesandfalls.VInstallationandDebuggingThewholedeviceconsistsoftwoparts:Itisadetectionpartcomposedofareedswitchandvariousvoltagedividers;ItisthesignalprocessingdisplaypartcomposedofLM339.5.1DetectionPartBeforeencapsulatingtheplastictube,putsomesilicagelinthetubetoabsorbthemoistureinthetubeandpreventthelineinthetubefromgettingdamp.Ifring-shapedmagneticsteelisusedasthedetectionelement,thereedpipeconnectedinseriesintheplastictubeshouldberealizedbytwostaggeredreedpipes.Accordingtotheelectromagneticinductiontheory,theanalysisofthemagneticfieldlinesofthemagneticsteelshowsthatthereareasmallsectionofmagneticfieldlinesparalleltotheplaneofthemagneticsteelattheupperandloweropeningsofthemagneticsteel.Whenthissectionisclosetothereedswitch,thedirectionofitsmagneticfieldlineisperpendiculartothedirectionofthereedofthereedswitch.Atthistime,althoughthereedswitchisveryclosetothemagneticsteel,thecontactisstillreleasedanddisconnected,whichwillmakealltheLEDsgoout.Iftwostaggeredreedpipesareusedinstead,theproblemcanbesolved,andthestaggereddistancecanbedeterminedinexperiments.5.2DisplayPartThewaterlevelofeachsegmentisdisplayedbygreen10LED,andthelimitwaterlevelisdisplayedbyeye-catchingredLED.IftheLEDsarearrangedneatlytogether,thewaterlevelinthepoolcanbeclearlyseenaccordingtotheonoroffoftheLEDs.Equippedwithabuzzer,itwillgivethepumpworkeraclearerreminder.Note:Fromthedetectorinthepooltothecircuitboardofthepumproom,itisbesttouseshieldedwiretopreventinterferencesignalsfromentering.Weshouldalsonotethatthepowersupplymustberegulated.Fugure4.lm339VIConclusionThenegativeinputpotentialofthevoltagecomparatorA1~A15composedofLM339shouldbesetaccordingtoacertainrule,andthepotentialintervalbetweeneachotherdependsonthedepthofthecell.Ifthewaterlevelisdeeper,theintervalcanbesmaller,andthenumberofsectionscanbeselectedmore.Thepotentialdifferencebetweenadjacentcomparatorsisgenerally0.4V.Ifthepotentialdifferenceislarge,theselectionoftheresistanceiseasy;ifthepotentialdifferenceissmall,becausethenominalvalueintervalofthegeneralresistanceislarge,itisnecessarytouseanadjustableresistortoadjustthepotential.Ofcourse,inthecaseofsmallintervals,thesmallestpotentialdifferencebetweeneachothershouldbegreaterthan10mV,otherwisetheinputcharacteristicsofLM339willnotbeabletodistinguishthepotentialbetweeneachother.Inaddition,thevoltageofthepowersupplyandthenominalvalueofeachresistancemustbeconsidered.Thismethodcanalsobeappliedtootherfields.Suchasmonitoringthewaterdepthofrivers,rivers,lakes,andbays,theoillevelofgasstations,andthedepthofwatertanksinwaterplants.FAQWhatisLM339?LM339isavoltagecomparatorICfromLMx39xseriesandismanufacturedbymanyindustries.Thedevicesconsistoffourindependentvoltagecomparatorsthataredesignedtooperatefromasinglepowersupply.WhatisthedifferencebetweenLM324andLM339?TheLM324hasacomplementaryoutputwhiletheLM339isopencollector.Inthecomplementaryoutput,currentcanflowineitherdirectionasrequired(eithersourceorsink)whiletheopencollectoroutputcanonlysinkcurrent.HowdoesLM339comparatorwork?TheLM339isaquadopampcomparator.Acomparatorworksbyasimpleconcept.Eachopampofacomparatorhas2inputs,ainvertinginputandanoninvertinginput.Iftheinvertinginputvoltageisgreaterthanthenoninvertinginput,thentheoutputisdrawntoground.Whatiscomparatoric?Acomparatorisanelectroniccircuit,whichcomparesthetwoinputsthatareappliedtoitandproducesanoutput.Theoutputvalueofthecomparatorindicateswhichoftheinputsisgreaterorlesser.Pleasenotethatcomparatorfallsundernon-linearapplicationsofICs.WhatisthereplacementforLM339?LM311,LM324,LM397,LM139,LM239,LM2901Whatisacomparatorcircuit?Acomparatorcircuitcomparestwovoltagesandoutputseithera1(thevoltageattheplusside;VDDintheillustration)ora0(thevoltageatthenegativeside)toindicatewhichislarger.Comparatorsareoftenused,forexample,tocheckwhetheraninputhasreachedsomepredeterminedvalue.WhatistheuseofLM339?LM339isusedinapplicationswhereacomparisonbetweentwovoltagesignalsisrequired.Inadditionwithfourofthosecomparatorsonboardthedevicecancomparefourpairsofvoltagesignalsatatimewhichcomesinhandyinsomeapplications.

BYM11-1000-E3/96-VISHAY

I.IntroductionThe74HC595isan8-bitserial-inorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.74HC595withthecharacteristicsofhighspeed,lowpowerconsumptionandsimpleoperation,canbeeasilyusedinMCUinterfacetodriveLEDoperation.ThisarticleintroducesthecircuitdesignofLEDdisplaydrivedby74HC595.CatalogI.IntroductionII.BasicDescription2.1LEDDisplay2.274HC595III.CircuitDesign3.1HardwareCircuit3.2DisplayDriverIV.ConclusionFAQOrdering&QuantityII.BasicDescription2.1LEDDisplayA7SegmentLEDDisplay,alsoknownasLEDdisplay,hasbeenwidelyusedinvariousinstrumentsbecauseofitslowprice,lowpowerconsumptionandreliableperformance.TherearemanytypesofLEDdriversonthemarket,andmostofthemhavemultiplefunctions,butthepriceiscorrespondinglyhigher.Ifusedinasimplesystemwithlowcost,itisnotonlyawasteofresources,butalsoincreasesthecostofproducts.Using74HC595chiptodriveLEDhasvariousdisadvantages.Highspeed,lowpowerconsumption,unlimitednumberofLEDs.ItcancontrolboththecommoncathodeLEDdisplayandthecommonanodeLEDdisplay.Thecircuitdesignedwith74HC595isnotonlysimple,butalsolowinpowerconsumptionandstrongindrivingability.Itisalowcostandflexibledesignscheme.2.274HC595The74HC595isan8-bitserial-in/serialorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.Boththeshiftandstorageregisterhaveseparateclocks.Thedevicefeaturesaserialinput(DS)andaserialoutput(Q7S)toenablecascadingandanasynchronousresetMRinput.ALOWonMRwillresettheshiftregister.DataisshiftedontheLOW-to-HIGHtransitionsoftheSHCPinput.ThedataintheshiftregisteristransferredtothestorageregisteronaLOW-to-HIGHtransitionoftheSTCPinput.Ifbothclocksareconnectedtogether,theshiftregisterwillalwaysbeoneclockpulseaheadofthestorageregister.Datainthestorageregisterappearsattheoutputwhenevertheoutputenableinput(OE)isLOW.AHIGHonOEcausestheoutputstoassumeahigh-impedanceOFF-state.OperationoftheOEinputdoesnotaffectthestateoftheregisters.Inputsincludeclampdiodes.ThisenablestheuseofcurrentlimitingresistorstointerfaceinputstovoltagesinexcessofVCC.Figure1.74HC595FunctionalDiagramFigure2.74HC595LogicSymbolIII.CircuitDesign3.1HardwareCircuitFigure3isadisplaypanelcircuitdesignedwithAT89C2051and74HC595interface.Figure3.CircuitofDisplayPanelTheP115,P116,andP117oftheP1portareusedtocontrolthedisplayoftheLED,andtheyareconnectedtotheSLCK,SCLKandSDApinsrespectively.Threedigitaltubesareusedtodisplaythevoltagevalue.Onthecircuitboard,LED3isonthefarleftandLED1isonthefarright.Whensendingdata,firstsendthedisplaycodeofLED3,andfinallysendthedisplaycodeofLED1.ThebrightnessoftheLEDiscontrolledbytheresistanceofPR1toPR3.2.2DisplayDriverUseDISP1,DISP2,andDISP3tostoredisplaydata.AftertheCPUinitializationiscomplete,calltheLRDISPsubroutinetocleartheregisterof74HC595.ThereisnoneedtocalltheclearsubroutinebeforecallingthedisplaysubroutineDISPLAY.Nowwritethetwosubroutinesasfollows.①CLRDISP:MOVR2,#24CLRBIT:CLRSCLKCLRCMOVSDA,CSETBSCLKDJNZR2,variable resistor symbolCLRBITRET②Display:CLRSLCKMOVR3,#3MOVR0,5srd#DISP3DISP1:MOVA,@R0MOVR2 ,air variable capacitor#8DISP2:CLRSCLKRLCAMOVSDA,CSETBSCLKDJNZR2,how to read resistorsDISP2DECR0DJNZR3 ,DISP1SETBSLCKRETIV.ConclusionItcanbeseenfromtheaboveexamplesthattherearenocomplicatedtechnicalproblemsinthedesignofhardwareandsoftwarewhen74HC595isusedtodesignLEDdrivercircuit.Inaddition,74HC595canbeusednotonlytodriveLEDdisplays,butalsotodrivelight-emittingdiodes.Each74HC595candrive8LEDssimultaneously.Thissolutionisidealwhenthevolumerequirementsoftheproductarenothighandwanttoreducethecost.FAQWhatis74HC595?74HC595isashiftregisterwhichworksonSerialINParallelOUTprotocol.Itreceivesdataseriallyfromthemicrocontrollerandthensendsoutthisdatathroughparallelpins.Wecanincreaseouroutputpinsby8usingthesinglechip.Whatisa74hc595n?8-bitShiftRegister74HC595NAshiftregisterisachipyoucanusetocontrolmanyoutputs(8here)atthesametimewhileonlyusingafewpins(3here)ofyourArduino.Howdoesashiftregisterwork?Shiftregistersholdthedataintheirmemorywhichismovedorshiftedtotheirrequiredpositionsoneachclockpulse.Eachclockpulseshiftsthecontentsoftheregisteronebitpositiontoeithertheleftortheright.How74HC595ShiftRegiesterworks?The595hastworegisters(whichcanbethoughtofasmemorycontainers),eachwithjust8bitsofdata.ThefirstoneiscalledtheShiftRegister.TheShiftRegisterliesdeepwithintheICcircuits,quietlyacceptinginput.Howdoesan8bitshiftregisterwork?TheSN74HC595Nisasimple8-bitshiftregisterIC.Simplyput,thisshiftregisterisadevicethatallowsadditionalinputsoroutputstobeaddedtoamicrocontrollerbyconvertingdatabetweenparallelandserialformats.YourchosenmicroprocessorisabletocommunicatewiththeTheSN74HC595Nusingserialinformationthengathersoroutputsinformationinaparallel(multi-pin)format.Essentiallyittakes8bitsfromtheserialinputandthenoutputsthemto8pins.

DescriptionLED,asthefirstbasicfunctiontobecompletedinMCUlearning,playsaveryimportantroleinMCUlearners,whichalsocalledmagiclampbyMCUlearners.IbelievethateveryoneseesmostandthesimplestLEDcircuitisthefigureshownbelow.Asshowninthefigure,notonlythecircuitissimple,butalsoitsoperationisverysimple.GiveselectricalleveltoI/OcorrespondingtoeightLEDs,andthecorrespondingLEDcanbeonoroff.Figure1.simpleLEDcircuitCatalogDescription74HC595Drives8BitsLEDSFAQOrdering&Quantity74HC595Drives8BitsLEDSButnotallLEDcircuitsaresosimple.Somecircuitswilluse74HC595chiptodrive8LEDsordrivethe8-bitdigitaltubesegmentcode,asshowninthefigurebelow.Figure2.74HC595drives8LEDsWhyisasimplecircuitsocomplicated?Thereasonisobvious.BeforetheeightLEDneedeightI/O,nowonlythreeI/OcandriveeightLED.Letsbrieflyintroduce74CH595anduseitsuccessfullytodriveeightLEDlights.The74HC595isan8-bitserial-inorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.Boththeshiftandstorageregisterhaveseparateclocks.Thedevicefeaturesaserialinput(DS)andaserialoutput(Q7S)toenablecascadingandanasynchronousresetMRinput.SIisitsserialdatainput.Q0toQ7aredataoutput.SCK,istheclockfortheshiftregister.The595isclock-drivenontherisingedge.Thismeansthatinordertoshiftbitsintotheshiftregister,theclockmustbeHIGH.Andbitsaretransferredinontherisingedgeoftheclock.RCK,isaveryimportantpin.WhendrivenHIGH,thecontentsofShiftRegisterarecopiedintotheStorage/LatchRegister;whichultimatelyshowsupattheoutput.Sothelatchpincanbeseenaslikethefinalstepintheprocesstoseeingourresultsattheoutput.SQHisserialdataoutput.Whatwewanttoachievenowistomovethe8-bitsdataofSIinto74HC595onebyoneundertheactionofSCKandRCKandpresenttheminparallelonQ0-Q7.Figure3.How74HC595ShiftRegisterworksWheneverweapplyaclockpulsetoa595,thebitsintheShiftRegistermoveonesteptotheleft.Belowisitscode.FAQWhatis74HC595?74HC595isashiftregisterwhichworksonSerialINParallelOUTprotocol.Itreceivesdataseriallyfromthemicrocontrollerandthensendsoutthisdatathroughparallelpins.Wecanincreaseouroutputpinsby8usingthesinglechip.Whatisa74hc595n?8-bitShiftRegister74HC595NAshiftregisterisachipyoucanusetocontrolmanyoutputs(8here)atthesametimewhileonlyusingafewpins(3here)ofyourArduino.Howdoesashiftregisterwork?Shiftregistersholdthedataintheirmemorywhichismovedorshiftedtotheirrequiredpositionsoneachclockpulse.Eachclockpulseshiftsthecontentsoftheregisteronebitpositiontoeithertheleftortheright.How74HC595ShiftRegiesterworks?The595hastworegisters(whichcanbethoughtofasmemorycontainers),eachwithjust8bitsofdata.ThefirstoneiscalledtheShiftRegister.TheShiftRegisterliesdeepwithintheICcircuits,quietlyacceptinginput.Howdoesan8bitshiftregisterwork?TheSN74HC595Nisasimple8-bitshiftregisterIC.Simplyput,thisshiftregisterisadevicethatallowsadditionalinputsoroutputstobeaddedtoamicrocontrollerbyconvertingdatabetweenparallelandserialformats.YourchosenmicroprocessorisabletocommunicatewiththeTheSN74HC595Nusingserialinformationthengathersoroutputsinformationinaparallel(multi-pin)format.Essentiallyittakes8bitsfromtheserialinputandthenoutputsthemto8pins.Whatisadigitaltube?Lightemittingdiodeconnectstheanodetogetherandthenconnectedtothepowerofpositiveiscalledcommonanodedigitaltube,lightemittingdiodeconnectedtothecathodeandthenconnectedtothepowerofthecathodeiscalledcommoncathodedigitaltube.Whatisthedifferencebetweenshiftregisterandcounter?Inashiftregister,theinputofelementNistheoutputofelementN-1,andallelementsusethesameclock.Inacounter,theinputofelementNistheinverseofitsoutput,andtheclockofelementN+1istheoutputofelementN.IDescriptionAD620isalow-power,high-precisioninstrumentationamplifier.BasedontheinformationprovidedbytheADcompany,thisblogintroducesthecharacteristicsandtypicalusageofAD620.Besides,thisblogalsointroducestheapplicationofAD620.Theapplicationsaremainlyaboutphotoelectricdetection,ultrasonictesting,etc.Figure1.AD620IDescriptionIIIntroductionIIIAD620PinoutandWorkingPrincipleIVAD620TypicalUsageVAD620Application5.1ApplicationinPhotoelectricDetection5.2ApplicationinUltrasonicTestingVIConclusionFAQOrdering&QuantityIIIntroductionAD620isalow-power,high-precisioninstrumentationamplifier.Anditcansettheamplificationfactorfrom1to1000withonlyanexternalresistor.Itissmallinsize,inan8-pinSOICorDIPpackage;thepowersupplyrangeis2.3V~18V;themaximumpowersupplycurrentisonly1.3mA.AD620hasgoodDCandACcharacteristics.Itsmaximuminputoffsetvoltageis50V,themaximuminputoffsetvoltagedriftis1V/℃,andthemaximuminputbiascurrentis2.0nA.WhenG=10,itscommon-moderejectionratioisgreaterthan93dB.Theinputvoltagenoiseisat1kHz,thepeak-to-peakvalueoftheinputvoltagenoiseis0.28Vintherangeof0.1Hz~10Hz,andtheinputcurrentnoiseisWhenG=1,itsgainbandwidthis120kHz,andthesettlingtimeis15s.Ingeneral,thecharacteristicsofAD620canbesummarizedasfollows:AD620canensuretheperformanceindicatorsrequiredforhigh-gainprecisionamplification.Forexample,lowoffsetvoltage,lowoffsetvoltagedrift,andlownoise,etc.;Withonlyoneexternalresistor,themagnificationcanbesetfrom1to1000;Smallsize,with8pins;Lowpowerconsumptionanditsmaximumsupplycurrentare1.3mA.IIIAD620PinoutandWorkingPrincipleThepinofAD620isshownasinFig.2,itsstructurediagramisshownasinFig.3.Figure2.AD620PinoutFigure3.AD620StructureDiagramAD620isamonolithicinstrumentamplifier.Itisdevelopedonthebasisoftheimprovementofthetraditionalthree-opamplifiercombination.TheinputtransistorsQ1andQ2providetheonlybipolardifferentialinput.Duetotheinternalsuperprocessing,itsinputoffsetcurrentis10timeslowerthannormal.ThroughthefeedbackoftheQ1-A1-R1loopandtheQ2-A2-R2loop,thecollectorcurrentsofQ1andQ2arekeptconstant.Thus,theinputvoltageisequivalenttothetwoendsoftheexternalresistorRg.AndthedifferentialamplificationfactorfromtheinputtotheA1/A2outputisG=(R1+R2)/Rg+1.TheunitygainsubtractorcomposedofA3eliminatesanycommon-modecomponents.Andthenitproducesasingle-channeloutputrelatedtothepotentialoftheREFpin.ThevalueofRgalsodeterminesthetransconductanceofthepreviousstageopamp.WhenRgdecreases,theamplificationfactorincreases.Andthetransconductancetotheinputtransistorgraduallyincreases.Thishasobviousadvantages:theincreaseintheamplificationfactorincreasestheopen-loopgain.Thus,theerrorrelatedtogainisreduced.Thegain-bandwidthproductdeterminedbyC1,C2andthepre-opamptransconductanceincreases.Thus,thefrequencyresponseisimproved.Theinputvoltagenoiseismainlydeterminedbythecollectorcurrentoftheinputtransistorandthebaseresistance.Andtheinputvoltagenoiseisreducedto.TheinternalgainresistorsR1andR2areaccuratelydeterminedas24.7k.Inthiscase,theoperationalamplifiergainisaccuratelydeterminedbyRg.G=49.4k/Rg+1orRg=49.4k/(G-1)IVAD620TypicalUsage(1)Theinputbiascurrentisthecurrentrequiredtobiastheinputtransistoroftheopamp,anditmusthaveareturnloop.Therefore,whenamplifyinganAC-coupledsignalsourcelikeatransformer,eachinputpointmusthaveaDCpathtoground.AsshowninFigure4-6.Figure4.BiasCurrentLoopwithTransformerCoupledInputFigure5.BiasCurrentLoopforThermocoupleInputFigure6.BiasCurrentLoopWhenACCoupledInput(2)Allinstrumentamplifiersrectifythesignaloutsidethechannel.Ifasmallsignalisamplified,thisrectifiedvoltagebecomesaDCoffsetvoltage.ThestructureofAD620allowsafirst-levelfiltertobeinsertedbetweenthebaseandemitteroftheinputtransistortofilteroutunwantedrectifiedsignals,asshowninFigure5.RC=1/2f,fisgreaterthanorequaltothebandwidthofAD620,C150pF.Figure7.PrimaryFilterPrincipleDiagram(3)TheoutputvoltageofAD620isrelatedtothereferenceterminal.ConnectingtheREFterminaltoanappropriategroundingpointcansolvemanygroundingproblems.Manydataacquisitionsystemsseparatetheanaloggroundfromthedigitalground.Howcome?Justaimingtoisolatethelow-levelanalogsignalfromthenoisydigitalenvironment.Thegroundingprincipleisasfollows:eachindependentgroundloopminimizesthecurrentflowingfromthesensitivepointtotheground.Thesegroundloopsmustbeconnectedtogetheratsomepoint,usuallyontheADC.LetstakealookatFigure7.Thereferenceterminal5oftheAD620,thegroundterminalofthesample-and-holdAD585.Andthegroundterminaloftheanalogpowersupplyarerespectivelyconnectedtotheanaloggroundterminaloftheanalog-to-digitalconverterAD574A.Thegroundterminalofthedigitalpowersupplyisconnectedwiththedigitalgroundoftheanalog-to-digitalconverterAD574A.Finally,theanaloggroundanddigitalgroundareconnectedtotheAD574A.Inmanyapplications,shieldedcablesareoftenusedtoreducenoiseinterferenceattheinput.Properdrivetotheshieldcanreducethedifferentialphaseshiftcausedbycablecapacitanceandstraycapacitance.AndensurethattheACcommon-moderejectionratiodoesnotdrop.Figure8showsthedifferentialshielddriveconnection.Figure9showsthecommon-modeshielddriveconnection.Figure8.DifferentialShieldDriveFigure9.CommonModeShieldDriveVAD620Application5.1ApplicationinPhotoelectricDetectionPhotoelectricdetectioniswidelyusedintheindustry.Theprincipleofdesigningaphotoelectricdetectionsystemistoreducethetotalsystemnoisetoaminimum.Thenoiseofthesystemmainlyincludesdetectornoise,resistancenoise,andoperationalamplifiernoise.Becausetheyareindependentofeachother,thetotalnoisecanbeexpressedasUn(T)=[Un2(D)+Un2(L,F)+Un2(A)]1/2Intheformula:Un2(D)Detectornoisevarieswithdifferentphotodetectors.Theappropriatedetectorshouldbeselectedaccordingtothesystemrequirements;Un2(L,F)Loadresistancenoise;Un2(A)Opampnoise.ThenoiseofAD620isverysmall.Therefore,itisoftenusedasthepre-opamplifierofthephotoelectricdetectioncircuit.Takethephotodiodeasthedetectorasanexampletoillustrate.Here,supposethecurrentofthephotodiodeisID,thenID=ISC+IdarkIntheformula:ISCPhotocurrent.Itisproportionaltothelightintensity,whichistheeffectiveinformationdetected;IdarkDarkcurrent.ItconsistsofthecurrentonthesurfaceofthediodeandtheusualPNjunctioncurrent.Itbelongstoinvalidinformationinthesystem.Weneedtoeliminatetheinfluenceofdarkcurrent.TwodiodesD1andD2withthesameperformanceandtworesistorsR1andR2withtheresistancevalueofRareselectedtoformabridge.AsshowninFigure10.Figure10.PhotoelectricDetectionPreamplifierCircuitWhenD1haslightandD2hasnolight,theinputvoltageatbothendsoftheop-ampis(ISC+Idark)-R1-Idark-R=ISC-R1.Itisonlyrelatedtothephotocurrent,thuseliminatingtheinfluenceofthedarkcurrent.5.2ApplicationinUltrasonicTestingInthefieldofultrasonictesting,especiallywhenultrasonicwavespropagateinanon-uniformandattenuatedmedium,theechoafterencounteringtheinterfaceisveryweak.Ifageneralop-ampisusedforpre-processing,thenoiseisoftenlargeandeffectivesignalscannotbeobtained.ChoosingAD620asthepre-amplifiercircuithasasimpleconnectionandlownoise.AsshowninFigure11.Figure11.UltrasonicDetectionReceivingFrontCircuitVIConclusionAD620isahighprecisioninstrumentationamplifier.Intheapplication,wealsoneedtopayattentiontopreventtheblockageoftheamplifier.IfastrongDCsignalissuperimposedontheweaksignal,wemustsetupaseparationcircuit.Inthisway,theDCsignalcanbeseparated.FAQWhatisAD620?AD620isalow-cost,high-precisioninstrumentationamplifier.Itonlyrequiresanexternalresistortosetthegain.Thegainrangeis1to10,000.CanIchangeAD620toAD623whenmakingMCUproducts?BothAD620andAD623aresingleinstrumentationamplifiers,andthepinarrangementisexactlythesame.Themaindifferenceis:AD620mustusepositiveandnegativepowersupplies,AD623canbeapositiveandnegativepowersupplyorasinglepowersupply.IftheoriginalboardisAD620,youcanreplaceitwith623;iftheoriginalboardisAD623,youmaynotbeabletoreplaceitwith620(itdependsonwhetherthepowersupplyoftheoriginalboardcircuitisdualpowersupplyorsinglepowersupply).AfterreplacingAD620andAD623insingle-chipproducts,theprogramcanworknormallywithoutmodification.WhatisthedifferencebetweenAD620BRandAD620AN?Theirpackagesaredifferent.WhatistheoutputresistanceofAD620?Howtoadjustit?AD620isakindoflowpowerconsumptioninstrumentamplifier,itsoutputresistanceisabout10K,thisistheinherentcharacteristicofthischip,generallyitisdifficulttoadjust.Ifyouhaverequirementsforoutputresistance,youcangenerallyuseanexternalcircuittosolveit.IsAD620apositivephaseamplificationorareversephaseamplification?AD620isaninstrumentamplifier,theoutputvoltageis[(Vin+)-(Vin-)]*gain.Ifthedesiredsignalis(Vin+)-(Vin-),thegainispositive,whichisequivalenttopositiveamplification.Conversely,ifthedesiredsignalis(Vin-)-(Vin+),thegainisequivalenttonegative,whichisequivalenttoreverseamplification.Whatisaninstrumentationamplifier?Instrumentationamplifier,animprovementofthedifferentialamplifier,hasaninputbuffer,doesnotrequireinputimpedancematching,sothattheamplifierissuitableformeasurementandelectronicinstruments

IIntroductionHere,youcanlearnabouttheAD620instrumentamplifiercircuit.Besides,youcanalsobrowseAD620mainfeatures,workingprinciples,andapplications.Thisbloggenerallydiscussesthefollowing3basicquestions:1.Whatisaninstrumentationamplifier;2.Howdoesitwork;3.Howandwheretouse.Figure1.AD620CatalogIIntroductionIIDescriptionIIIAD620TechnicalIndicatorsIVAD620WorkingPrincipleVAD620ApplicationVIConclusionFAQOrdering&QuantityIIDescriptionOperationalamplifiershaveevolvedoverthedecadesandasaresult,thereisawidevarietyofthem.Theycanbeeasilycategorizedaccordingtotheirapplicationrequirements.Themaincategoriesincludegeneral-purpose,low-voltage,low-power,high-speed,andhigh-precisiontypes.Inrecentyears,applicationssuchasconsumerelectronics,communication,andnetworkinghavebeendevelopingcontinuously.Andtheseconstantlydevelopingindustriesalsoputforwardnewtechnicalrequirementsforop-ampproducts.AD620instrumentamplifieristheproductofADcompany.Duetoitssupertechnology,AD620hasthefollowingcharacteristics:1.3mAMaximumWorkingCurrent5VInputOffsetVoltage1V/℃InputOffsetDriftMaximum93dBCommonModeRejectionRatioAdjustableGainRangeEasytoAdjustandLowNoise.AndwhycanAD620becomeanindustry-standardhigh-performance,low-costinstrumentationamplifier?ThatsbecausethecoreofAD620isathree-stageop-ampcircuit,whichhasahighcommon-moderejectionratio,goodtemperaturestability,wideamplificationband,andlownoise.Andithasthecharacteristicsofhighaccuracy,easyuse,andlownoise.sothisisalsothereasonwhyAD620canbesopopular.IIIAD620TechnicalIndicatorsThemaintechnicalindicatorsofAD620areasfollows:Bandwidth800MHzOutputpower2.4mWPowergain120dBWorkingvoltage15VStaticpowerconsumption0.48mWInoltage60VConversionrate1.2V/SPackageformDIP8Operatingtemperaturerange-55℃~+125℃IVAD620WorkingPrincipleThefunctionalstructureoftheAD620amplifierisshowninFig.2.Figure2.AD620FunctionalBlockDiagramDoyouknowwhatthecharacteristicsofthisamplifierare?Theansweris:differentialinput,asingle-endedoutput.ThevoltagegaincanbedeterminedbyaresistorRG.Thegainsareadjustable,whichsolvestheproblemofconnectingthesubsequentloadtotheground.Besides,A1andA2formadifferentialinputandadifferentialoutputwithin-phasehighinputimpedanceandundertakeallgainamplificationtasks.Becausethecircuitstructureissymmetrical,whichmeanswhenthegainchanges,theinputimpedancedoesnotchange.ThefeedbackresistanceRl=R2=24.7k.Thecommon-modegain,offset,drift,andothererrorsoftheamplifiersA1andA2aremutuallycompensated.ThegainofthelatterstageA3is1,whichhasahighercommon-moderejectionratioandanti-interferenceability.AD620isamonolithicintegratedamplifier.Anditisdevelopedonthebasisoftheimprovementofthetraditionalthree-opamplifiercombination.AsshowninFigure2,theinputtransistorsQ1andQ2providetheonlybipolardifferentialinput.Duetotheinternalultra-processing,itsinputoffsetcurrentis10timeslowerthanthegeneralcase.ThroughthefeedbackoftheQ1-A1-R1loopandtheQ2-A2-R2loop,theintegratedpolecurrentofQ1andQ2iskeptconstant.SotheinputvoltageisequivalenttothetwoendsoftheexternalresistorRG.ThedifferentialamplificationfactorfrominputtoA1/A2outputisG=(R1+R2)/RG+1.TheunitygainsubtractorcomposedofA3eliminatesanycommon-modecomponents.Thereby,itproducesasingle-channeloutputrelatedtothepotentialoftheREFpin.Figure3.AD620SowhataboutRG?ThevalueofRGalsodeterminesthetransconductanceofthepreviousstageop-amp.WhenRGdecreases,themagnificationincreases.WhenRGdecreases,thetransconductancetotheinputtransistorgraduallyincreases.Thishasthefollowingtwoobviousadvantages:First,theincreaseintheamplificationfactorincreasestheopen-loopgain.Therebyreducingthegain-bandwidthproductandincreasingthefrequencyresponse;Second,itismainlydeterminedbytheinputtransistorcollectorcurrentandbaseresistance.ByaccuratelycorrectingthevalueoftheinternalgainresistorsR1andR2to24.7k,wecanmaketheoperationalamplifiergain(derivedbycalculation)accuratelydeterminedbyRG:G=49.4k/RG+1orRG=49.4k/(G-1)Figure4.AD620CircuitStructureDiagramRGistheexternalgainadjustment.Tomeettherequiredamplificationfactor,wecanconnectthishigh-precisionresistancebetweenpin1and8.ByusingtheamplifierAD620,thegainerrorcanbelessthan0.01%,andthenon-linearityislessthan0.002%.Fromtheapplicationpointofview,AD620isparticularlysuitableforapplications.Suchassensorinterface,ECGmonitor,precisionvoltagecurrentconversionandotherapplications.Ifweanalyzethecircuittechnologyperformance,wewilladeeperunderstandingofAD620.Thatis,AD620isactuallyalow-power,high-precisioninstrument,broadbandintegratedoperationalamplifier.VAD620ApplicationInstrumentationamplifiersaresometimesmisunderstoodbypeople.Here,weneedtopointout2ideas:First,notallamplifiersusedforinstrumentationareinstrumentationamplifiers;Second,allinstrumentationamplifiersarebynomeansonlyusedforinstrumentation.Instrumentationamplifiersareusedinmanyfields.Frommotorcontroltodataacquisitionandautomotivesystems.Instrumentationamplifierisaclosed-loopgainunit.Andwithdifferentialinputandsingle-endedoutputrelativetothereferenceend.Inmostcases,theimpedanceofthetwoinputendsoftheinstrumentationamplifierisbalanced.Theresistanceisveryhigh,anditstypicalvalueis109.Theinputbiascurrentisalsoverylow,typically1nAto50nA.Liketheoperationalamplifier,itsoutputimpedanceisverylow,usuallyonlyafewmilliohmsinthelowfrequencyrange.Theclosed-loopgainofanoperationalamplifierisdeterminedbytheexternalresistance.Theexternalresistanceisconnectedbetweenitsinvertinginputandoutput.Therearedifferencesbetweentheinstrumentamplifierandtheamplifier.Theinstrumentamplifierusesaninternalfeedbackresistornetwork,whichisisolatedfromitssignalinput.Toapplyinputsignalstothetwodifferentialinputterminalsoftheinstrumentationamplifier.Thegaincaneitherbepresetinternallyorsetbytheuser.Throughapinconnectedtoaninternalorexternalgainresistor,whichisalsoisolatedfromthesignalinputterminal.Figure5showsablockdiagramofadifferentialamplifier.Figure5.DifferentialAmplifierICThistypeofICisaspecial-purposeinstrumentationamplifier.Anditwhichusuallyconsistsofasubtractoramplifierfollowedbyanoutputbuffer(perhapsone-stagegain).ThefourresistorsusedforthesubtractorareusuallyinsidetheIC,sotheycanbepreciselymatchedtoachieveahigherCMR.Manydifferentialamplifiersaresuitableforapplications.Wherethecommon-modevoltageandsignalvoltagemayeasilyexceedthesupplyvoltage.Thesedifferentialamplifiersusuallyusehigh-valueinputresistorstoattenuatethesignal.Generallyspeaking,instrumentationamplifiersanddifferentialamplifiersareusedinthefollowingranges:DataAcquisitionThemainpurposeoftheinstrumentationamplifieristoamplifytheweaksignaloutputbythesensorinanoisyenvironment.Amplificationofsignalsfrompressuresensorsortemperaturesensorsiscommon.Commonbridgeapplicationsincludestrainforceandweightmeasurement.MedicalInstrumentsInstrumentationamplifiersarewidelyusedinmedicalequipment.Suchaselectrocardiographsandelectroencephalographs,bloodpressuremonitors,anddefibrillators.Thedifferentialamplifierofmonitoringandcontrolelectronicscanbeusedtomonitorthevoltageandcurrentinthesystemandtriggerthealarmsystemwhenthenormalvalueisexceeded.Becausedifferentialamplifiershavetheabilitytosuppresshighcommon-modevoltages,theyareoftenusedinsuchapplications.Figure6.ElectrocardiographSoftwareProgrammableApplicationsToallowsoftwaretocontrolthehardwaresystem,wecanturntoinstrumentationamplifiers.Instrumentationamplifierscanbeusedonchipswithsoftwareprogrammableresistors.AudioApplicationsBecauseinstrumentationamplifiershavehighCMR,theyareusedforaudio(e.g.microphonepreamplifiers)toextractweaksignalsinnoisyenvironments.Also,itcanbeusedtominimizetheoffsetcausedbygroundloopsVoltageandnoise.High-speedSignalConditioningDuetotheincreasedspeedandaccuracyrequirementsoftodaysvideodataacquisitionsystems,thedemandforbroadbandinstrumentationamplifiersisincreasing.EspeciallyinthefieldofCCDimagingequipmentthatrequiresoffsetcorrectionandinputbuffering.Inthisfield,doublecorrectionsamplingtechnologyisusuallyusedtocorrecttheCCDimage.Generallyusetwosample-and-holdamplifierstomonitortheimageandreferencelevel,andsendthesignalvoltagetoaninstrumentationamplifiertoprovideaDCcorrectionoutput.Figure7.CCDCameraVideoApplicationsHigh-speedinstrumentationamplifiersareusedinmanyvideoandcableradiofrequency(RF)systemstoamplifyorprocesshigh-frequencysignals.PowerControlApplicationsInstrumentationamplifierscanalsomonitorthemotor(monitoringandcontrollingthemotorsspeed,torque,etc.)bymeasuringthemotorsvoltage,currentandthephaserelationshipofthethree-phaseACmotor.Thedifferentialamplifierisusedwhentheinputsignalvoltageexceedsthepowersupplyvoltage.VIConcusionGenerallyspeaking,high-speedoperationalamplifiersaremainlyusedincommunicationequipment,videosystems,andtestandmeasurementinstruments.Advancedapplicationsintestandmeasurement,communications,medical,imagingandotherfieldsarethemaindrivingforcestoimproveamplifierperformance;DSLandconsumervideoapplicationsareitslargestmarkets.FAQWhatisAD620?AD620isalow-cost,high-precisioninstrumentationamplifier.Itonlyrequiresanexternalresistortosetthegain.Thegainrangeis1to10,000.CanIchangeAD620toAD623whenmakingMCUproducts?BothAD620andAD623aresingleinstrumentationamplifiers,andthepinarrangementisexactlythesame.Themaindifferenceis:AD620mustusepositiveandnegativepowersupplies,AD623canbeapositiveandnegativepowersupplyorasinglepowersupply.IftheoriginalboardisAD620,youcanreplaceitwith623;iftheoriginalboardisAD623,youmaynotbeabletoreplaceitwith620(itdependsonwhetherthepowersupplyoftheoriginalboardcircuitisdualpowersupplyorsinglepowersupply).AfterreplacingAD620andAD623insingle-chipproducts,theprogramcanworknormallywithoutmodification.WhatisthedifferencebetweenAD620BRandAD620AN?Theirpackagesaredifferent.WhatistheoutputresistanceofAD620?Howtoadjustit?AD620isakindoflowpowerconsumptioninstrumentamplifier,itsoutputresistanceisabout10K,thisistheinherentcharacteristicofthischip,generallyitisdifficulttoadjust.Ifyouhaverequirementsforoutputresistance,youcangenerallyuseanexternalcircuittosolveit.IsAD620apositivephaseamplificationorareversephaseamplification?AD620isaninstrumentamplifier,theoutputvoltageis[(Vin+)-(Vin-)]*gain.Ifthedesiredsignalis(Vin+)-(Vin-),thegainispositive,whichisequivalenttopositiveamplification.Conversely,ifthedesiredsignalis(Vin-)-(Vin+),thegainisequivalenttonegative,whichisequivalenttoreverseamplification.Whatisaninstrumentationamplifier?Instrumentationamplifier,animprovementofthedifferentialamplifier,hasaninputbuffer,doesnotrequireinputimpedancematching,sothattheamplifierissuitableformeasurementandelectronicinstrumentsIntroductionInrecentyears,withthecontinuousdevelopmentofnewtechnologies,storagebatteriesasapowersourcenotonlyplayanimportantroleintransportation(railroad,subway,ship),powergeneration,communications,aerospace,chemical,traditionalautomobilesandotherindustries.Inaddition,batterieshavealsobeguntobeusedinthefieldsofelectricvehicles(EV)andhybridelectricvehicles(HEV)aspowersourcesorpowerauxiliarypowersources.Doyouknowwhatare2featuresofbatteriescomparedwithdisposablerechargeablebatteries?Thatismultiplerecyclingandhighefficiencyandenergysaving.Whenthecarisnotstarted,itmustrelyonthebatterytosupplypowertothestarteruntilitdrivestheenginetorotate.Whenthebatteryvoltageisinsufficientorthebatteryisdamaged,itisdifficulttoprovidesufficientpower,thuscausingtheenginetofailtorun.Therefore,thisblogproposesthedesignofalow-batteryalarmsystemforcarbatteriesbasedonLM741.Ingeneral,whenthebatteryvoltagedropstoacertainlimit,itwillsendoutareminder.Theprincipleofthereminderisthatthecircuitjudgeswhetherthebatteryisworkingnormallybyinstallingasoundandlightsignalalarmsystem.Inthisway,wecanrechargeourcarorreplacethebatteryintime.CatalogIntroductionCatalogIDescriptionofLM741IIDesignoftheSystemIIICircuitDesign3.1SystemHardwareCircuitDesign3.2ReferencePowerSupplyCircuit3.3SamplingCircuit3.4OutputCircuit3.5AlarmPrinciple3.6WiringDiagramoftheSystemIVTestResultsoftheSystemFAQOrdering&QuantityIDescriptionofLM741TheLM741seriesaregeneral-purposeoperationalamplifiers.Itisintendedforawiderangeofanalogueapplications.Thehighgainandwiderangeofoperatingvoltageprovidesuperiorperformanceinintegrator,summingamplifier,andgeneralfeedbackapplications.LM741hasbothinvertinginputsandnon-invertinginputs.Whenthevoltageofthenon-invertinginput(+)ishigherthanthevoltageoftheinvertinginput(-),theoutputofthecomparatorishigh.Ifthevoltageattheinvertinginput(-)ishigherthanthenon-invertingterminal(+),theoutputislow.Theoutputoftheoperationalamplifieristheproductofgainandinputvoltage.IIDesignoftheSystemThelowbatteryalarmsystemismainlycomposedofreferencepowersupplycircuit,samplingcircuit,voltagecomparatorcircuitandoutputcircuit.Thereferencepowersupplycircuitconsistsofavoltageregulatorandacurrentlimitingresistor,whichisaddedtotheinvertinginputofthevoltagecomparatorandprovidesareferencevoltageforit.Thesamplingcircuitiscomposedoftworesistorsinseriestoformaseriesvoltagedivider,whichisusedastheinputsignalofthewholecircuit,andapartofthebatteryvoltageiscomparedwiththereferencevoltage.Thevoltagecomparatorcircuitjudgeswhethertheoutputishighlevelorlowlevelbycomparingthevoltageofthereferencepowersupplycircuitandthevoltageofthesamplingcircuit.Theoutputcircuitjudgeswhetherthelight-emittingdiodeisintheconductingstatebythereceivedoutputvoltagefromvoltagecomparator,therebygivinganalarmsignaltoindicatethebatterypoweristoolow.Figure1.StructureoftheSystemIIICircuitDesign3.1SystemHardwareCircuitDesignThehardwarecircuitoflowbatteryalarmsystemisshowninFigure2.ThesystemmainlyincludesvoltagecomparatorLM741,resistor,voltageregulatorandLED.Figure2.HardwareCircuit3.2ReferencePowerSupplyCircuitThereferencepowersupplycircuitconsistsofcurrentlimitingresistorR2andvoltageregulatorVDZ.ThissystemtakesthestablevoltageoftheregulatorasthereferencevoltageofthecomparatorLM741,andconnectsittotheinvertinginputoftheLM741.R2=100k.Thestablevoltageis5V.3.3SamplingCircuitR1andR3areconnectedinseriestoformasamplingcircuit,whichisconnectedtothein-phaseinputterminalofLM741.TheresistancevaluesofR1andR3areequal,taking100ktoformseriespartialvoltage.Theintermediatepointisthesamplingvoltage,thatis,takingpartofthebatteryvoltageasthedetectionvoltage,i.e.theinputvoltage.3.4OutputCircuitTheoutputcircuitconsistsofR4andLED.R4=1K,whichcanlimitthecurrent.AccordingtothevoltagevalueattheoutputofthevoltagecomparatortodeterminedwhethertheLEDisonoroff.3.5AlarmPrincipleWhenthebatteryvoltageishigherthan10V,thatis,thevoltageofsamplingcircuitexceeds5V,theinputsignalvoltageishigherthanthereferencevoltage,thenLM741outputshighlevel,andtheoutputvoltageisbatteryvoltage(10~12V).ItcanbeseenfromFigure4thatthepotentialofpin6ishigherthanthepotentialofpin7.LEDdonotemitlightbecauseofthereversevoltage.Thisindicatesthatthebatteryvoltageisnormalandthealarmfunctionisnotactivated.Whenthebatteryvoltageislowerthan10Vandtheinputsignalvoltage(5V)islowerthanthereferencevoltage,theLM741outputsalowlevel,thatis,theoutputvoltageiszero.Atthistime,thepotentialofpin7ishigherthanthepotentialofpin6,theLEDisturnedonduetotheforwardvoltage.Andthelightindicatesthatthebatterypoweristoolow.Thealarmfunctionisactivated.3.6WiringDiagramoftheSystemFigure3showsthewiringstructureoflowbatteryalarmsystem.Theautomobilebatteryisconnectedtothevoltagecomparisondevicethroughthecarkeyswitch,andprovidespowerfortheautomobilecircuitload(lightingsystem,instrumentsystem,etc.)Whenthebatteryvoltageisnormal,theloadvoltageisnormal.Andthevehiclecanstartnormally.Theinstrumentsystemcandisplayandworknormally.Whenthebatteryvoltageistoolow,thevoltagecomparisondevicewillsendoutalightalarmsignal.Atthesametime,ifthepowersupplyvoltagecannotreachtherequiredvoltagelevelofthesystem,thecorrespondinglighting,instrumentandothersystemswillnotoperate.Figure3.WiringDiagramoftheSystemIVTestResultsoftheSystemItcanbeseenfromtable1thatwhenthebatteryvoltageislowerthan10V,thealarmindicatorison;whenthebatteryvoltageishigherthan10V,thealarmindicatorisoff.Therefore,thecircuitcangiveanalarmwhenthebatteryvoltageislowerthan10V,andstopwhenthebatteryisrechargedtoabove10Vagain.Thealarmsystemdoesnotworkwhentheoutputvoltageofthebatteryisabove10V.Itfullyshowsthatthedesignschemeofthecircuitiscorrectandfeasible.TestResultsoftheSystemBatteryvoltage(V)BatteryvoltagestatusAlarmindicatorstatus6.8toolowon8.1lowon9.6lowon10.3(Aftercharging)normaloff12.8(Aftercharging)normaloff13.6(Aftercharging)toohightoffFAQWhatislm741opamp?AnLM741operationalamplifierisaDC-coupledhighgainelectronicvoltageamplifier.Ithasonlyoneop-ampinside.AnoperationalamplifierICisusedasacomparatorwhichcomparesthetwosignal,theinvertingandnon-invertingsignal.WhyOpampiscalled741?The741OpAmpICisamonolithicintegratedcircuit,comprisingofageneralpurposeOperationalAmplifier.ItwasfirstmanufacturedbyFairchildsemiconductorsintheyear1963.Thenumber741indicatesthatthisoperationalamplifierIChas7functionalpins,4pinscapableoftakinginputand1outputpin.Howdoesa741opampwork?ThemostcommonOp-Ampisthe741anditisusedinmanycircuits.TheOPAMPisaLinearAmplifierwithanamazingvarietyofuses.Itsmainpurposeistoamplify(increase)aweaksignal-alittlelikeaDarlingtonPair.TheOP-AMPhastwoinputs,INVERTING(-)andNON-INVERTING(+),andoneoutputatpin6.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhydoestheIC741requiredualpowersupply?Operationalamplifiershavetwopowersupplyrailsbecausetheyusuallyneedtoswingbipolar-outputvoltagesthatgoeitherpositiveornegativeinresponsetothenormalrangeofinputsignals....Withoutthedualsuppliestheoutputsignalwouldclipatthegroundpotential.HowdoIcheckmy741IC?Testinga741ICThecircuitiscommonlycalledasvoltagefollower.Avoltageisappliedtopin3oftheop-ampthroughthevariableresistor(10K).AllweneedtodoistoverifywhetherthevoltagesV1andV2areexactlysameornot.Checkthemusingamulti-meter.WhatisIC741?Anopampisacomplexelectronicdevice,whichconsistsofresistors,capacitors,transistorsanddiodes.Itiscommerciallyavailableinintegratedcircuitform.MostcommonlyavailableandusedopampICisIC741.TheIC741isasmallchip.Itcompriseseightpins.Whatisgainbandwidthproductof741?Gain-BandwidthProduct:ForanOp-Ampthegain,Gisdefinedasthegainwhenasignalisfeddifferentiallyintotheop-ampandnofeedbackloopispresent....ItisgenerallygiveninV/s,andforthe741op-ampissomethingcloseto1v/s.WhatarethefeaturesofIC741?Shortcircuitandoverloadprotectionprovided.Intheory,thedcoutputvoltagewillbezeroifboththeinputsofthe741ICareconnectedtotheground.Lowpowerconsumption.Largecommonmoderejectionratio(CMRR)anddifferentialvoltageranges.Noexternalfrequencycompensationisrequired.Whichop-amp(LM356orLM741)isthebetterchoiceforhigherfrequencyapplications?Um,theLM356isanaudiopoweramplifierwitha300KHzbandwidth.TheLM741isanoperationalamplifierwithatypicalunitygainbandwidthof1MHz.Inotherwords,theyareentirelydifferentsortsofthingsandnotatallinterchangeable.Neitherisverygoodathigherfrequencies.YoumightbethinkingoftheLF356,whichisaJFETinputoperationalamplifierwithaunitygainbandwidtharound5MHz.MuchbetterpartinalmosteverydimensionthantheLM741.CanweuseanLM324insteadofanLM741forconstructinganop-ampintegrator?Yes.Itwilllikelyperformslightlybettertooasithasaslightlybetterspecification(frequency,slewrate,etc),plusyougetfouridenticalopampsinasingle14pinpackage.

IntroductionTheLM386isapoweramplifierdesignedforuseinlowvoltageconsumerapplications.Thegainisinternallysetto20tokeepexternalpartcountlow,buttheadditionofanexternalresistorandcapacitorbetweenpins1and8willincreasethegaintoanyvaluefrom20to200.Theinputsaregroundreferencedwhiletheoutputautomaticallybiasestoone-halfthesupplyvoltage.Thequiescentpowerdrainisonly24mWwhenoperatingfroma6Vsupply,makingtheLM386idealforbatteryoperation.CatalogIntroductionCatalogIHowdoesLM386InternalCircuitWork?1.1Inputstage1.2VoltageAmplifierstage1.3Outputstage1.4FeedbackNetworkIILM386ApplicationCircuit2.1CircuitofInfraredalarm2.2CircuitofAutomobileVoiceHorn2.3CircuitofMicrocomputerStereoPowerAmplifierFAQOrdering&QuantityIHowdoesLM386InternalCircuitWork?TheprincipleofLM386internalcircuitisshowninthefigure.Theinternalcircuitisbasedonatypicalaudiopoweramplifierconfiguration,oftenreferredtoasLintopology.LM386internalcircuitisdividedintoinputstage,voltageamplifierstage(VAS),outputstage(OPS)andfeedbacknetwork.Figure1.LM386InternalCircuit1.1InputstageThefirstmoduleisthePNPemitterfolloweramplifier(Q1,Q3).ItsetstheinputimpedanceanddefinestheDCoperatingpointtoraisetheinputvoltagefromtheground,sothecircuitwillacceptthenegativeinputsignalto-0.4V.Both50Kinputresistors(R1,R3)haveestablishedpathstothebasecurrentground,andtheinputsneedtobecoupledtoavoidinterferingwiththeinternalbias.Sotheinputimpedanceisdeterminedbytheseresistorsandissetto50K.Analysisofvoltagegain:Thegainoflongtailpair(Q2,Q4)ofdifferentialamplifierisregulatedbytwogainsettingresistors1.35k+150(R5+R5).Externalpins1and8canadjustthegainfrom20(minimum)to200(maximum).Thevoltagegaincanbecalculatedunderstaticconditions(withoutinputsignalapplied)asfollows:Figure2.AnalysisofLM386voltagegainThevoltage(vdiff)atbothendsofR4andR5isonlythedifferentialinputvoltage(VIN),becausethebaseemittervoltagedropofPNPtransistors(Q1,Q2,Q3andQ4)onbothsidesofLTPisthesame.ThecurrentmirrorformedbyQ5andQ6producesequalcurrentonbothsidesoftheLTP.ThecurrentismarkedasI.Duetothecurrentmirror,thecurrentintensitythroughR8isequalto2I,whileignoringthecurrent(i7)throughthetwo15Kresistors(R6,R7).thesetworesistorshavealargerimpedancecomparedtotherestofthecircuit,thereby:Inthefigureabove,itiseasytoseethatifi7=0,then:Theformulacanalsoberewritteninamoregeneralway:Z1-5andZ1-8aretheimpedancebetweenthecorrespondingpins.Withoutanyexternalcomponents,thegainisGV=2x15k/(150+1350)=20(26dB).Useacapacitor(orshortcut)betweenpin1and8,thenitsgainofGV=2x15k/150=200(46db).1.2VoltageAmplifierstageThecommonemitteramplifier(Q7)amplifiesthelowamplitudeinputsignaltotheappropriateleveldirectlycoupledtotheoutputstage.1.3OutputstageItisclassABpoweramplifier,thatis,push-pullconfiguration.Eachtransistoramplifiesitscorrespondinghalfwave.BecausethegaindifferencebetweenQ9andQ10ofPNPtransistorsisinacompoundPNPtransistorconfiguration,TOTAL=Q9XQ10.Dividercompensation:DiodesD1andD2areusedtocompensateforcrossdistortion.Infact,inapush-pulltopology,thetransistordoesnotstartconductinguntiltheinputsignalbeginstoexceeditsforwardvoltage(Vbe).Theforwardvoltage(VBE)isthevoltageatthebaseemitterjunction(usuallyabout0.6V).Inordertooffsettheminimumconductionlimit(Vbe)ofthetransistors,theyneedtobebiasedsothattheiridlingvoltagewillneverbelowerthantheforwardvoltage(Vbe).Acertainamountofcurrent(calledabiascurrent)willcontinuouslyfeedintothebaseofthetransistortoensurethattheymaintainthesacrificialefficiencyofconduction.Itisprovedthatusingdiodesisoneofthebestsolutions.Itprovidesatemperature-dependentpressuredrop.Andbymatchingthethermalcoefficienttothetransistor,thebiascurrentcanbekeptfairlystable.Ifaccurateheattracingisrequired,installthediodesonthesameheatsinkasthepowertransistor.Sinceonediodeisusuallynotenough,amplifiersusuallyusemultiplediodejunctions1.4FeedbackNetworkAnegativefeedbackisappliedfromtheoutputtotheemitterQ4viatheresistorR8.ThefunctionoftheDCfeedbackistostabilizetheoutputDCbiasvoltagetohalfofthesupplyvoltage.ThefunctionsofDCfeedbackareasfollows:IfforsomereasonVOincreases,thecorrespondingcurrentincrementwillflowthroughR8andintotheemitterofQ4.Therefore,theincreaseofcollectorcurrentofQ4leadstothepositiveincreaseofbasevoltageofQ7.ThisleadstoanincreaseinthecollectorcurrentofQ7,whichreducesthebasevoltageofQ7,thusreducingVo.IILM386ApplicationCircuit2.1CircuitofInfraredalarmFigure3.CircuitofInfraredalarmFigure3showsthecircuitofinfraredalarm.ThecircuitiscomposedofanANDgatecircuit,amonostabledelaycircuit,afour-wayinfraredtransmittingandreceivingcircuit,atriggerandatwo-colorlight-emittingcircuit,andanaudioalarmcircuit.FourpairsofwarninglinesfortransmissionandreceptioniscomposedofHF1~HF4(infraredlight-emittingdiodes)andBG1~BG4(infraredreceivingpairingtubes).Ifsomeonecrossesthewarninglineandtheinfraredbeamisblocked,thecorrespondingmatchingtubewillbecutoff.AndtheinputofthecorrespondingNANDgateishighlevel.Itmakesthetriggerterminalpin2ofIC3(555)obtainanegativedifferentialpulse,thatis,theoutputterminaloftheANDgatecomposedofD1~D4.Therefore,the555isset,andthehighlevelisoutputfrompin3whichmakesBG5saturatedandturnedon.ThechipIC4(KD-9562)ispoweredonandanalarmsoundisgiven.ThedelaywidthofIC3monostablecircuittd=1.1Rw1R3determinesthesoundtime.Thedelayalarmtimecorrespondingtotheparametersinthefigureisabout100seconds.Atthesametime,thecorrespondingtimecanbechangedbychangingthevalueofWandCaccordingtothespecificsituation.ThevoltagestabilizingtubeDWadopts2cw7or2cw10,andthevoltagerangeisabout3VtoprotectthemusicintegrationKD-9562,soastopreventitfromburningduetoover-voltage(highvoltage).ThechipKD-9562isaneightanalogsoundintegratedcircuit,whichcanselectthecorrespondingmusicaccordingtotheusesituationandpurpose.LM386isasinglepoweraudiopoweramplifierintegratedcircuit,whichisusedtoexpandtherangeofalarmsound.F1-1~F1-6,F2-1~F2-6usesixinverterCD4069.Two-colorlight-emittingdiodesLED1~LED4adopt2EF303.Undernormalconditions,theyemitgreenlight,andwhensomeonecrossesthewarningline,theysendoutredwarninglight.2.2CircuitofAutomobileVoiceHornFigure4.CircuitofAutomobileVoiceHornTheleftsideofthedottedlineinFigure4istheoriginalcircuitdiagramofthevehicleelectrichorn.SListheelectrichornbuttonswitchonthesteeringwheel.S2isanewlyaddedSPDTSwitch,whichisusedforswitchingbetweenelectrichornandvoicehornoftheoriginalvehicle.WhentheswitchS2issetto2,presstheswitchSl,thecapacitorClischarged,thetransistorsVTl,VT2turnon,therelayJlpullsin.J1-1isclosedandheldfor15secondstosupplypowertothecircuit.IClisadedicatedvoiceintegratedcircuitHL-169A.Sinceitsworkingtimeis2.8seconds,theself-excitedmultivibratoriscomposedoftransistorsVT3andVT4.Every3seconds,ahighlevelisoutputasatriggersignal,sothatICloutputsavoicesignalevery3seconds,andsendsittoIC2foraudiopoweramplification,andthespeakerBLemitsvoice.2.3CircuitofMicrocomputerStereoPowerAmplifierBecausetheaudiosignalamplitudeofthelineoutputofthesoundcardistoolarge,theLM386canbedriventopushthespeaker.Inaddition,duetotheinterferenceofvideosignalwhenplayingVCD,itisnotgoodtoconnecttheVCDaccordingtothetypicalcircuit,soitisnecessarytoaddsomecomponentsanddebugthecomponentvalues.TheschematicdiagramisshowninFigure5.Figure5.CircuitofMicrocomputerStereoPowerAmplifierLM386hastwoinputterminals,3pinin-phaseinputand2pininvertinginput.Theinputsignalcanbeinputfromanyendandtheotherinputterminalcanbegrounded.TheinputendisconnectedwithcapacitorC4inordertofilteroutthevideointerferencewhenplayingVCD.Thevaluecanbeincreasedappropriately,butitcanbeusedwithorwithoutC4whenplayingCD.Thepin1andpin8aregaincontrolterminals,whicharecomposedofC2andW2.Thesmallertheresistance,thehigherthegain.ItismoreappropriatetoadjustthegainofW2toabout150.Ifthegainistoohigh,itwilleasilycauseself-excitation.Pin7isconnectedtoa10capacitor.ThehighfrequencycomponentattenuationcircuitiscomposedofR2andC6toeliminatethecrashsoundfromtheloudspeaker.ThecapacityofC6canbeadjustedaccordingtotheactualeffect.Pin6isconnectedtothegroundwitha0.1capacitor,whichactsasafiltertoeliminatethestatichumoftheamplifier.Pin5isconnectedtothecouplingcapacitorC3.Ifonlyoneconespeakerisconnectedtoonechannel,C3capacityshouldnotexceed470,otherwisetheloudspeakerwillbeblockedwhenplayinglowmusic.Ifhigh-frequencyandlow-frequencycrossovertechnologyisadopted,thecapacityofC3canbeincreasedtomakethebassfullyreflected.W1isusedtoadjusttheoutputvolume,whichisparticularlyconvenientwhenplayinggamesorlisteningtoCDs.FAQHowdoesanLM386work?TheLm386integratedchipisalowpoweraudiofrequencyamplifier,whichuseslowlevelpowersupplylikebatteriesinelectroniccircuits.Itisdesignedas8pinminiDIPpackage.Thisprovidesvoltageamplificationof20.Byusingexternalpartsvoltagegaincanberaisedupto200.Islm386anopamp?TheLM386isatypeofoperationalamplifier(Op-Amp)....Inanamplifiercircuit,theLM386takesanaudioinputsignalandincreasesitspotentialanywherefrom20to200times.Thatamplificationiswhatsknownasthevoltagegain.Whatislm386IC?TheLM386isanintegratedcircuitcontainingalowvoltageaudiopoweramplifier.Itissuitableforbattery-powereddevicessuchasradios,guitaramplifiers,andhobbyelectronicsprojects.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhichICisusedinaudioamplifier?TheICLM386isalow-poweraudioamplifier,anditutilizeslowpowersupplylikebatteriesinelectricalandelectroniccircuits.ThisICisavailableinthepackageofmini8-pinDIP.WhataresomeprojectsthatusetheLM386audioamplifiercircuit?LM386isanintegratedclassABampandisgoodforbeginnerssmallaudioamplifierapplicationsforexampleinaRFreceiver,smallStereosystem,cheaplowvoltageamplifieretcdrawbacksisthatitcannothandlemuchpowerandhencecreatesdistortionwhenyoucrankupthevolumetoomuch..SootherICsareusedinpractical.HowtomakeanLM386audioamplifiercircuit?IntroductonLM386isalowvoltageaudiopoweramplifier.LM386adopts8-pindoublein-lineplasticpackagewithworkingvoltageof4V-15V.Whenthepowersupplyvoltageis12V,300mWoutputpowercanbeobtainedonan8load.VariousoscillatorscanbeeasilyproducedwithLM386.CatalogIntroductonCatalogISimplestOscillatorIIBlockingOscillatorIIIElectronicPianoIVSquare-waveOscillatorVSinusoidalOscillatorFAQOrdering&QuantityISimplestOscillatorFigure1.CircuitofSimplestOscillatorInFigure1,theoutputendandin-phaseinputendofLM386areconnectedbypiezoelectricceramicchipHTD.Theamplifierformspositivefeedbackandgeneratesoscillation.HereHTDisbothafeedbackcapacitorandasound-generatingdevice.Componentparametersinthefigure:D1~D4are1N4001,C1=220pF,HTDispiezoelectricceramicsheetwithauxiliaryacousticcavity.IIBlockingOscillatorFigure2.CircuitofBlockingOscillatorAsshowninFigure2,asimpleoscillatorconsisitofLM386,C3,C4andloudspeakers.RPandC2makethisoscillatorproduceblocking-oscillation.Afterconnectingthepowersupply,LM386doesnotworkbecausetheinitialterminalvoltageofC2iszero,andthepowersupplychargesC2throughRP.WhenC2chargingvoltageishigherthanacertainvalue,LM386oscillatorstartstovibrate.Astheamplitudecontinuestoincrease,thecurrentconsumptionoftheoscillatoralsoincreases.ThiscurrentflowsthroughRP,anditsvoltagedroponRPalsoincreases,causingtheLM386powersupplyterminal6pinvoltagetocontinuetodrop.EventuallytheLM386cannotworkandtheoscillatorstops.ThepowersupplyrechargesC2viaRPagain,causingthevoltageatC2torise.WhenthevoltageatC2risestoacertainvalue,theLM386oscillatorstartsagain.Inthisway,theoscillatorwillproduceblocking-oscillation,andthespeakeremitsbeep,beep,beepsound.Componentparametersinthefigure:D1~D4are1N4001,C1=C3=220F,piezoelectric pressure sensorsC2=47F.C4=0.01F,RP=4.7K.IIIElectronicPianoFigure3.CircuitofElectronicPianoFigure3isasimpleelectronicpianocircuit.Onthepin3ofLM386,theintegratedcircuithasa10Kresistortoground.Thisbuilt-inresistorandtenscaleresistorsRP1~RP10constitutethetimingresistoroftheoscillator.C2isthetimingcapacitor.ByadjustingthevaluesofRP1~RP10,thespeakerscansequentiallyemitmusicalsoundsfromlowoctavedo,re,mitohighoctavedo,re,mi.KI~K10arekeyswitches.Componentparametersinthefigure:Cl=C3=220F.C2=2200FIVSquare-waveOscillatorFigure4.CircuitofSquare-waveOscillatorFigure4showsasquare-waveoscillatorcomposedofLM386.R1isthetimingresistor.C2isthetimingcapacitor.R2andR3providevoltagebiasforLM386in-phaseinput.BecausethevoltageattheC2terminalcannotchangeabruptly,theinvertinginputterminalpin2oftheLM386islowlevel,andpin5isthemidpointoftheinternalOTLoutputstageoftheamplifier.Itis1/2Vocinstaticstate,anditissuppliedtothethird-phaseinputpin3afterdividingpressureviaR2andR3.Obviouslythepotentialofthispinishigherthanthesecondpin.Therefore,pin5outputshighlevel.ThishighlevelchargesC2viaR1.WhenthevoltageofC2terminalishigherthanthepotentialofpin3,pin5outputslowlevel.C2dischargestopin5viaR1.WhenC2isdischarged,thepotentialofpin2dropsandislowerthanthepotentialofpin3.Pin5outputshighlevelagain.Inthisway,thecircuitformsoscillation,andtheoscillationsignaldrivestheloudspeakertosoundthroughC3.Componentparametersinthefigure:C1=C3=220F,variable resistor symbolsC2=0.33F.R1=22K,R2=1K.R3=9.4KVSinusoidalOscillatorFigure5.CircuitofSinusoidalOscillatorFigure5isasinusoidaloscillatormadeofLM386.ThecircuitadoptsWienbridgeoscillationmode,andtheoutputsignaldistortioncoefficientofthecircuitisverylow.TheflashlampHandtheresistorR3formanegativefeedbackcircuit,whichkeepstheamplitudeoftheoscillatoroutputsignalstableandhaslowdistortion.WhenthevaluesofcapacitorsC1andC2arethesame,theoscillationfrequencyofthecircuitcanbeobtainedbytheformulaf=1/2C1R1R2.Inactualproduction,Hcanuse3V,15mAflashlamp.FAQHowdoesanLM386work?TheLm386integratedchipisalowpoweraudiofrequencyamplifier,whichuseslowlevelpowersupplylikebatteriesinelectroniccircuits.Itisdesignedas8pinminiDIPpackage.Thisprovidesvoltageamplificationof20.Byusingexternalpartsvoltagegaincanberaisedupto200.Islm386anopamp?TheLM386isatypeofoperationalamplifier(Op-Amp)....Inanamplifiercircuit,theLM386takesanaudioinputsignalandincreasesitspotentialanywherefrom20to200times.Thatamplificationiswhatsknownasthevoltagegain.Whatislm386IC?TheLM386isanintegratedcircuitcontainingalowvoltageaudiopoweramplifier.Itissuitableforbattery-powereddevicessuchasradios,guitaramplifiers,andhobbyelectronicsprojects.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhichICisusedinaudioamplifier?TheICLM386isalow-poweraudioamplifier,anditutilizeslowpowersupplylikebatteriesinelectricalandelectroniccircuits.ThisICisavailableinthepackageofmini8-pinDIP.WhataresomeprojectsthatusetheLM386audioamplifiercircuit?LM386isanintegratedclassABampandisgoodforbeginnerssmallaudioamplifierapplicationsforexampleinaRFreceiver,smallStereosystem,cheaplowvoltageamplifieretcdrawbacksisthatitcannothandlemuchpowerandhencecreatesdistortionwhenyoucrankupthevolumetoomuch..SootherICsareusedinpractical.HowtomakeanLM386audioamplifiercircuit?

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