LM1875T中文资料

LM187520WAudioPowerAmplifierGeneralDescriptionTheLM1875isamonolithicpoweramplifierofferingverylowdistortionandhighqualityperformanceforconsumeraudioapplications.TheLM1875delivers20wattsintoa4Ωor8Ωloadon±25Vsupplies.Usingan8Ωloadand±30Vsupplies,over30wattsofpowermaybedelivered.Theamplifierisdesignedtooperatewithaminimumofexternalcomponents.Deviceoverloadprotectionconsistsofbothinternalcurrentlimitandthermalshutdown.TheLM1875designtakesadvantageofadvancedcircuittechniquesandprocessingtoachieveextremelylowdistor-tionlevelsevenathighoutputpowerlevels.Otheroutstand-ingfeaturesincludehighgain,fastslewrateandawidepowerbandwidth,largeoutputvoltageswing,highcurrentcapability,andaverywidesupplyrange.Theamplifierisin-ternallycompensatedandstableforgainsof10orgreater.FeaturesnUpto30wattsoutputpowernAVOtypically90dBnLowdistortion:0.015%,1kHz,20WnWidepowerbandwidth:70kHznProtectionforACandDCshortcircuitstogroundnThermalprotectionwithparolecircuitnHighcurrentcapability:4AnWidesupplyrange16V-60VnInternaloutputprotectiondiodesn94dBripplerejectionnPlasticpowerpackageTO-220ApplicationsnHighperformanceaudiosystemsnBridgeamplifiersnStereophonographsnServoamplifiersnInstrumentsystemsConnectionDiagramPackageOrderingInfoNSCPackageNumberForStraightLeadsLM1875TSL108949T05AForStaggerBendLM1875TLB03T05DFor90˚StaggerBendLM1875TLB05T05EFor90˚StaggerBendLM1875TLB02TA05BTypicalApplicationsDS005030-1FrontViewDS005030-2February1999LM187520WAudioPowerAmplifier©1999NationalSemiconductorCorporationDS005030(Note1)SupplyVoltage60VInputVoltage−VEEtoVCCStorageTemperature−65˚Cto+150˚CJunctionTemperature150˚CLeadTemperature(Soldering,10seconds)260˚CθJC3˚CθJA73˚CElectricalCharacteristicsVCC=+25V,−VEE=−25V,TAMBIENT=25˚C,RL=8Ω,AV=20(26dB),fo=1kHz,unlessotherwisespecified.ParameterConditionsTypicalTestedLimitsUnitsSupplyCurrentPOUT=0W70100mAOutputPower(Note2)THD=1%25WTHD(Note2)POUT=20W,fo=1kHz0.015%POUT=20W,fo=20kHz0.050.4%POUT=20W,RL=4Ω,fo=1kHz0.022%POUT=20W,RL=4Ω,fo=20kHz0.070.6%OffsetVoltage±1±15mVInputBiasCurrent±0.2±2μAInputOffsetCurrent0±0.5μAGain-BandwidthProductfo=20kHz5.5MHzOpenLoopGainDC90dBPSRRVCC,1kHz,1Vrms9552dBVEE,1kHz,1Vrms8352dBMaxSlewRate20W,8Ω,70kHzBW8V/μsCurrentLimitVOUT=VSUPPLY−10V43AEquivalentInputNoiseVoltageRS=600Ω,CCIR3μVrmsNote1:“AbsoluteMaximumRatings”indicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsforwhichthedeviceisfunctional,butdonotguaranteespecificperformancelimits.Note2:Assumestheuseofaheatsinkhavingathermalresistanceof1˚C/Wandnoinsulatorwithanambienttemperatureof25˚C.Becausetheoutputlimitingcircuitryhasanegativetemperaturecoefficient,themaximumoutputpowerdeliveredtoa4Ωloadmaybeslightlyreducedwhenthetabtemperatureexceeds55˚C.TypicalApplicationsTypicalSingleSupplyOperationDS005030-3†DS005030-14†ϕINTERFACE=1˚C/W.SeeApplicationHints.PowerDissipationvsPowerOutputDS005030-15PowerDissipationvsPowerOutputDS005030-16IOUTvsVOUT-CurrentLimit/SafeOperatingAreaBoundaryDS005030-17(Continued)OpenLoopGainandPhasevsFrequencyDS005030-18Note3:ThermalshutdownwithinfiniteheatsinkNote4:Thermalshutdownwith1˚C/WheatsinkInputBiasCurrentvsSupplyVoltageDS005030-19(feedbackandinput)groundstothecircuitboardgroundpointthroughseparatepaths.Otherwise,largecurrentsflowingalongagroundconductorwillgeneratevoltagesontheconductorwhichcaneffectivelyactassignalsattheinput,resultinginhighfrequencyoscillationorexcessivedistortion.Itisadvis-abletokeeptheoutputcompensationcomponentsandthe0.1μFsupplydecouplingcapacitorsascloseaspossibletotheLM1875toreducetheeffectsofPCBtraceresistanceandinductance.Forthesamereason,thegroundreturnpathsforthesecomponentsshouldbeasshortaspossible.Occasionally,currentintheoutputleads(whichfunctionasantennas)canbecoupledthroughtheairtotheamplifierin-put,resultinginhigh-frequencyoscillation.Thisnormallyhappenswhenthesourceimpedanceishighortheinputleadsarelong.Theproblemcanbeeliminatedbyplacingasmallcapacitor(ontheorderof50pFto500pF)acrossthecircuitinput.Mostpoweramplifiersdonotdrivehighlycapacitiveloadswell,andtheLM1875isnoexcept