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3.0A,150Khz,Step-DownSwitchingRegulatorFEATURES3.3V,5.0V,12V,15V,andAdjustableOutputVersionsAdjustableVersionOutputVoltageRange,1.23to37V+/-4%.MaximumOverLineandLoadConditionsGuaranteed3.0AOutputCurrentWideInputVoltageRangeRequiresOnly4ExternalComponents150KhzFixedFrequencyInternalOscillatorTTLShutdownCapability,LowPowerStandbyModeHighEfficiencyUsesReadilyAvailableStandardInductorsThermalShutdownandCurrentLimitProtectionMoistureSensitivityLevel(MSL)Equals1ApplicationsSimpleHigh-EfficiencyStep-Down(Buck)RegulatorEfficientPre-RegulatorforLinearRegulatorsOn-CardSwitchingRegulatorsPositivetoNegativeConverter(Buck-Boost)NegativeStep-UpConvertersPowerSupplyforBatteryChargersDESCRIPTIONORDERINGINFORMATIONTheLM2596seriesofregulatorsaremonolithicintegratedcircuitsideallysuitedforeasyandconvenientdesignofastep-downswitchingregualtor(buckconverter).Allcircuitsofthisseriesarecapableofdrivinga3.0Aloadwithexcellentlineandloadregulation.Thesedevicesareavailableinfixedoutputvoltagesof3.3V,5.0V,12V,15V,andanadjustableoutputversion.Theseregulatiorsweredesignedtominimizethenumberofexternalcomponentstosimplifythepowersupplydesign.StandardseriesofinductorsoptimizedforusewiththeLM2576areofferedbyseveraldifferentinductormanufacturers.SincetheLM2596converterisaswitch-modepowersupply,itsefficiencyissignificantlyhigherincomparisonwithpopularthree-terminallimearreguators,especiallywithhigherinputvoltages.availablefromseveraldifferentmanufacturers.Thisfeaturegreatlysimplifiesthedesignofswitch-modepowersupplies.TheLM2596featuresincludeaguaranteed+/-4%toleranceonoutputvoltagewithinspecifiedinputvoltagesandoutputloadconditions,and+/-15%ontheoscillatorfrequency(+/-2%over0oCto125oC).Externalshutdownisincluded,featuring80uA(typical)standbycurrent.Theoutputswitchincludescycle-bycyclecurrentlimiting,aswellasthermalshutdownforfullprotectionunderfaultconditions.TO-220VHTC1LM2596Inmanycases,thepowerdissipatedissolowthatnoheatsinkisrequiredoritssizecouldbereduceddramatically.AstandardseriesofinductorsoptimizedforusewiththeLM2596areLM2596TV-X.XLM2596T-X.XDeviceMarkingPackageLM2596T-X.XLM2596T-X.XTO-220LM2596RLM2596R-X.XTO-263TO-220VTO-2201.Vin2.Output3.Ground4.Feedback5.On/OffTO-263(D2)Oct2004-Rev03.0A,15V,Step-DownSwitchingRegulatorHTC2LM2596Figure1.BlockDiagramandTypicalApplicationABSOLUTEMAXIMUMRATINGS(AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccur.)TO-220,5-LeadTO-263ThermalResistance,Junction-to-AmbientThermalResistance,Junction-to-caseThermalResistance,Junction-to-AmbientThermalResistance,Junction-to-casePowerDissipationTypicalApplication(FixedOutputVoltageVersions)680uF220uF1N582433uHLM2596-5.0Oct2004-Rev03.0A,15V,Step-DownSwitchingRegulatorHTC3LM2596OPERATINGRATINGS(OperatingRatingsindicateconditionsforwhichthedeviceisintendedtobefunctional,butdonotguaranteespecificperformancelimits.Forguaranteedspecificationsandtestconditions,seetheElectricalCharacteristics.)ELECTRICALCHARACTERISTICS/SYSTEMPARAMETERS([Note1]TestCircuitFigure2)(Unlessotherwisespecified,Vin=12Vforthe3.3V,5.0V,andAdjustableversion,Vin=25Vforthe12Vversion,andVin=30Vforthe15Vversion.ILoad=500mA.FortypicalvaluesTJ=25°C,formin/maxvaluesTJistheoperatingjunctiontemperaturerangethatapplies[Note2],unlessotherwisenoted.)73809098LM2596-3.3([Note1].TestCircuitFigure2)73LM2596-5.0([Note1].TestCircuitFigure1)LM2596-ADJ([Note1].TestCircuitFigure2)LM2596-15([Note1].TestCircuitFigure2)LM2596-12([Note1].TestCircuitFigure2)LM2596-5.0([Note1].TestCircuitFigure2)Oct2004-Rev03.0A,15V,Step-DownSwitchingRegulatorLM2596HTC4ELECTRICALCHARACTERISTICS/DeviceParameters(Unlessotherwisespecified,Vin=12Vforthe3.3V,5.0V,andAdjustableversion,Vin=25Vforthe12Vversion,andVin=30Vforthe15Vversion.ILoad=500mA.FortypicalvaluesTj=25°C,formin/maxvaluesTjistheoperatingjunctiontemperaturerangethatapplies[Note2],unlessotherwisenoted.)1.Externalcomponentssuchasthecatchdiode,inductor,inputandoutputcapacitorscanaffectswitchingregulatorsystemperformance.WhentheLM2596isusedasshownintheFigure1testcircuit,systemperformancewillbeasshowninsystemparameterssection.2.TestedjunctiontemperaturerangefortheLM2596:TLOW=–0°CTHIGH=+125°C3.Theoscillatorfrequencyreducestoapproximately18kHzintheeventofanoutputshortoranoverloadwhichcausestheregulatedoutputvoltagetodropapproximately40%fromthenominaloutputvoltage.ThisselfprotectionfeaturelowerstheaveragedissipationoftheICbyloweringtheminimumdutycyclefrom5%downtoapproximately2%.4.Output(Pin2)sourcingcurrent.Nodiode,inductororcapacitorconnectedtooutputpin.5.Feedback(Pin4)removedfromoutputandconnectedto0V.6.Feedback(Pin4)removedfromoutputandconnectedto+12VfortheAdjustable,3.3V,and5.0Versions,and+25Vforthe12Vand15Vversions,toforcetheoutputtransistor“off”.7.Vin=40V.22105001501731001271101.161.54.53.6100173-1.40000003.46.97.5-50230-1052500.6-2.0-1.30.61.3-5152.00.025.0VLOGIC=2.5V(RegulatorOFF)VLOGIC=0.5V(RegulatorON)Oct2004-Rev03.0A,15V,Step-DownSwitchingRegulatorLM2596HTC5TYPICALPERFORMANCECHARACTERISTICS(CircuitofFigure2)Oct2004-Rev03.0A,15V,Step-DownSwitchingRegulator6LM