SD6271恒流模式的PWM升压IC,内置过温、关断、欠压、过流保护

SD6271TheSD6271isavailableintheSOT23-6LpaTheSD6271isacurrentmodeboostDC-DCconvSD62711MHz,2AStep-UpCurrentModePWMConverter1/9GeneralDescriptionerter.ItsPWMcircuitrywithbuilt-in0.25ΩpowerMOSFETmakethisregulatorhighlypowerefficient.Theinternalcompensationnetworkalsominimizesasmuchas6externalcomponentcounts.Thenon-invertinginputoferroramplifierconnectstoa0.6Vprecisionreferencevoltageandinternalsoft-startfunctioncanreducetheinrushcurrent.ckageandprovidesspace-savingPCBfortheapplicationfields.FeaturesAdjustableOutputupto24VInternalFixedPWMfrequency:1.0MHzPrecisionFeedbackReferenceVoltage:0.6V(±2%)Internal0.25Ω,2A,26VPowerMOSFETShutdownCurrent:0.1μAOverVoltageProtectionOverTemperatureProtectionAdjustableOverCurrentProtection:0.5A~2.5APackage:SOT23-6LApplicationsChargersLCDDisplaysDigitalCamerasHandheldDevicesPortableProductsTypicalApplicationCircuitSHOUDINGAL*AL***2/9FunctionBlockDiagramPinDescriptionsSOT23-6L123654OCENLXGNDFBAL**TopViewNameNo.I/ODescriptionLX1OPowerSwitchOutputGND2PICGroundFB3IErrorAmplifierInvertingInputEN4IEnableControl(ActiveHigh)VCC5PICPowerSupplyOC6IAdjustableCurrentLimit(FloatingAvailable)******SD6271SHOUDINGyearAL***3/9MarkingInformationSOT23-6LLotNumberPartNumberCodeAL***LotNumber:Waferlotnumber’slasttwodigitsForExample:132386TB86Year:Productionyear’slastdigitPartNumberCode:Partnumberidentificationcodeforthisproduct.Itshouldbealways“AL”.**SD6271SHOUDINGSD6271LR-G1AL4/9OrderingInformationPartNumberCodeOperatingTemperaturePackageMOQDescription-40°C~85°CSOT23-6L3000EATape&ReelAbsoluteMaximumRatingsParameterSymbolConditionsMin.Typ.Max.UnitSupplyVoltageVCC06VOVPVoltageVOVP028VLXVoltageVLX028VEN,FBVoltage06VPowerDissipationPDSOT23-6L@TA=25°C455mWThermalResistance(Note1)θJASOT23-6L+220°C/WJunctionTemperatureTJ+150°COperatingTemperatureTOP-40+85°CStorageTemperatureTST-65+150°CLeadTemperature(soldering,10sec)+260°CNote1:θJAismeasuredinthenaturalconvectionatTA=25°ConaloweffectivethermalconductivitytestboardofJEDEC51-3thermalmeasurementstandard.IRRe-flowSolderingCurveSD6271SHOUDING5/9RecommendedOperatingConditionsParameterSymbolConditionsMin.Typ.Max.UnitSupplyVoltageVIN2.65.5VOperatingTemperatureRangeTAAmbientTemperature-40+85°CDCElectricalCharacteristics(VCC=3.3V,TA=25°C,unlessotherwisespecified)ParameterSymbolConditionsMin.Typ.Max.UnitSystemSupplyInputInputSupplyRangeVCC2.65.5VUnderVoltageLockoutVUVLO2.2VUVLOHysteresis0.1VQuiescentCurrentICCVFB=0.66V,Noswitching0.16mAAverageSupplyCurrentICCVFB=0.55V,Switching2.84mAShutdownSupplyCurrentICCVEN=GND0.1µAOscillatorOperationFrequencyFOSCVFB=1.0V0.81.01.2MHZFrequencyChangewithVoltagef△/V△VCC=2.7Vto5.5V5%MaximumDutyCycleTDUTY90%ReferenceVoltageFeedbackVoltageVREF0.5880.60.612VLineRegulationVCC=2.7V～5.5V0.05%/VEnableControlEnableVoltageVEN0.96VShutdownVoltageVEN0.6VMOSFETOnResistanceofDriverRDS(ON)ILX=2A0.25ΩProtectionOVPThresholdVoltageVOVP27VOVPSinkCurrentISINK5µAOCPCurrentIOCP22.6AAdjustableOCPCurrentIOCPWithExternalResistor：10k~100k0.52.6AOTPTemperatureTOTP+150°CSD6271SHOUDINGlevel.TheSD6271’sOVPthresholdis27V.high.TheSD6271startupandoperates.TheSD6271willturnoffthepowerMOSFETautomaticallySoftstartcircuitryisintegratedintoSD6271toavTheSD6271isacurrentmodeboostconverter.6/9FunctionDescriptionOperationTheconstantswitchingfrequencyis1MHzandoperateswithpulsewidthmodulation(PWM).Build-in26V/2AMOSFETprovidesahighoutputvoltage.Thecontrollooparchitectureispeakcurrentmodecontrol;thereforeslopecompensationcircuitisaddedtothecurrentsignaltoallowstableoperationfordutycycleslargerthan50%.SoftStartFunctionoidinrushcurrentduringpoweron.AftertheICisenabled,theoutputoferroramplifierisclampedbytheinternalsoft-startfunction,whichcausesPWMpulsewidthincreasingslowlyandthusreducinginputsurgecurrent.CurrentLimitProgramAresistorbetweenOCandGNDpinprogramspeakswitchcurrent.Theresistorvalueshouldbebetween10kand100k.Thecurrentlimitwillbesetfrom2.5Ato0.5A.Keeptracesatthispinasshortaspossible.Donotputcapacitanceatthispin.Tosettheovercurrenttrippointaccordingtothefollowingequation:3R48000IOCPOverVoltageProtection(OVP)Insomecondition,theresistivedividermaybeunconnected,whichwillcausePWMsignaltooperatewithmaximumdutycycleandpowerswitchvoltageisboostedhigherandhigher.ThepowerMOSFETwillbeturnedoffimmediately,whenthepowerswitchvoltageexceedstheOVPthresholdOverTemperatureProtection(OTP)whentheinternaljunctiontemperatureisover150°C.ThepowerMOSFETwakeupwhenthejunctiontemperaturedrops30°CundertheOTPthresholdtemperature.OutputDisconnectWhenpoweronandtheENpinwillbepulledexternalPMOSisturnedonandcurrentthroughitforoutputloading.Whileoutputloadingisincrease,outputvoltageisdrop.WhentheFBpinvoltageisunder0.3V,theENpinsinks20µAcurrent,theexternalPMOSwillbeturnoff.Theoutputshortconditionwillbedisconnected.SD6271SHOUDING7/9ApplicationInformationInductorSelectionInductancevalueisdecidedbasedondifferentcondition.4.7to22µHinductorvalueisrecommendedforgeneralapplicationcircuit.Therearethreeimportantinductorspecifications,DCresistance,saturationcurrentandcoreloss.LowDCresistancehasbetterpo