AX3513-V1.2

1/13AxeliteConfidentialMaterials,donotcopyordistributewithoutwrittenconsent.Rev.1.2Jan.13,2010AX35131.4MHz,1ASynchronousStep-DownConverter™GENERALDESCRIPTIONAX3513isahighefficiencymonolithicsynchronousbuckregulatorusingaconstantfrequency,currentmodearchitecture.Thedeviceisavailableinanadjustableversion.Supplycurrentwithnoloadis250uAanddropsto1uAinshutdown.The2.5Vto6VinputvoltagerangemakesAX3513ideallysuitedforsingleLi-Ion,twotofourAAbattery-poweredapplications.100%dutycycleprovideslowdropoutoperation,extendingbatterylifeinportablesystems.PWMpulseskippingmodeoperationprovidesverylowoutputripplevoltagefornoisesensitiveapplications.Switchingfrequencyisinternallysetat1.4MHz,allowingtheuseofsmallsurfacemountinductorsandcapacitors.Theinternalsynchronousswitchincreasesefficiencyanddecreasesneedofanexternalschottkydiode.Lowoutputvoltagesareeasilysupportedwiththe0.6Vfeedbackreferencevoltage.AX3513isavailableinsmallTSOT23-5LandDFN-6Lpackages.™FEATURES-2.5Vto6VInputVoltageRange-OutputVoltagefrom0.6VtoVIN-HighEfficiency:Upto96%-1.4MHzConstantFrequencyOperation-Upto1AOutputCurrent-QuiescentCurrent:250uA(Typical)-NoSchottkyDiodeRequired-CurrentModeOperationforExcellentLineandLoadTransientResponse-Currentlimit,Enablefunction-ShortCircuitProtect(SCP)-Buildinsoftstartfunction-≤1µAShutdownCurrent-TSOT23-5LandDFN-6LPb-Freepackages0755-8398337713590112223™BLOCKDIAGRAMFBENVINSWGNDOver-TemperatureandShort-CircuitProtectionREFSoft-Star0.6V+--+Icomp-+IsenseAMPOSCSLOPECOMPPWMLOGIC-+IzeroCOMPNON-OVERLAPCONTROLRESETSETEnableLogic™PINASSIGNMENTThepackagesofAX3513areTSOT23-5LandDFN-6L;thepinassignmentisgivenby:(TopView)ENGNDSWVINFB12345TSOT23-5LDFN-6L(2*2)VINFBSW123456ENGNDNCGNDNameDescriptionENEnablepinH：normaloperationL：ShutdownVINPowerSupplyInputPinSWSwitchoutputpin.Connectexternalinductorhere.MinimizetraceareaatthispintoreduceEMI.GNDGroundPinFBOutputFeedbackpinNCNoConnect.0755-8398337713590112223™ORDER/MARKINGINFORMATIONOrderInformationPackageTypeAX3513PackingA:TapingXXXBT:TSOT23-5LZ2:DFN-6L(2*2)TopMarking(TSOT23-5L)TopMarking(DFN-6L)GXXXXPackageWW:01~26(A~Z27~52(a~z)Year:7=2007A=2010IDcode:internal)G6:TSOT23-5LG7YWXYear:9=2009A=2010AX3513Week:01~26(A~Z)27~52(a~z)IDCode:Internal™ABSOLUTEMAXIMUMRATINGS(atTA=25°C)CharacteristicsSymbolRatingUnitVINPinVoltageVINVSS-0.3toVSS+6.5VFeedbackPinVoltageVFBVSS-0.3toVIN+0.3VENPinVoltageVENVSS-0.3toVIN+0.3VSwitchPinVoltageVSWVSS-0.3toVIN+0.3VPeakSWSinkandSourceCurrentIPSW1.4APowerDissipationPD(TJ-TA)/θJAmWStorageTemperatureRangeTST-40to+150°COperatingTemperatureRangeTOP-40to+85°CJunctionTemperatureTJ+125°CDFN-6L25ThermalResistancefromJunctiontocaseTSOT23θJC110°C/WDFN-6L120ThermalResistancefromJunctiontoambientTSOT23θJA250°C/WNote:θJAismeasuredwiththePCBcopperareaofapproximately1in2(Multi-layer).ThatneedconnecttoGNDpinorexposedpad(AX3513Z2).0755-8398337713590112223™ELECTRICALCHARACTERISTICS(VIN=VEN=3.6V,TA=25°C,unlessotherwisespecified)CharacteristicsSymbolConditionsMinTypMaxUnitsInputVoltageRangeVIN2.5-6VTA=+25°C0.5880.6000.612FeedbackVoltageVFB-40°C≤TA≤85°C0.5820.6000.618VFeedbackBiasCurrentIFBVFB=0.65V--±30nAQuiescentCurrentICCQVFB=1V-250350uAShutdownSupplyCurrentISDVEN=0V-0.11uASwitchingCurrentLimitILIMIT1.21.4-ALineRegulation△VOUT/VOUTVIN=2.5Vto5.5V-0.040.4%/VLoadRegulation△VOUT/VOUTIOUT=0.01to1A-0.5-%OscillationFrequencyFOSCSWpin1.11.41.7MHzRDS(ON)ofP-CHMOSFETRDSONVFB=0V,IOUT=0.5A-0.30.4ΩRDS(ON)ofN-CHMOSFETRDSON(Note1)-0.250.35ΩVENL--0.4ENpinlogicinputthresholdvoltageVENH1.5--VENPinInputCurrentIEN-±0.1±1uAEfficiencyEFFIVIN=5V,VOUT=3.3V,IOUT=0.5A-94-%ThermalshutdownTDS-140-°CThermalshutdownHysteresisTSH-30-°CNote1:Guaranteedbydesign.0755-8398337713590112223™APPLICATIONCIRCUITVOUT=0.6*(1+R1/R2)R2300KC14.7uC210uVOUT=1.8VR2=100K~330KL12.7uHR1600KU1AX3513VINENGNDSWFBC315pVIN=2.5V~6V™FUNCTIONDESCRIPTIONSOperationAX3513isamonolithicswitchingmodestep-downDC-DCconverter.ItutilizesinternalMOSFETstoachievehighefficiencyandcangenerateverylowoutputvoltagebyusinginternalreferenceat0.6V.Itoperatesatafixedswitchingfrequency,andusestheslopecompensatedcurrentmodearchitecture.Thisstep-downDC-DCConvertersuppliesminimum1000mAoutputcurrentatinputvoltagerangefrom2.5Vto5.5V.CurrentModePWMControlSlopecompensatedcurrentmodePWMcontrolprovidesstableswitchingandcycle-by-cyclecurrentlimitforexcellentloadandlinetransientresponsesandprotectionoftheinternalmainswitch(P-ChMOSFET)andsynchronousrectifier(N-CHMOSFET).Duringnormaloperation,theinternalP-ChMOSFETisturnedonforacertain