RT8293A

RT8293A1DS8293A-03March2011:`RoHScompliantandcompatiblewiththecurrentrequire-mentsofIPC/JEDECJ-STD-020.`SuitableforuseinSnPborPb-freesolderingprocesses.ApplicationszWirelessAP/RouterzSet-Top-BoxzIndustrialandCommercialLowPowerSystemszLCDMonitorsandTVszGreenElectronics/ApplianceszPointofLoadRegulationofHigh-PerformanceDSPs3A,23V,340kHzSynchronousStep-DownConverterGeneralDescriptionTheRT8293Aisahighefficiency,monolithicsynchronousstep-downDC/DCconverterthatcandeliverupto3Aoutputcurrentfroma4.5Vto23Vinputsupply.TheRT8293A'scurrentmodearchitectureandexternalcompensationallowthetransientresponsetobeoptimizedoverawiderangeofloadsandoutputcapacitors.Cycle-by-cyclecurrentlimitprovidesprotectionagainstshortedoutputsandsoft-starteliminatesinputcurrentsurgeduringstart-up.TheRT8293Aalsoprovidesoutputundervoltageprotectionandthermalshutdownprotection.Thelowcurrent(3μA)shutdownmodeprovidesoutputdisconnection,enablingeasypowermanagementinbattery-poweredsystems.TheRT8293AisavailableinanSOP-8(ExposedPad)package.Featureszzzzz±±±±±1.5%HighAccuracyFeedbackVoltagezzzzz4.5Vto23VInputVoltageRangezzzzz3AOutputCurrentzzzzzIntegratedN-MOSFETSwitcheszzzzzCurrentModeControlzzzzzFixedFrequencyOperation:340kHzzzzzzOutputAdjustablefrom0.8Vto20VzzzzzUpto95%EfficiencyzzzzzProgrammableSoft-StartzzzzzStablewithLow-ESRCeramicOutputCapacitorszzzzzCycle-by-CycleOverCurrentProtectionzzzzzInputUnderVoltageLockoutzzzzzOutputUnderVoltageProtectionzzzzzThermalShutdownProtectionzzzzzRoHSCompliantandHalogenFreePinConfigurations(TOPVIEW)SOP-8(ExposedPad)BOOTVINSWGNDSSENFBCOMPGND23456789MarkingInformationRT8293AxGSP:ProductNumberx:HorLYMDNN:DateCodeRT8293AxZSP:ProductNumberx:HorLYMDNN:DateCodeRT8293AxGSPYMDNNRT8293AxZSPYMDNNRT8293AxGSPRT8293AxZSPPackageTypeSP:SOP-8(ExposedPad-Option1)RT8293ALeadPlatingSystemG:Green(HalogenFreeandPbFree)Z:ECO(EcologicalElementwithHalogenFreeandPbfree)H:UVPHiccupL:UVPLatch-OffRT8293A2DS8293A-03March2011(ExposedPad)GNDGround.TheexposedpadmustbesolderedtoalargePCBandconnectedtoGNDformaximumpowerdissipation.5FBFeedbackInputpin.Thispinisconnectedtotheconverteroutput.Itisusedtosettheoutputoftheconvertertoregulatetothedesiredvalueviaaninternalresistivevoltagedivider.Foranadjustableoutput,anexternalresistivevoltagedividerisconnectedtothispin.6COMPCompensationNode.COMPisusedtocompensatetheregulationcontrolloop.ConnectaseriesRCnetworkfromCOMPtoGND.Insomecases,anadditionalcapacitorfromCOMPtoGNDisrequired.7ENEnableInputPin.Alogichighenablestheconverter;alogiclowforcestheRT8293Aintoshutdownmodereducingthesupplycurrenttolessthan3μA.AttachthispintoVINwitha100kΩpullupresistorforautomaticstartup.8SSSoft-StartControlInput.SScontrolsthesoft-startperiod.ConnectacapacitorfromSStoGNDtosetthesoft-startperiod.A0.1μFcapacitorsetsthesoft-startperiodto13.5ms.VOUT(V)R1(kW)R2(kW)RC(kW)CC(nF)L(mH)COUT(mF)8273333.32222x256211.8203.31522x23.37524133.31022x22.525.5129.13.36.822x21.510.5125.63.33.622x21.212244.33.33.622x213123.63.3222x2Table1.RecommendedComponentSelectionTypicalApplicationCircuitVINENGNDBOOTSW7231L10µH100nF22µFx2R175kR224kVOUT3.3V/3A10µFx2VIN4.5Vto23VRT8293ASS8CSS4,9(ExposedPad)CBOOTCIN0.1µFCOUTREN100kCOMPCC3.3nFRC13kCPOpen6FB5RT8293A3DS8293A-03March2011µASlopeCompCurrentComparator+-EA0.8VSRQQSS+-1.2VLockoutComparatorVCC+85mΩ85mΩRT8293A4DS8293A-03March2011(VIN=12V,TA=25°C,unlessotherwisespecified)AbsoluteMaximumRatings(Note1)lSupplyVoltage,VIN-----------------------------------------------------------------------------------------0.3Vto25VlInputVoltage,SW-------------------------------------------------------------------------------------------0.3Vto(VIN+0.3V)lVBOOT-VSW--------------------------------------------------------------------------------------------------0.3Vto6VlOtherPinsVoltage-------------------------------------------------------------------------------------------0.3Vto6VlPowerDissipation,PD@TA=25°CSOP-8(ExposedPad)-------------------------------------------------------------------------------------1.333WlPackageThermalResistance(Note2)SOP-8(ExposedPad),θJA--------------------------------------------------------------------------------75°C/WSOP-8(ΕxposedPad),θJC-------------------------------------------------------------------------------15°C/WlLeadTemperature(Soldering,10sec.)-----------------------------------------------------------------260°ClJunctionTemperature--------------------------------------------------------------------------------------150°ClStorageTemperatureRange----