MAX1945REUI+中文资料

GeneralDescriptionTheMAX1945R/MAX1945Shigh-efficiencypulse-widthmodulation(PWM)switchingregulatorsdeliverupto6Aofoutputcurrent.Thedevicesoperatefromaninputsupplyrangeof2.6Vto5.5Vandprovideselectableoutputvoltagesof1.8V,2.5V,andadjustableoutputvoltagesfrom0.8Vto85%ofthesupplyvoltage.WithVCCat3.3V/5V,theinputvoltagecanbeaslowas2.25V.TheMAX1945R/MAX1945Sareidealforon-boardpost-regulationapplications.Totaloutputvoltageerrorislessthan±1%overload,line,andtemperature.TheMAX1945R/MAX1945Soperateataselectablefixedfrequency(500kHzor1MHz)orcanbesynchro-nizedtoanexternalclock(400kHzto1.2MHz).Thehighoperatingfrequencyminimizesthesizeofexternalcomponents.Thehighbandwidthoftheinternalerroramplifierprovidesexcellenttransientresponse.TheMAX1945R/MAX1945ShaveinternaldualN-channelMOSFETstolowerheatdissipationatheavyloads.TwoMAX1945R/MAX1945Sscanoperate180degreesout-of-phaseofeachothertominimizeinputcapacitance.Thedevicesprovideoutputvoltagemarginingforboard-leveltesting.TheMAX1945Rprovidesa±4%voltagemargining.TheMAX1945Sprovidesa±9%voltagemargining.TheMAX1945R/MAX1945Sareavailablein28-pinTSSOP-EPpackagesandarespecifiedoverthe-40°Cto+85°Cindustrialtemperaturerange.Anevaluationkitisavailabletospeeddesigns.ApplicationsLow-Voltage,High-DensityDistributedPowerSuppliesASIC,CPU,andDSPCoreVoltagesRAMPowerSupplyBaseStation,Telecom,andNetworkingEquipmentPowerSuppliesServerandNotebookPowerSuppliesFeatures♦6APWMStep-DownRegulatorwith95%Efficiency♦1MHz/500kHzSwitchingforSmallExternalComponents♦0.76in2Complete6ARegulatorFootprint♦ExternalComponents’Height3mm♦±1%OutputAccuracyoverLoad,Line,andTemperature♦Operatefrom2.6Vto5.5VSupply♦Operatefrom2.5VInputwithVCCat3.3V/5V♦PresetOutputVoltageof1.8Vor2.5V♦AdjustableOutputfrom0.8Vto85%ofInput♦VoltageMargining:±4%(MAX1945R)or±9%(MAX1945S)♦SynchronizetoExternalClock♦SYNCOUTProvides180-DegreeOut-of-PhaseClockOutput♦All-CeramicorElectrolyticCapacitorDesignsMAX1945R/MAX1945S1MHz,1%Accurate,6AInternalSwitchStep-DownRegulators________________________________________________________________MaximIntegratedProducts1OrderingInformationINFBREFCOMPLXBSTGNDVCCPGNDINPUT2.6VTO5.5VFBSELCTL1CTL2SYNCSYNCOUTOUTPUT0.8VTO0.85xVIN,6AVOLTAGEMARGININGON/OFFSYNCHRONIZATIONCLOCKVDDMAX1945RMAX1945S180°OUT-OF-PHASETypicalOperatingCircuit19-2640;Rev1;7/04Forpricing,delivery,andorderinginformation,pleasecontactMaxim/DallasDirect!at1-888-629-4642,orvisitMaxim’swebsiteat*EP=Exposedpad.PinConfigurationappearsatendofdatasheet.EVALUATIONKITAVAILABLEPARTTEMPRANGEPIN-PACKAGEMAX1945REUI-40°Cto+85°C28TSSOP-EP*MAX1945SEUI-40°Cto+85°C28TSSOP-EP*MAX1945R/MAX1945S1MHz,1%Accurate,6AInternalSwitchStep-DownRegulators2_______________________________________________________________________________________ABSOLUTEMAXIMUMRATINGSELECTRICALCHARACTERISTICS(VIN=VCC=VCTL1=VCTL2=VDD=3.3V,SYNC=GND,FBSEL=High-Z,VFB=0.7V,CREF=0.22µF,TA=0°Cto+85°C,unlessotherwisenoted.Typicalvaluesareat+25°C.)Stressesbeyondthoselistedunder“AbsoluteMaximumRatings”maycausepermanentdamagetothedevice.Thesearestressratingsonly,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedintheoperationalsectionsofthespecificationsisnotimplied.Exposuretoabsolutemaximumratingconditionsforextendedperiodsmayaffectdevicereliability.CTL1,CTL2,IN,SYNC,VCC,VDDtoGND...............-0.3Vto+6VSYNCOUT,COMP,FB,FBSEL,REFtoGND............................................-0.3Vto(VCC+0.3V)LXCurrent(Note1).....................................................-9Ato+9ABSTtoLX..................................................................-0.3Vto+6VPGNDtoGND.......................................................-0.3Vto+0.3VContinuousPowerDissipation(TA=+85°C)(derate23.8mW/°Cabove+70°C).............................1191mWOperatingTemperatureRange...........................-40°Cto+85°CStorageTemperatureRange.............................-65°Cto+150°CLeadTemperature(soldering,10s).................................+300°CPARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSIN/VCCInputVoltageVIN2.65.5VVIN=3.3V1220INSupplyCurrentIINSYNC=VCC(1MHz),noloadVIN=5.5V48mAVCC=3.3V23VCCSupplyCurrentICCSYNC=VCC(1MHz)VCC=5.5V3mAVDD=3.3V58VDDSupplyCurrentIDDSYNC=VCC(1MHz)VDD=5.5V10mATotalShutdownCurrentfromIN,VCC,andVDDITOTALVIN=VCC=VDD=VBST-VLX=5.5V,CTL1=CTL2=GND500µAVCCrising2.402.55VCCUndervoltageLockoutThresholdVUVLOWhenLXstarts/stopsswitchingVCCfalling2.202.35VVDDVDDShutdownSupplyCurrentVIN=VDD=VBST=5.5V,VLX=5.5Vor0,CTL1=CTL2=GND10µABSTBSTShutdownSupplyCurrentIBSTVIN=VDD=VBST=5.5V,VLX=5.5Vor0,CTL1=CTL2=GND10µAREFREFVoltageVREFIREF=0,VIN=2.6Vto5.5V1.972.002.04VREFShutdownResistanceFromREFtoGND,CTL1=CTL2=GND10100ΩCOMPFBSEL=High-Z305585FBSEL=GND13.324.437.8COMPTransconductanceFromFBtoCOMP,VCOMP=1.25VFBSEL=VCC9.617.627.2µSCOMPClampVoltageLowVLOW_CLAMPVIN=2.6Vto5.5V,VFB=0.9V0.50.81.1VCOMPClampVoltageHighVHIGH_CLAMPVIN=2.6Vto5.5V,VFB=0.7V1.902.152.40VCOMPShutdownResistanceFromCOMPtoGND,CTL1=CTL2=GND10100ΩNote1:LXhasinternalclampdiodestoPGNDandIN.Applicationsthatforwardbiasthesediodesshouldtakecarenott