Texas Instruments LM3253 Bedienungsanleitung

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LM3253

www.ti.com

SNVS791Q–FEBRUARY2012–REVISEDMAY2013

LM3253High-CurrentStep-DownConverterfor2G/3G/4GRFPowerAmplifiers

CheckforSamples:LM3253

1

FEATURES

2

•High-EfficiencyPFMandPWMModeswith

DESCRIPTION

InternalSynchronousRectification

TheLM3253isaDC-DCconverteroptimizedfor

poweringmulti-mode2G/3G/4GRFpoweramplifiers

•AnalogBypassFunctionwithLowDropout

(PAs)fromasingleLithium-Ioncell.TheLM3253

Resistance(45mΩtyp.)

stepsdownaninputvoltagefrom2.7Vto5.5Vtoa

•DynamicallyAdjustableOutputVoltage,0.4V

dynamicallyadjustableoutputvoltageof0.4Vto3.6V.

to3.6V(typ.),inPFMandPWMmodes

TheoutputvoltageissetthroughaVCONanalog

•3AMaximumLoadCurrentinPWMMode

inputthatadjuststheoutputvoltagetoensure

efficientoperationatallpowerlevelsoftheRFPA.

•2.7MHz(average)PWMSwitchingFrequency

TheLM3253isoptimizedforUSBdatacard

•ModulatedSwitchingFrequencytoAidRx

applications.

BandCompliance

TheLM3253operatesinconstantfrequencyPulse

•OperatesFromaSingleLi-ionCell

WidthModulation(PWM)modeproducingasmall

(2.7Vto5.5V)

andpredictableamountofoutputvoltageripple.This

•ACBReducesInductorRequirementsandSize

enablesbestECTELpowerrequirementsinGMSK

andEDGEspectralcompliance,withtheminimal

•MinimumTotalSolutionSizebyUsingSmall

amountoffilteringandexcessheadroom.When

FootprintandCaseSizeInductorand

operatinginPulseFrequencyModulation(PFM)

Capacitors

mode,theLM3253enablesthelowestDG09current

•16-bumpThinDSBGAPackage

consumptionandthereforemaximizessystem

•CurrentandThermalOverloadProtection

efficiency.

TheLM3253hasauniqueActiveCurrentassistand

APPLICATIONS

analogBypass(ACB)featuretominimizeinductor

sizewithoutanylossofoutputregulationforthe

•USBDatacards

entirebatteryvoltageandRFoutputpowerrange,

•CellularPhones

untildropout.ACBprovidesaparallelcurrentpath,

•Hand-HeldRadios

whenneeded,tolimitthemaximuminductorcurrent

•RFPCCardsto1.84A(typ.)whilestilldrivinga3Aload.TheACB

alsoenablesoperationwithminimaldropoutvoltage.

•Battery-PoweredRFDevices

TheLM3253isavailableinasmall2mmx2mm

chip-scale16-bumpDSBGApackage.

WhenconsideringtheuseoftheLM3253inasystem

design,contacttheTexasInstrumentsSalesorField

Applicationengineerforacopyofthe"LM3253:

DC-DCConverterfor3G/4GRFPAsPCBLayout

Considerations.”

1

Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsof

TexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.

2Alltrademarksarethepropertyoftheirrespectiveowners.

PRODUCTIONDATAinformationiscurrentasofpublicationdate.

Copyright©2012–2013,TexasInstrumentsIncorporated

ProductsconformtospecificationsperthetermsoftheTexas

Instrumentsstandardwarranty.Productionprocessingdoesnot

necessarilyincludetestingofallparameters.

Produktspezifikationen