IC datasheet pdf-GC1115,pdf(Crest Factor Reduction

1FEATURESAPPLICATIONSDESCRIPTIONGC1115–FEBRUARY2005–REVISEDAPRIL2009CrestFactorReductionProcessor•3GPP(W-CDMA,HSDPA)BaseStations23•ReducesSignalPeaksto≥6dBPAR•3GPP2(cdma2000)BaseStations•One-andTwo-ChannelOperation•TDSCDMABaseStations•ProgrammablePARWithFourStages•PAPRReductionofOFDM,Wibro,OFDMA•ProgrammableCancellationPulseCoefficientsSignals•256-BallPBGAPackage,17-mm×17-mm•Two-ChannelTransmitDiversityApplications•1.2-VCore,3.3VI/O•OperatesWithTIDAC5687(500Msps)TheGC1115isaflexible,programmable,widebandcrestfactorreduction(CFR)processorwithamaximumcompositebandwidthof32MHz(4clocks/complexsample,onechannel)or16MHz(8clocks/complexsample,twochannels).TheGC1115selectivelyreducesthepeak-to-averageratio(PAR)ofwidebanddigitalsignalsprovidedinquadrature(IandQ)format.ByreducingthePARofdigitalsignals,theefficiencyoffollow-onpoweramplifiers(PAs)isimproved,theD/Aconverterrequirementsareeased,andtheout-of-bandspectralregrowthcausedbysimplehardlimitingiseliminated.Manufacturersof3GBTSequipmentcanrealizesignificantsavingsonpoweramplifiercostsbyincludingtheGC1115.TheGC1115meetsmulticarrier3Gperformancestandards(PCDE,compositeEVM,andACLR)atPARlevelsdownto6dB.TheGC1115integrateseasilyintothetransmitsignalchain,betweenadigitalupconvertersuchastheTexasInstrumentsGC5016orGC5316andahigh-qualityD/Aconverter,suchastheTexasInstrumentsDAC5687.theGC1115canbeinterleavedorparallelcomplex.TheGC1115usesfourcascadedstagesofpeakdetectionandcancellation(PDC)toremoveover-thresholdpeaksfromtheinputsignal.EachPDCstagecanbeindependentlyprogrammedwithdetectiontargetpeaklevelsandcancellationpulsecoefficients.Apoolof32cancellationpulsegeneratorscanbeflexiblyassignedingroupsof4toanyPDCstage.RealorcomplexFIRcancellationcoefficientsarepreprocessedintocoefficientsandderivativevalues.Cancellationpulsesaredesignedtomatchtheuser’scarrierfrequencyallocation.Cancellationpulseenergyisbandlimitedandthusisonlyaddedwithinallocatedcarrierbands.TheGC1115peakcancellationalgorithmhasminimaleffectontheACLRofthesignal.TheCFRdatacanbeinterpolatedandoutputincomplexorrealformats.Inputsamplingratesto130Mspsaresupported,ineitherparallelormultiplexedI/Qmodes,andineither2scomplementorunsignedformat.TheGC1115includesaninterpolatorthatincreasestheoutputsamplingrateby2×or4×andoptionallymodulatestheoutputsignaltothefs/4centerfrequency.Outputsamplingratesto130MspsaresupportedineitherparallelormultiplexedI/Qmodes,andineither2scomplementorunsignedformat.Aspecialone-channel,2×outputmodeusesbothGC1115outputportstocarryodd/evenrealoutputsamples.Dualon-chipRAMprovideseithertime-domainsnapshotsorlong-termhistogrammingoftheinternalpeakcancellationsignalchainatfiveuser-selectedpoints,enablingreal-timemonitoringoftheCCDFfunction.Apower-levelmetermonitorseithertheGC1115inputoroutputpowerlevel.1Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.2MATLABisaregisteredtrademarkofTheMathWorks,Inc.3Allothertrademarksarethepropertyoftheirrespectiveowners.PRODUCTIONDATAinformationiscurrentasofpublicationdate.Copyright©2005–2009,TexasInstrumentsIncorporatedProductsconformtospecificationsperthetermsoftheTexasInstrumentsstandardwarranty.Productionprocessingdoesnotnecessarilyincludetestingofallparameters.PDCStage1PDCStage2PDCStage3PDCStage4Interp2,4+f/4´´SSoftLimiterandOutputFormatIN_A[17:0]IN_B[17:0]IN_CLK32CancellationPulseGenerators(AllocatetoPDCStagesinGroupsof4)VDDA1VSSA1VDDA2VSSA2CORE_CLKVDD(40)VSS(64)VDDSHV(31)TestSignalGeneratorSnapshotRAMInputSelectorA[7:0]D[15:0]OUT_A[17:0]OUT_B[17:0]OUT_IQ_SELLOOP(NC)PLL_TXJTAG[4:0]TEST_MODEVPPPLL_COREVSS1VDD1SnapshotRAMASnapshotRAMBMicroprocessorRegistersOUT_CLK(NC)CRCGen.SyncControlPowerMeasurementCSRDWRINTRESETSYNC_BSYNC_ASYNC_OUTB0182-01GC1115SLWS144D–FEBRUARY2005–REVISEDAPRIL2009.................................................................................................................................................–40Cto85C256-PBGAPlasticBallGridArrayGC1115IZDJ2SubmitDocumentationFeedbackCopyright©2005–2009,TexasInstrumentsIncorporatedProductFolderLink(s):GC1115INTRODUCTIONB0056-01D/APAGC5016,GC5316,orOtherDUCMicro-processororTIDSPGC1115RFUpconversionWhyCancelPeaks?GC1115–FEBRUARY2005–REVISEDAPRIL2009Figure1showsthetypicalusageoftheGC1115crestfactorreductionprocessorinthetransmitsignalchainofawirelessbasestation.Figure1.WirelessSystemUsingtheGC1115TheGC1115isinitializedandcontrolledusingan8-bitaddress(A)busanda16-bitdata(D)bus.Thesepins,alongwiththeread(RD),write(WR),andchipselect(CS)pins,allowuserstomodifythecontrolregi