TheAD9869isamixed-signalfront-end(MxFE®)ICfortransceiverapplicationsrequiringTxpathandRxpathfunctionalitywithdataratesupto80MSPS.Alowercost,pin-compatibleversionofthe
Thepartiswellsuitedforhalf-andfull-duplexapplications.Thedigitalinterfaceisextremelyflexible,allowingsimpleinterfacingtodigitalbackendsthatsupporthalf-orfull-duplexdatatransfers,oftenallowingtheAD9869toreplacediscreteADCandDACsolutions.Power-savingmodesincludetheabilitytoreducepowerconsumptionofindividualfunctionalblocksorpowerdownunusedblocksinhalf-duplexapplications.Aserialportinterface(SPI)allowssoftwareprogrammingofthevariousfunctionalblocks.Anon-chipPLLclockmultiplierandsynthesizerprovidealltherequiredinternalclocks,aswellastwoexternalclocks,fromasinglecrystalorclocksource.
TheTxsignalpathconsistsofa2×/4×low-passinterpolationfilter,a12-bitTxDAC,andalinedriver.Thetransmitpathsignalbandwidthcanbeashighas34MHzataninputdatarateof80MSPS.TheTxDACprovidesdifferentialcurrentoutputsthatcanbesteereddirectlytoanexternalloadortoaninternallowdistortioncurrentamplifier(IAMP)capableofdelivering17dBmpeaksignalpower.Txpowercanbedigitallycontrolledovera19.5dBrangein0.5dBsteps.
Thereceivepathconsistsofaprogrammableamplifier(RxPGA),atunablelow-passfilter(LPF),anda12-bitADC.ThelownoiseRxPGAhasaprogrammablegainrangeof−12dBto+48dBin1dBsteps.Itsinputreferrednoiseislessthan3nV/√Hzforgainsettingsbeyond36dB.ThereceivepathLPFcutofffrequencycanbesetovera15MHzto35MHzrangeoritcanbesimplybypassed.The12-bitADCachievesexcellentdynamicperformanceuptoan80MSPSspan.BoththeRxPGAandtheADCofferscalablepowerconsumptionallowingpower/performanceoptimization.
TheAD9869providesahighlyintegratedsolutionformanybroadbandmodems.Itisavailableinaspace-savingpackage,a16-leadLFCSP,andisspecifiedoverthecommercialtemperaturerange(−40°Cto+85°C).