TheAD9985Aisacomplete8-bit,140MSPS,monolithicanaloginterfaceoptimizedforcapturingRGBgraphicssignalsfrompersonalcomputersandworkstations.Its140MSPSencoderatecapabilityandfullpoweranalogbandwidthof300MHzsupportresolutionsuptoSXGA(1280×1024at75Hz).
TheAD9985Aincludesa140MHztripleADCwithinternal1.25Vreference,aPLL,andprogrammablegain,offset,andclampcontrol.Theuserprovidesonlya3.3Vpowersupply,analoginput,andhorizontalsync(Hsync)andCoastsignals.Three-stateCMOSoutputscanbepoweredfrom2.5Vto3.3V.
TheAD9985A’son-chipPLLgeneratesapixelclockfromtheHsyncinput.Pixelclockoutputfrequenciesrangefrom12MHzto140MHz.PLLclockjitteris500psp-ptypicalat140MSPS.WhentheCOASTsignalispresented,thePLLmaintainsitsoutputfrequencyintheabsenceofHsync.Asamplingphaseadjustmentisprovided.Data,Hsync,andclockoutputphaserelationshipsaremaintained.
TheAD9985alsooffersfullsyncprocessingforcompositesyncandsync-on-greenapplications,variableanaloginputbandwidthcontrol,variableSOGINbandwidthcontrolandselectableinputfiltering.
AclampsignalisgeneratedinternallyorcanbeprovidedbytheuserthroughtheCLAMPinputpin.Thisinterfaceisfullyprogrammableviaa2-wireserialinterface.
FabricatedinanadvancedCMOSprocess,theAD9985Aisprovidedinaspace-saving80-leadLQFPsurface-mountPb-freeplasticpackage,andisspecifiedoverthe–40°Cto+85°Ctemperaturerange.