FEATURES4mAto20mACurrentOutputHART®Compatible16-BitResolutionandMonotonicity0.01%IntegralNonlinearity5Vor3VRegulatorOutput2.5Vand1.25VPrecisionReference750AQuiescentCurrentmaxProgrammableAlarmCurrentCapabilityFlexibleHighSpeedSerialInterface16-LeadSOICandPDIPPackagesTheAD421isacomplete,loop-powered,digitalto4mAto20mAconverter,designedtomeettheneedsof***arttran***ittermanufacturersintheIndustrialControlindustry.Itprovidesahighprecision,fullyintegrated,lowcostsolutioninacompact16-leadpackage.TheAD421isidealforextendingtheresolutionof***art4mAto20mAtran***ittersatverylowcost.TheAD421includesaselectableregulatorthatisusedtopoweritselfandotherdevicesinthetran***itter.Thisregulatorprovideseithera+5V,+3.3Vor+3Vregulatedoutputvoltage.Thepartalsocontains+1.25Vand+2.5Vprecisionreferences.TheAD421thuseliminatestheneedforadiscreteregulatorandvoltagereference.Theonlyexternalcomponentsrequiredareanumberofpassivecomponentsandapasstransistortospanlargeloopvoltages.TheAD421canbeusedwithstandardHARTFSKprotocolcommunicationcircuitrywithoutanydegradationinspecifiedperformance.Thehighspeedserialinterfaceiscapableofoperatingat10Mbpsandallowsforsimpleconnectiontocommonly-usedmicroprocessorsandmicrocontrollersviaastandardthree-wireserialinterface.Thesigma-deltaarchitectureoftheDACguarantees16-bitmonotonicitywhiletheintegralnonlinearityfortheAD421is&plu***n;0.01%.Thepartprovidesazeroscale4mAoutputcurrentwith&plu***n;0.1%offseterroranda20mAfull-scaleoutputcurrentwith&plu***n;0.2%gainerror.TheAD421is***ailableina16-lead,0.3inch-wide,plasticDIPandina16-lead,0.3inch-wide,SOICpackage.Thepartisspecifiedovertheindustrialtemperaturerangeof–40°Cto+85°C.)