TheAAD7999are12-/10-/8-bit,lowpower,successiveapproximationADCswithanI2Ccompatibleinterface.Eachpartoperatesfromasingle2.7Vto5.5Vpowersupplyandfeaturesa1μsconversiontime.Thetrack-and-holdamplifierallowseachparttohandleinputfrequenciesofupto14MHz,andamultiplexerallowstakingsamplesfromfourchannels.

TheAD7999normallyremaininashutdownstate,poweringuponlyforconversions.Theconversionprocessiscontrolledbyacommandmode,duringwhicheachI2CreadoperationinitiatesaconversionandreturnstheresultovertheI2Cbus.

Whenfourchannelsareusedasanaloginputs,thereferenceforthepartistakenfromVDD;thisallowsthewidestdynamicinputrangetotheADC.Therefore,theanaloginputrangetotheADCis0VtoVDD.Anexternalreference,appliedthroughtheVIN3/VREFinput,canalsobeusedwiththispart.