TheAD7904are,respectively,8-bit,10-bit,and12-bit,highspeed,lowpower,4-channelsuccessiveapproxi-mationADCs.Thepartsoperatefromasingle2.7Vto5.25Vpowersupplyandfeaturethroughputratesupto1MSPS.Thepartscontainalownoise,widebandwidthtrack-and-holdamplifierthatcanhandleinputfrequenciesinexcessof8MHz.
TheconversionprocessanddataacquisitionarecontrolledusingCSandtheserialclocksignal,allowingthedevicetoeasilyinter-facewithmicroprocessorsorDSPs.TheinputsignalissampledonthefallingedgeofCSandconversionisalsoinitiatedatthispoint.Therearenopipelinedelaysassociatedwiththepart.
TheAD7904/AD7914/AD7924useadvanceddesigntechniquestoachieveverylowpowerdissipationatmaximumthroughputrates.Atmaximumthroughputrates,theAD7904consume2mAmaximumwith3Vsupplies;with5Vsupplies,thecurrentconsumptionis2.7mAmaximum.
Throughtheconfigurationofthecontrolregister,theanaloginputrangeforthepartcanbeselectedas0VtoREFINor0Vto2×REFIN,witheitherstraightbinaryortwoscomplementoutputcoding.TheAD7904eachfeaturefoursingle-endedanaloginputswithachannelsequencertoallowapre-programmedselectionofchannelstobeconvertedsequentially.
TheconversiontimefortheAD7904isdeterminedbytheSCLKfrequency,whichisalsousedasthemasterclocktocontroltheconversion.
