差分ADC偏置技术技巧和窍门

Truedifferentialconverterscanoffermanyadvantages

oversingle-endedinputA/DConverters(ADC).Inaddi-

tiontotheircommonmoderejectionability,thesecon-

verterscanalsobeusedtoovercomemanyDCbiasing

limitationsofcommonsignalconditioningcircuits.

Listedbelowaresometypicalapplicationissuesthat

canbesolvedwithproperbiasingofadifferentialcon-

verter:

•Limitedoutputswingofamplifiers

•UnwantedDC-biaspoint

•Lowlevelnoiseridingonground

•Unwantedorchangingcommonmodelevelof

inputsignal

Thisapplicationnotediscussesdifferentialinputconfig-

urationsandtheiroperation,circuitstoimplement

theseinputmodesandtechniquesinchoosingthecor-

rectvoltagelevelstoovercomethepreviously

mentionedchallenges.MAN842DifferentialADCBiasingTechniques,TipsandTricksItisimportanttonotethattheconverteroutputiszeroAuthor:CraigL.Kingwhentheinputsareequal.AsthevoltagedifferenceMicrochipTechnologyInc.betweenIN+andIN-increases,theoutputcodealsoincreases.ThemaximumvoltageatwhichdigitalcodeINTRODUCTIONsaturationwilloccurisVREF.Thedifferentialconver-