养殖技术资料_12位-ad574a转换器中英文翻译资料.doc

《养殖技术资料_12位-ad574a转换器中英文翻译资料.doc》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、英文原文12-BitA/DConverterCIRCUITOPERATIONTheAD574Aisacomplete12-bitA/Dconverterwhichrequiresnoexternalcomponentstoprovidethecompletesuccessiveapproximationanalog-to-digitalconversionfunction.AblockdiagramoftheAD574AisshowninFigure1.Figure1.BlockDiagramofAD574A12-BitA-to-DCon

2、verterWhenthecontrolsectioniscommandedtoinitiateaconversion(asdescribedlater),itenablestheclockandresetsthesuccessiveapproximationregister(SAR)toallzeros.Onceaconversioncyclehasbegun,itcannotbestoppedorrestartedanddataisnotavailablefromtheoutputbuffers.TheSAR,timedbythecl

3、ock,willsequencethroughtheconversioncycleandreturnanend-of-convertflagtothecontrolsection.Thecontrolsectionwillthendisabletheclock,bringtheoutputstatusflaglow,andenablecontrolfunctionstoallowdatareadfunctionsbyexternalcommand.Duringtheconversioncycle,theinternal12-bitcurr

4、entoutputDACissequencedbytheSARfromthemostsignificantbit(MSB)toleastsignificantbit(LSB)toprovideanoutputcurrentwhichaccuratelybalancestheinputsignalcurrentthroughthe5kΩ(or10kΩ)inputresistor.Thecomparatordetermineswhethertheadditionofeachsuccessively-weightedbitcurrentcaus

5、estheDACcurrentsumtobegreaterorlessthantheinputcurrent;ifthesumisless,thebitislefton;ifmore,thebitisturnedoff.Aftertestingallthebits,theSARcontainsa12-bitbinarycodewhichaccuratelyrepresentstheinputsignaltowithin1/2LSB.Thetemperature-compensatedburiedZenerreferenceprovides

6、theprimaryvoltagereferencetotheDACandguaranteesexcellentstabilitywithbothtimeandtemperature.Thereferenceistrimmedto10.00volts±0.2%;itcansupplyupto1.5mAtoanexternalloadinadditiontotherequirementsofthereferenceinputresistor(0.5mA)andbipolaroffsetresistor(1mA)whentheAD574Ais

7、poweredfrom±15Vsupplies.IftheAD574Aisusedwith±12Vsupplies,orifexternalcurrentmustbesuppliedoverthefulltemperaturerange,anexternalbufferamplifierisrecommended.AnyexternalloadontheAD574Areferencemustremainconstantduringconversion.Thethin-filmapplicationresistorsaretrimmedto

8、matchthefull-scaleoutputcurrentoftheDAC.Therearetwo5kWinputscalingresistorstoalloweithera10volto