ADIAD5933高精度阻抗测量解决方案CN0217

ADIAD5933高精度阻抗测量解决方案CN0217关键字：工业控制,测试仪表,阻抗测量ADI公司的高精度阻抗测量解决方案CN0217采用12位阻抗转换器AD5933/AD5934.AD5933是1MSPS的12位ADC,而AD5934是250KSPS的12位ADC,内部集成了温度传感器(±2°C),系统精度0.5%,工作电压2.7V-5.5V,图1的电路优化了信号链,其阻抗测量范围从低欧姆数到几百kΩ,主要用在电化学分析,生物阻抗分析,复数阻抗分析,生物和汽车传感器,接近式检测,非破坏性检测,以及材料特性分析和燃料/电池状态监视等.本文介绍了AD5933主要特性,功能方框图,病毒株血样本测量框图和AD5933评估板主要特性,电路图与材料清单.TheAD5933andAD5934arehighprecisionimpedanceconvertersystemsolutionsthatcombineanon-chipprogrammablefrequencygeneratorwitha12-bit,1MSPS(AD5933)or250kSPS(AD5934)analog-to-digitalconverter(ADC).Thetunablefrequencygeneratorallowsanexternalcompleximpedancetobeexcitedwithaknownfrequency.ThecircuitshowninFigure1yieldsaccurateimpedancemeasurementsextendingfromthelowohmrangetoseveralhundredkΩandalsooptimizestheoverallaccuracyoftheAD5933/AD5934.图1.高精度阻抗测量优化信号链的电路图TheAD5933isahighprecisionimpedanceconvertersystemsolutionthatcombinesanon-boardfrequencygeneratorwitha12-bit,1MSPS,analog-to-digitalconverter(ADC).Thefrequencygeneratorallowsanexternalcompleximpedancetobeexcitedwithaknownfrequency.Theresponsesignalfromtheimpedanceissampledbytheon-boardADCandadiscreteFouriertransform(DFT)isprocessedbyanon-boardDSPengine.TheDFTalgorithmreturnsareal(R)andimaginary(I)data-wordateachoutputfrequency.Oncecalibrated,themagnitudeoftheimpedanceandrelativephaseoftheimpedanceateachfrequencypointalongthesweepiseasilycalculated.Thisisdoneoffchipusingtherealandimaginaryregistercontents,whichcanbereadfromtheserialI2Cinterface.Asimilardevice,alsoavailablefromAnalogDevices,Inc.,istheAD5934,a2.7Vto5.5V,250kSPS,12-bitimpedanceconverter,withaninternaltemperaturesensorandispackagedina16-leadSSOP.AD5933主要特性:Programmableoutputpeak-to-peakexcitationvoltagetoamaximumfrequencyof100kHzProgrammablefrequencysweepcapabilitywithserialI2CinterfaceFrequencyresolutionof27bits(0.1Hz)Impedancemeasurementrangefrom1kΩto10MΩCapableofmeasuringof100Ωto1kΩwithadditionalcircuitryInternaltemperaturesensor(±2℃)InternalsystemclockoptionPhasemeasurementcapabilitySystemaccuracyof0.5%2.7Vto5.5VpowersupplyoperationTemperaturerange:−40℃to+125℃16-leadSSOPpackageAD5933应用:ElectrochemicalanalysisBioelectricalimpedanceanalysisImpedancespectroscopyCompleximpedancemeasurementCorrosionmonitoringandprotectionequipmentBiomedicalandautomotivesensorsProximitysensingNondestructivetestingMaterialpropertyanalysisFuel/batterycellconditionmonitoring图2.AD5933功能方框图图3.采用AD5933的病毒株血样本测量框图AD5933评估板ThisdocumentdescribestheevaluationboardfortheAD5933andtheapplicationsoftwaredevelopedtointerfacetothedevice.TheAD5933isahighprecisionimpedanceconvertersystemthatcombinesanon-boardfrequencygeneratorwitha12-bit,1MSPSADC.Thefrequencygeneratorallowsanexternalcompleximpedancetobeexcitedwithaknownfrequency.Theresponsesignalfromtheimpedanceissampledbytheon-boardADC,andtheDFTisprocessedbyanon-boardDSPengineateachexcitationfrequency.TheAD5933alsocontainsaninternaltemperaturesensorwith13-bitresolutionandoperatesfroma2.7Vto5.5Vsupply.Otheron-boardcomponentsincludeanADR4233.0VreferencethatactsasastablesupplyvoltagefortheseparateanaloganddigitalsectionsofthedeviceandanADP3303ultrahighprecisionregulatorthatactsasasupplytotheon-boarduniversalserialbuscontroller,whichinterfacestotheAD5933.TheusercanpowertheentirecircuitryfromtheUSBportofacomputer.Theevaluationboardalsohasahighperformance,trimmed,16MHz,surface-mountcrystalthatcanactasasystemclockfortheAD5933,ifrequired.ThevariouslinkoptionsavailableontheevaluationboardareexplainedinTable2.InterfacingtotheAD5933isthroughaUSBmicrocontroller,whichgeneratestheI2CsignalsnecessarytocommunicatewiththeAD5933.TheuserinterfacestotheUSBmicrocontrollerthroughaVisualBasic®graphicuserinterfacelocatedonandrunfromtheuserPC.MoreinformationontheAD5933isavailablefromAnalogDevices,Inc.,at评估板主要特性:Full-featuredevaluationboardfortheAD5933GraphicuserinterfacesoftwarewithfrequencysweepcapabilityforboardcontrolanddataanalysisVariouspowersupplylinkingoptionsStandalonecapabilitywithserialI2Cloadingfromon-boardmicrocontrollerSelectablesystemclockoptions,includinginternalRCoscillatororon-board16MHzcrystalAD5933评估板应用:ElectrochemicalanalysisImpedancespectroscopyCompleximpedancemeasurementCorrosionmonitoringandprotectionequipmentBiomedicalandautomotivesensorsProximitysensing图4.AD5933评估板方框图图5.EVAL-CN0217-EBIZ电路图(1)AO-Electronics傲壹电子官网：中文网：电路图(2)ALPSADIIRJRC/NJRKECOTAXSeoulSemiconductorTIWalsinTechnology图7.EVAL-CN0217-EBIZ电路图(3)