基于标准CMOS工艺的ISFET生物微传感SOC的信号读取电路研究

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1、密级编号中国科学院研究生院博士学位论文＼987864基王拯准￡丛Q＆王苎数兰&星量!生物邀佳盛SQg申请学位级别擅±学科专业名称物堡电王堂论文提交日期2QQ鱼生垒旦论文答辩日期2QQ鱼生量旦AbstractBiosensorSOCcanbewidelyusedintheareassuchaslifescience．biomedicalengineering，foodindustry，healthcare，environmentmonitoring，andSOon，Becauseofitsimportance．thetopicisattractingtremendousresearche

2、fforttoday。However，therealizationofthebiosensorSOCstillfaceswithmanychallenges．ThisdissertationpresentsathoroughstudyonamonolithicintegrationofISFETsensorsandreadoutelectronics，aimingatobtainingpropersignalconditionforfllrtherA／Dconversion．Inthisdissertation，theoperationprincipleoftheISFEThasbee

3、nstudiedandthe“floatinggate”structurefortheISFETisdescribed．TheTa205passivationlayerdepositedonthegateactsasthepH—sensitivematerial．Together，aSPICEmodeloftheISFETiSbuiltforcircuitsimulation．EmphasisofthisdissertationisplacedontheresearchintothesensorreadoutsystemcontainingISFET／REFET(referenceFE

4、T)pairandthebufferamplifiersaswellasareferenceelectrodestructurebasedonCMOStechnology．Whenthereadoutsystemisinoperation，twoamplifiersareemployedtoeachdetectISFETandREFETsignals．Thedifferenceofthetwosignalswillbeprocessedthxoughavoltagetocurrentconverterthatisimplementedwithanovelcircuitstructure

5、．ThisconvertercircuitissuitableforimpedancematchingbetweenthecascadingstagesoftheCMOSreadoutsystemandcandeliverlargedynamicrange．Therefore，theprocessedsignalshouldbeeasilytakenbytheA／Dconvener．UsuallytheinputoffsetvoltageofapracticaloperationalamplifierisveryIarge(typicallyintheorderofmagnitudeo

6、f1-10mV)．Thisdissertationpresentsanauto．zerostabilizationtechniquethatisforthefirsttimeusedtodevelopthehi曲precisionop·ampforISFET’Ssignaldetection．ThistechniqueCansignificantlyreducetheoffset，temperaturedriftandlowfrequencynoiseoftheop—amp．Theop，ampsupplysconstantbiasconditionsfortheISFETsensorw

7、hichCallworkineitherlinearorsaturationregionbyprogrammablecontr01．TheamplifiermaintainsaDCopenloopgainofmorethan140dBandanoffsetvoltageoflessthan10uV．AbstraclThesensorchipisfabricatedinastandardO．35pmCMOSprocess(CharteredSem