[模拟cmos集成电路设计].design.of.analog.cmos.

《[模拟cmos集成电路设计].design.of.analog.cmos.》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、Chapter2BasicMOSDevicePhysicsInstudyingthedesignofintegratedcircuits,oneoftwoextremeapproachescanbetaken:(1)beginwithquantummechanicsandunderstandsolid-statephysics,semiconductordevicephysics,devicemodeling,andfinallythedesignofcircuits;(2)treateachsemiconductordeviceasablackboxwhosebeha

2、viorisdescribedintermsofitsterminalvoltagesandcurrentsanddesigncircuitswithlittleattentiontotheinternaloperationofthedevice.Experienceshowsthatneitherapproachisoptimum.Inthefirstcase,thereadercannotseetherelevanceofallofthephysicstodesigningcircuits,andinthesecond,he/sheisconstantlymysti

3、fiedbythecontentsoftheblackbox.Intoday'sICindustry,asolidunderstandingofsemiconductordevicesisessential,moresoinanalogdesignthanindigitaldesignbecauseintheformer,transistorsarenotconsideredassimpleswitchesandmanyoftheirsecond-ordereffectsdirectlyim-pacttheperformance.Furthermore,aseachne

4、wgenerationofICtechnologiesscalesthedevices,theseeffectsbecomemoresignificant.Sincethedesignermustoftendecidewhicheffectscanbeneglectedinagivencircuit,insightintodeviceoperationprovesinvaluable.Inthischapter,westudythephysicsofMOSFETsatanelementarylevel,coveringthebareminimumthatisnecess

5、aryforbasicanalogdesign.TheultimategoaIisstilltodevelopacircuitmodelforeachdevicebyformulatingitsoperation,butthisisac-complishedwithagoodunderstandingoftheunderlyingprinciples.AfterstudyingmanyanalogcircuitsinChapters3through13andgainingmotivationforadeeperunderstandingofdevices,weretur

6、ntothesubjectinChapter16anddealwithotheraspectsofMOSoperation.WebeginourstudywiththestructureofMOStransistorsandderivetheirWchar-acteristics.Next,wedescribesecond-ordereffectssuchasbodyeffect,channel-lengthmodulation,andsubthresholdconduction.WethenidentifytheparasiticcapacitancesofMOSFE

7、Ts,deriveasmall-signalmodel,andpresentasimpleSPICEmodel.Weas-sumethatthereaderisfamiliarwithsuchbasicconceptsasdoping,mobility,andpnjunctions.