集成电路外文翻译.docx
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集成电路外文翻译.docx
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集成电路外文翻译
大学
本科生毕业设计(论文)
外文翻译
学院:
专业:
学生:
指导教师:
完成日期:
2012年5月30日
Integratedcircuit(IC)
Introducion
Integratedcircuitalsocalledmicroelectroniccircuitorchipanassemblyofelectroniccomponents,fabricatedasasingleunit,inwhichminiaturizedactivedevices(e.g.,transistorsanddiodes)andpassivedevices(e.g.,capacitorsandresistors)andtheirinterconnectionsarebuiltuponathinsubstrateofsemiconductormaterial(typicallysilicon).Theresultingcircuitisthusasmallmonolithic“chip,”whichmaybeassmallasafewsquarecentimetresoronlyafewsquaremillimetres.Theindividualcircuitcomponentsaregenerallymicroscopicinsize.
Integratedcircuitshavetheiroriginintheinventionofthetransistorin1947byWilliamB.ShockleyandhisteamattheAmericanTelephoneandTelegraphCompany'sBellLaboratories.Shockley'steam(includingJohnBardeenandWalterH.Brattain)foundthat,undertherightcircumstances,electronswouldformabarrieratthesurfaceofcertaincrystals,andtheylearnedtocontroltheflowofelectricitythroughthecrystalbymanipulatingthisbarrier.Controllingelectronflowthroughacrystalallowedtheteamtocreateadevicethatcouldperformcertainelectricaloperations,suchassignalamplification,thatwerepreviouslydonebyvacuumtubes.Theynamedthisdeviceatransistor,fromacombinationofthewordstransferandresistor(seephotograph).Thestudyofmethodsofcreatingelectronicdevicesusingsolidmaterialsbecameknownassolid-stateelectronics.Solid-statedevicesprovedtobemuchsturdier,easiertoworkwith,morereliable,muchsmaller,andlessexpensivethanvacuumtubes.
Usingthesameprinciplesandmaterials,engineerssoonlearnedtocreateotherelectricalcomponents,suchasresistorsandcapacitors.Nowthatelectricaldevicescouldbemadesosmall,thelargestpartofacircuitwastheawkwardwiringbetweenthedevices.
In1958JackKilbyofTexasInstruments,Inc.,andRobertNoyceofFairchildSemiconductorCorporationindependentlythoughtofawaytoreducecircuitsizefurther.Theylaidverythinpathsofmetal(usuallyaluminumorcopper)directlyonthesamepieceofmaterialastheirdevices.Thesesmallpathsactedaswires.Withthistechniqueanentirecircuitcouldbe“integrated”onasinglepieceofsolidmaterialandanintegratedcircuit(IC)thuscreated.ICscancontainhundredsofthousandsofindividualtransistorsonasinglepieceofmaterialthesizeofapea.Workingwiththatmanyvacuumtubeswouldhavebeenunrealisticallyawkwardandexpensive.TheinventionoftheintegratedcircuitmadetechnologiesoftheInformationAgefeasible.ICsarenowusedextensivelyinallwalksoflife,fromcarstotoasterstoamusementparkrides.
BasicICtypes
Analogversusdigitalcircuits
Analog,orlinear,circuitstypicallyuseonlyafewcomponentsandarethussomeofthesimplesttypesofICs.Generally,analogcircuitsareconnectedtodevicesthatcollectsignalsfromtheenvironmentorsendsignalsbacktotheenvironment.Forexample,amicrophoneconvertsfluctuatingvocalsoundsintoanelectricalsignalofvaryingvoltage.Ananalogcircuitthenmodifiesthesignalinsomeusefulway—suchasamplifyingitorfilteringitofundesirablenoise.Suchasignalmightthenbefedbacktoaloudspeaker,whichwouldreproducethetonesoriginallypickedupbythemicrophone.
Anothertypicaluseforananalogcircuitistocontrolsomedeviceinresponsetocontinualchangesintheenvironment.Forexample,atemperaturesensorsendsavaryingsignaltoathermostat,whichcanbeprogrammedtoturnanairconditioner,heater,orovenonandoffoncethesignalhasreachedacertainvalue.
Adigitalcircuit,ontheotherhand,isdesignedtoacceptonlyvoltagesofspecificgivenvalues.Acircuitthatusesonlytwostatesisknownasabinarycircuit.Circuitdesignwithbinaryquantities,“on”and“off”representing1and0(i.e.,trueandfalse),usesthelogicofBooleanalgebra.Thethreebasiclogicfunctions—NOT,AND,andOR—togetherwiththeirtruthtablesaregiveninthefigure.(ArithmeticisalsoperformedinthebinarynumbersystememployingBooleanalgebra.)ThesebasicelementsarecombinedinthedesignofICsfordigitalcomputersandassociateddevicestoperformthedesiredfunctions.
Microprocessorcircuits
MicroprocessorsarethemostcomplicatedICs.Theyarecomposedofmillionsoftransistorsthathavebeenconfiguredasthousandsofindividualdigitalcircuits,eachofwhichperformssomespecificlogicfunction.Amicroprocessorisbuiltentirelyoftheselogiccircuitssynchronizedtoeachother.
Justlikeamarchingband,thecircuitsperformtheirlogicfunctiononlyondirectionbythebandmaster.Thebandmasterinamicroprocessor,sotospeak,iscalledtheclock.Theclockisasignalthatquicklyalternatesbetweentwologicstates.Everytimetheclockchangesstate,everylogiccircuitinthemicroprocessordoessomething.Calculationscanbemadeveryquickly,dependingonthespeed(“clockfrequency”)ofthemicroprocessor.
Microprocessorscontainsomecircuits,knownasregisters,thatstoreinformation.Registersarepredeterminedmemorylocations.Eachprocessorhasmanydifferenttypesofregisters.Permanentregistersareusedtostorethepreprogrammedinstructionsrequiredforvariousoperations(suchasadditionandmultiplication).Temporaryregistersstorenumbersthataretobeoperatedonandalsotheresult.Otherexamplesofregistersincludethe“programcounter,”the“stackpointer,”andthe“address”register.
Microprocessorscanperformmillionsofoperationspersecondondata.Inadditiontocomputers,microprocessorsarecommoninvideogamesystems,televisions,cameras,andautomobiles.
Memorycircuits
Microprocessorstypicallyhavetostoremoredatathancanbeheldinafewregisters.Thisadditionalinformationisrelocatedtospecialmemorycircuits.Memoryiscomposedofdensearraysofparallelcircuitsthatusetheirvoltagestatestostoreinformation.Memoryalsostoresthetemporarysequenceofinstructions,orprogram,forthemicroprocessor.Manufacturerscontinuallystrivetoreducethesizeofmemorycircuits—toincreasecapabilitywithoutincreasingspace.Inaddition,smallercomponentstypicallyuselesspower,operatemoreefficiently,andcostlesstomanufacture.
Digitalsignalprocessors
Asignalisananalogwaveform—anythingintheenvironmentthatcanbecapturedelectronically.Adigitalsignalisananalogwaveformthathasbeenconvertedintoaseriesofbinarynumbersforquickmanipulation.Asthenameimplies,adigitalsignalprocessor(DSP)processessignalsdigitally,aspatternsof1sand0s.Forinstance,usingananalog-to-digitalconverter,commonlycalledanA-to-DorA/Dconverter,arecordingofsomeone'svoicecanbeconvertedintodigital1sand0s.ThedigitalrepresentationofthevoicecanthenbemodifiedbyaDSPusingcomplexmathematicalformulas.Forexample,theDSPalgorithminthecircuitmaybeconfiguredtorecognizegapsbetweenspokenwordsasbackgroundnoiseanddigitallyremoveambientnoisefromthewaveform.Finally,theprocessedsignalcanbeconvertedback(byaD/Aconverter)intoananalogsignalforlistening.Digitalprocessingcanfilteroutbackgroundnoisesofastthatthereisnodiscernibledelayandthesignalappearstobeheardin“realtime.”Forinstance,suchprocessingenables“live”televisionbroadcaststofocusonaquarterback'ssignalsinanAmericangridironfootballgame.DSPsarealsousedtoproducedigitaleffectsonlivetelevision.Forexample,theyellowmarkerlinesdisplayedduringthefootballgamearenotreallyonthefield;aDSPaddsthelinesafterthecamerasshootthepicturebutbeforeitisbroadcast.Similarly,someoftheadvertisementsseenonstadiumfencesandbillboardsduringtelevisedsportingeventsarenotreallythere.
Application-specificICs
Anapplication-specificIC(ASIC)canbeeitheradigitalorananalogcircuit.Astheirnameimplies,ASICsarenotreconfigurable;theyperformonlyonespecificfunction.Forexample,aspeedcontrollerICforaremotecontrolcarishard-wiredtodoonejobandcouldneverbecomeamicroprocessor.AnASICdoesnotcontainanyabilitytofollowalternateinstructions.
Radio-frequencyICs
Radio-frequencyICs(RFICs)arerapidlygainingimportanceincellulartelephonesandpagers.RFICsareanalogcircuitsthatusuallyruninthefrequencyrangeof900MHzto2.4GHz(900millionhertzto2.4billionhertz).TheyareusuallythoughtofasASICseventhoughsomemaybeconfigurableforseveralsimilarapplications.Mostsemiconductorcircuitsthatoperateabove500MHzcausetheelectroniccomponentsandtheirconnectingpathstointerferewitheachotherinunusualways.Engineersmustusespecialdesigntechniquestodealwiththephysicsofhigh-frequencymicroelectronicinteractions.
MicrowavemonolithicICs
AspecialtypeofRFICisknownasamicrowavemonolithicIC(MMIC).Thesecircuitsruninthe2.4-to20-GHzrange,ormicrowavefrequencies,andareusedinradarsystems,insatellitecommunications,andaspoweramplifiersforcellulartelephones.
Justassoundtravelsfasterthroughwaterthanthroughair,electronvelocityisdifferentthrougheachtypeofsemiconductormaterial.Siliconofferstoomuchresistanceformicrowave-frequencycircuits,andsothecompoundgalliumarsenide(GaAs)isoftenusedforMMICs.Unfortunately,GaAsismechanicallymuchlesssoundthansilicon.Itbreakseasily,soGaAswafersareusuallymuchmoreexpensivetobuildthansiliconwafers.
Basicsemiconductordesign
Anymaterialcanbeclassifiedasoneofthreetypes:
conductor,insulator,orsemicondu
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