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首页 教你如何看懂芯片资料(Datasheet)

教你如何看懂芯片资料(Datasheet).pdf

教你如何看懂芯片资料(Datasheet)

西贝青青
2011-05-23 0人阅读 举报 0 0 暂无简介

简介:本文档为《教你如何看懂芯片资料(Datasheet)pdf》,可适用于工程科技领域

HowtoReadaDatasheetPreparedfortheWIMSoutreachprogram,DGroverInordertouseaPICmicrocontroller,aflipflop,aphotodetector,orpracticallyanyelectronicdevice,youneedtoconsultadatasheetThisisthedocumentthatthemanufacturerprovidestellingyou•thetypicaldeviceperformance•minimumandmaximumrequirementsandcharacteristics•whatyoucandotothedevicewithoutharmingit•suggestedusesandhintsManufacturerswantyou,thedesigner,tohaveasuccessfulexperiencewiththeirdeviceTheyaretryingtobehelpfulTheydon’talwayssucceedThedatasheetonthefollowingpagesisarelativelygooddatasheetIttriestoconciselytellyoueverythingyouneedtoknowaboutthedevice,acommontimerchip(theducttapeoftheelectronicshobbyist)MostdatasheetsforICsfollowthesamegenerallayoutYoudon’thavetounderstandeverythinginadatasheetThere’salotofinformationthatmightnotbeofanyusetoyouTheannotationsthatfollowtrytopointoutpartsofthedatasheetthatyoushouldpayparticularattentiontoWheredoyoufinddatasheetsNowadaysyoucanfindalmostanydatasheetontheinternet,ofteninPDF(Acrobat)formForexample,theLMdatasheetfromNationalSemiconductorisontheirwebsiteatwwwnationalcomWhatistheLMTheLMisatimerchipthatusesexternalresistorsandcapacitorstogenerateeitherasinglepulseofacertainduration,oracontinuoussequenceofpulseswithavarietyofpulsewidthspossibleBecauseitisaverygeneralpurposecollectionoffunctionalblockssuchascomparators,aflipflop,internalvoltagedivider,highpoweroutputstage,andsoon,anumberofdifferenttimingrelatedfunctionsarepossibleEntirebookshavebeenwrittenaboutthe,thoughitisoftenusedwhenanotherICwouldworkbetter(SeeforexampletheCDtimerchip)HYLZh高亮HYLZh线条HYLZh线条LMTimerGeneralDescriptionTheLMisahighlystabledeviceforgeneratingaccuratetimedelaysoroscillationAdditionalterminalsareprovidedfortriggeringorresettingifdesiredInthetimedelaymodeofoperation,thetimeispreciselycontrolledbyoneexternalresistorandcapacitorForastableoperationasanoscillator,thefreerunningfrequencyanddutycycleareaccuratelycontrolledwithtwoexternalresistorsandonecapacitorThecircuitmaybetriggeredandresetonfallingwaveforms,andtheoutputcircuitcansourceorsinkuptomAordriveTTLcircuitsFeaturesnDirectreplacementforSENEnTimingfrommicrosecondsthroughhoursnOperatesinbothastableandmonostablemodesnAdjustabledutycyclenOutputcansourceorsinkmAnOutputandsupplyTTLcompatiblenTemperaturestabilitybetterthanper˚CnNormallyonandnormallyoffoutputnAvailableinpinMSOPpackageApplicationsnPrecisiontimingnPulsegenerationnSequentialtimingnTimedelaygenerationnPulsewidthmodulationnPulsepositionmodulationnLinearrampgeneratorSchematicDiagramDSFebruaryLMTimer©NationalSemiconductorCorporationDSwwwnationalcomDaleGroverTherewillalwaysbeadateDatasheetsdochange,especiallyifPreliminaryorAdvanceCheckthedate!DaleGroverLookupheretoseeifthedatasheetisAdvanceInformationorPreliminaryDaleGroverSometimestheGeneralDescriptionwilltellyouaboutafeatureorusagenotmentionedanywhereelse!Forexample,youmightneedtoholdaspecificpinlowforsomeoperationDaleGroverFeaturestellyougeneralcharacteristicsalwayschecktheElectricalCharacteristicsforconditionsandexceptionsDaleGroverUsuallycalledtheEquivalentSchematicDiagram,thisschematicisn'twhatisnecessarilyinthedevice,butthedeviceactsasifthiswaswhatwasinsideItcanhelpexplainbehaviorthatisn'totherwisedescribedinthedatasheetCouldyouduplicatethiscircuitonabreadboardOnlyifyouknewwhatthecharacteristicsofthetransistorswerewhicharenotgivenDaleGroverDaleGroverDaleGroverDaleGroverDaleGroverDaleGroverApplicationsuggestionscanoftentellyouquicklyifthisdeviceisintheballparkforwhatyouwanttodo,buttheselistsareoftenverygeneralDaleGroverDaleGroverConnectionDiagramOrderingInformationPackagePartNumberPackageMarkingMediaTransportNSCDrawingPinSOICLMCMLMCMRailsMALMCMXLMCMkUnitsTapeandReelPinMSOPLMCMMZkUnitsTapeandReelMUAALMCMMXZkUnitsTapeandReelPinMDIPLMCNLMCNRailsNEDualInLine,SmallOutlineandMoldedMiniSmallOutlinePackagesDSTopViewLMwwwnationalcomDaleGroverMakesureyou'relookingatthepinoutforthecorrectpackageInthebackpagesyou'llfinddrawingsofthepackagetypesHereallthepackageshavethesamepinoutthat'snotalwaysthecase!DaleGroverUnderOrderingInformationyou'llfindalistofeveryvariationofthisdevicealongwiththeCOMPLETEpartnumberOftenthefirstfewlettersareeitherindustrystandardoridentifythemanufacturer(eg,PIC)Thegenericidentifiercomesnext("")Suffixesgenerallygivepackagetype(surfacemountandthroughholetypes),temperaturerange(widerrange=moreexpensive),speed(faster=moreexpensive),andothervariationssuchaspower,voltagerange,etcDaleGroverOtherelementsindatasheets:Relateddevices,suchasdevicesthissupercedes,exactlyreplaces,orisreplacedbyBlockdiagramsofinternalsInformationtosupportprogrammingorconfiguringthedevice(registers,etc)Interfacingwithotherdevices(includinginputoutputcharacteristics)DaleGroverDaleGroverAbsoluteMaximumRatings(Note)IfMilitaryAerospacespecifieddevicesarerequired,pleasecontacttheNationalSemiconductorSalesOfficeDistributorsforavailabilityandspecificationsSupplyVoltageVPowerDissipation(Note)LMCM,LMCNmWLMCMMmWOperatingTemperatureRangesLMC˚Cto˚CStorageTemperatureRange−˚Cto˚CSolderingInformationDualInLinePackageSoldering(Seconds)˚CSmallOutlinePackages(SOICandMSOP)VaporPhase(Seconds)˚CInfrared(Seconds)˚CSeeAN“SurfaceMountingMethodsandTheirEffectonProductReliability”forothermethodsofsolderingsurfacemountdevicesElectricalCharacteristics(Notes,)(TA=˚C,VCC=VtoV,unlessothewisespecified)ParameterConditionsLimitsUnitsLMCMinTypMaxSupplyVoltageVSupplyCurrentVCC=V,RL=∞VCC=V,RL=∞(LowState)(Note)mATimingError,MonostableInitialAccuracyDriftwithTemperatureRA=ktokΩ,ppm˚CC=µF,(Note)AccuracyoverTemperatureDriftwithSupplyVTimingError,AstableInitialAccuracyDriftwithTemperatureRA,RB=ktokΩ,ppm˚CC=µF,(Note)AccuracyoverTemperatureDriftwithSupplyVThresholdVoltagexVCCTriggerVoltageVCC=VVVCC=VVTriggerCurrentµAResetVoltageVResetCurrentmAThresholdCurrent(Note)µAControlVoltageLevelVCC=VVCC=VVPinLeakageOutputHighnAPinSat(Note)OutputLowVCC=V,I=mAmVOutputLowVCC=V,I=mAmVLMwwwnationalcomDaleGroverAbsoluteMaximumRatingstellyouwhatwilldamagethechipNOTthemaximumoperatinglimits!DaleGroverDaleGroverSeeNotefordetailsDaleGroverDaleGroverDaleGroverDaleGroverDaleGroverDaleGroverElectricalCharacteristicsaresometimessplitintoDC(powersupply,staticinputouputcharacteristics)andACorTiming,thesetellyouwhatyoucancountonDaleGroverDesigntotheminimumandmaximumlimits,nottothetypicalThisgivesyouanideaofthelikelybehavior,butnottheworstcaseGood,robustdesigndoesnotcountonthetypical!DaleGroverDaleGroverDaleGroverDaleGroverDaleGroverDaleGroverWatchoutthedatasheetmightdiscussmorethanonepart!DaleGroverDaleGroverPayattentiontotheconditionsnotedHerethedeviceisataspecifictemperatureOften,plotslateroninthedatasheetwillshowtemperaturerelatedparameters(aswellasthosedependentonsupplyvoltage,speed,etc)ElectricalCharacteristics(Notes,)(Continued)(TA=˚C,VCC=VtoV,unlessothewisespecified)ParameterConditionsLimitsUnitsLMCMinTypMaxOutputVoltageDrop(Low)VCC=VISINK=mAVISINK=mAVISINK=mAVISINK=mAVVCC=VISINK=mAVISINK=mAVOutputVoltageDrop(High)ISOURCE=mA,VCC=VVISOURCE=mA,VCC=VVVCC=VVRiseTimeofOutputnsFallTimeofOutputnsNote:Allvoltagesaremeasuredwithrespecttothegroundpin,unlessotherwisespecifiedNote:AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccurOperatingRatingsindicateconditionsforwhichthedeviceisfunctional,butdonotguaranteespecificperformancelimitsElectricalCharacteristicsstateDCandACelectricalspecificationsunderparticulartestconditionswhichguaranteespecificperformancelimitsThisassumesthatthedeviceiswithintheOperatingRatingsSpecificationsarenotguaranteedforparameterswherenolimitisgiven,however,thetypicalvalueisagoodindicationofdeviceperformanceNote:Foroperatingatelevatedtemperaturesthedevicemustbederatedabove˚Cbasedona˚Cmaximumjunctiontemperatureandathermalresistanceof˚CW(DIP),˚CW(S),and˚CW(MSOP)junctiontoambientNote:SupplycurrentwhenoutputhightypicallymAlessatVCC=VNote:TestedatVCC=VandVCC=VNote:ThiswilldeterminethemaximumvalueofRARBforVoperationThemaximumtotal(RARB)isMΩNote:NoprotectionagainstexcessivepincurrentisnecessaryprovidingthepackagedissipationratingwillnotbeexceededNote:RefertoRETSXdrawingofmilitaryLMHandLMJversionsforspecificationsLMwwwnationalcomDaleGrover(HereisNoteinlargeprint)Note:AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccurOperatingRatingsindicateconditionsforwhichthedeviceisfunctional,butdonotguaranteespecificperformancelimitsElectricalCharacteristicsstateDCandACelectricalspecificationsunderparticulartestconditionswhichguaranteespecificperformancelimitsThisassumesthatthedeviceiswithintheOperatingRatingsSpecificationsarenotguaranteedforparameterswherenolimitisgiven,however,thetypicalvalueisagoodindicationofdeviceperformanceDaleGroverTypicalPerformanceCharacteristicsMinimuimPulseWidthRequiredforTriggeringDSSupplyCurrentvsSupplyVoltageDSHighOutputVoltagevsOutputSourceCurrentDSLowOutputVoltagevsOutputSinkCurrentDSLowOutputVoltagevsOutputSinkCurrentDSLowOutputVoltagevsOutputSinkCurrentDSLMwwwnationalcomDaleGroverGraphsareusedtodescribecharacteristicsthatcan'tbecapturedeasilyinatableOftenseveralthingsarebeingvariedabove,supplycurrentismeasuredasvoltageischanged,butthisisalsobeingshowforthreedifferenttemperaturesNotethatCisroughlyroomtemperature(F)DaleGroverPageofthedatasheetisomittedDaleGroverApplicationsInformationMONOSTABLEOPERATIONInthismodeofoperation,thetimerfunctionsasaoneshot(Figure)TheexternalcapacitorisinitiallyhelddischargedbyatransistorinsidethetimerUponapplicationofanegativetriggerpulseoflessthanVCCtopin,theflipflopissetwhichbothreleasestheshortcircuitacrossthecapacitoranddrivestheoutputhighThevoltageacrossthecapacitorthenincreasesexponentiallyforaperiodoft=RAC,attheendofwhichtimethevoltageequalsVCCThecomparatorthenresetstheflipflopwhichinturndischargesthecapacitoranddrivestheoutputtoitslowstateFigureshowsthewaveformsgeneratedinthismodeofoperationSincethechargeandthethresholdlevelofthecomparatorarebothdirectlyproportionaltosupplyvoltage,thetiminginternalisindependentofsupplyDuringthetimingcyclewhentheoutputishigh,thefurtherapplicationofatriggerpulsewillnoteffectthecircuitsolongasthetriggerinputisreturnedhighatleastµsbeforetheendofthetimingintervalHoweverthecircuitcanberesetduringthistimebytheapplicationofanegativepulsetotheresetterminal(pin)TheoutputwillthenremaininthelowstateuntilatriggerpulseisagainappliedWhentheresetfunctionisnotinuse,itisrecommendedthatitbeconnectedtoVCCtoavoidanypossibilityoffalsetriggeringFigureisanomographforeasydeterminationofR,CvaluesforvarioustimedelaysNOTE:Inmonostableoperation,thetriggershouldbedrivenhighbeforetheendoftimingcycleASTABLEOPERATIONIfthecircuitisconnectedasshowninFigure(pinsandconnected)itwilltriggeritselfandfreerunasamultivibratorTheexternalcapacitorchargesthroughRARBanddischargesthroughRBThusthedutycyclemaybepreciselysetbytheratioofthesetworesistorsInthismodeofoperation,thecapacitorchargesanddischargesbetweenVCCandVCCAsinthetriggeredmode,thechargeanddischargetimes,andthereforethefrequencyareindependentofthesupplyvoltageDSFIGUREMonostableDSVCC=VTopTrace:InputVDivTIME=msDIVMiddleTrace:OutputVDivRA=kΩBottomTrace:CapacitorVoltageVDivC=µFFIGUREMonostableWaveformsDSFIGURETimeDelayDSFIGUREAstableLMwwwnationalcomDaleGroverNotalldatasheetapplicationexamplesaresowellwrittensometimesyoujustgettherawschematicsFormorecomplexdevices,suchasmicrocontrollers,differentaspectsmightbehandledindifferentsectionsforexample,aclockcircuitinonepart,aresetcircuitinanotherReadoverallthesectionstomakesureyouareusingthedevicecorrectlyandhavesuppliedallthenecessarycomponentsDaleGroverHereareexamplecircuitsandapplicationnotesNotetoothatoftenthereareothersourcesforapplicationinformation,suchasseparateApplicationNotesavailablefromthemanufacturerDaleGroverThesewaveformswouldbehelpfulindebuggingacircuit!DaleGroverPageshavebeenomittedDaleGroverPhysicalDimensionsinches(millimeters)unlessotherwisenoted(Continued)LIFESUPPORTPOLICYNATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDEVICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTANDGENERALCOUNSELOFNATIONALSEMICONDUCTORCORPORATIONAsusedherein:Lifesupportdevicesorsystemsaredevicesorsystemswhich,(a)areintendedforsurgicalimplantintothebody,or(b)supportorsustainlife,andwhosefailuretoperformwhenproperlyusedinaccordancewithinstructionsforuseprovidedinthelabeling,canbereasonablyexpectedtoresultinasignificantinjurytotheuserAcriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbereasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectivenessNationalSemiconductorCorporationAmericasTel:Fax:Email:supportnsccomNationalSemiconductorEuropeFax:()Email:europesupportnsccomDeutschTel:()EnglishTel:()FrançaisTel:()NationalSemiconductorAsiaPacificCustomerResponseGroupTel:Fax:Email:apsupportnsccomNationalSemiconductorJapanLtdTel:Fax:wwwnationalcomMoldedDualInLinePackage(N)NSPackageNumberNELMTimerNationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecificationsDaleGroverThepackageoutlinescanalsobeasourceforpinnumberingifyouareindoubtNotethatplasticDIPisthemostcommonpackageforprototypingAvoidsurfacemountpackages(eg,SOIC,MSOP,PQFP),thoughwiththepropersocketPLCCpackagescanbesolderedtorelativelyeasily(butnotusedinaplasticprototypeboardwithoutanadapter)Thereisgreatvariationinpricingdependingonpackagetype(andotherfactorssuchastemperaturerange,speed,etc),sobesuretodoublecheckpartnumbersDaleGroverFinally,rememberthatdatasheetscanalwaysbeinerrorButjustlikeprogramming,oferrorsareusererrorsIfyoufindwhatyouthinkisanerror,makesureyouhavethemostrecentdatasheet,andsendapolitequerytotheappropriatetechnicalsupportNewsgroupssuchasscielectronicsdesignmightbeusefultoqueryfirst

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教你如何看懂芯片资料(Datasheet)

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