ADS1256中文资料

SBAS288D−JUNE2003−REVISEDAUGUST2004
    FEATURES
24Bits,NoMissingCodes−AllDataRatesandPGASettings
Upto23BitsNoise-FreeResolution
±0.0010%Nonlinearity(max)
DataOutputRatesto30kSPS
FastChannelCycling−18.6BitsNoise-Free(21.3EffectiveBits)at1.45kHz
One-ShotConversionswithSingle-CycleSettling
FlexibleInputMultiplexerwithSensorDetect−FourDifferentialInputs(ADS1256only)−EightSingle-EndedInputs(ADS1256only)
Chopper-StabilizedInputBuffer
Low-NoisePGA:27nVInput-ReferredNoise
SelfandSystemCalibrationforAllPGASettings
5VTolerantSPI-CompatibleSerialInterface
AnalogSupply:5V
DigitalSupply:1.8Vto3.6V
PowerDissipation−AsLowas38mWinNormalMode−0.4mWinStandbyModeAPPLICATIONS
WeighScales
ScientificInstrumentation
IndustrialProcessControl
MedicalEquipment
TestandMeasurementDESCRIPTIONTheADS1255andADS1256areextremelylow-noise,24-bitanalog-to-digital(A/D)converters.Theyprovidecompletehigh-resolutionmeasurementsolutionsforthemostdemandingapplications.Theconverteriscomprisedofa4th-order,delta-sigma(∆Σ)modulatorfollowedbyaprogrammabledigitalfilter.Aflexibleinputmultiplexerhandlesdifferentialorsingle-endedsignalsandincludescircuitrytoverifytheintegrityoftheexternalsensorconnectedtotheinputs.Theselectableinputbuffergreatlyincreasestheinputimpedanceandthelow-noiseprogrammablegainamplifier(PGA)providesgainsfrom1to64inbinarysteps.Theprogrammablefilterallowstheusertooptimizebetweenaresolutionofupto23bitsnoise-freeandadatarateofupto30ksamplespersecond(SPS).Theconvertersofferfastchannelcyclingformeasuringmultiplexedinputsandcanalsoperformone-shotconversionsthatsettleinjustasinglecycle.CommunicationishandledoveranSPI-compatibleserialinterfacethatcanoperatewitha2-wireconnection.OnboardcalibrationsupportsbothselfandsystemcorrectionofoffsetandgainerrorsforallthePGAsettings.BidirectionaldigitalI/Osandaprogrammableclockoutputdriverareprovidedforgeneraluse.TheADS1255ispackagedinanSSOP-20,andtheADS1256inanSSOP-28.Alltrademarksarethepropertyoftheirrespectiveowners.!#$!# %&  '(%)(* ' +,+(''%&)' % ' )-&%#.$(&++,+(' )' +'  '(+ %)&,2003−2004,TexasInstrumentsIncorporatedPleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.XTAL2SerialInterfaceMuxandSensorDetectProgrammableDigitalFilter4th−OrderModulatorVREFPVREFNADS1256OnlyADS1256OnlyBufferAVDDDVDD1:64DGNDD3D2D1D0/CLKOUTAGNDAIN0AIN1AIN2AIN3AIN4AIN5AIN6AIN7AINCOMXTAL1/CLKINRESETDRDYSCLKDINSYNC/PDWNCSDOUTControlGeneralPurposeDigitalI/OClockGeneratorPGASBAS288D−JUNE2003−REVISEDAUGUST2004(1)PRODUCTPACKAGE-LEADPACKAGEDESIGNATORPACKAGEMARKINGORDERINGNUMBERTRANSPORTMEDIA,QUANTITYADS1255SSOP-20DBADS1255IDBADS1255IDBTTapeandReel,250ADS1255SSOP-20DBADS1255IDBADS1255IDBRTapeandReel,1000ADS1256SSOP-28DBADS1256IDBADS1256IDBTTapeandReel,250ADS1256SSOP-28DBADS1256IDBADS1256IDBRTapeandReel,1000(1)Forthemostcurrentpackageandorderinginformation,refertoourwebsiteat(1)ADS1255,ADS1256UNITAVDDtoAGND−0.3to+6VDVDDtoDGND−0.3to+3.6VAGNDtoDGND−0.3to+0.3VInputCurrent100,MomentarymAInputCurrent10,ContinuousmAAnaloginputstoAGND−0.3toAVDD+0.3VDigitalinputsDIN,SCLK,CS,RESET,SYNC/PDWN,XTAL1/CLKINtoDGND−0.3to+6VinputsD0/CLKOUT,D1,D2,D3toDGND−0.3toDVDD+0.3VMaximumJunctionTemperature+150°COperatingTemperatureRange−40to+105°CStorageTemperatureRange−60to+150°CLeadTemperature(soldering,10s)+300°C(1)StressesabovethoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Exposuretoabsolutemaximumconditionsforextendedperiodsmaydegradedevicereliability.Thesearestressratingsonly,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthosespecifiedisnotimplied.ThisintegratedcircuitcanbedamagedbyESD.TexasInstrumentsrecommendsthatallintegratedcircuitsbehandledwithappropriateprecautions.Failuretoobserveproperhandlingandinstallationprocedurescancausedamage.ESDdamagecanrangefromsubtleperformancedegradationtocompletedevicefailure.Precisionintegratedcircuitsmaybemoresusceptibletodamagebecauseverysmallparametricchangescouldcausethedevicenottomeetitspublishedspecifications.SBAS288D−JUNE2003−REVISEDAUGUST2004−40°Cto+85°C,AVDD=+5V,DVDD=+1.8V,fCLKIN=7.68MHz,PGA=1,andVREF=+2.5V,unlessotherwisenoted.PARAMETERTESTCONDITIONSMINTYPMAXUNITAnalogInputsFull-scaleinputvoltage(AINP−AINN)±2VREF/PGAVAbsoluteinputvoltage(AIN0-7,AINCOMtoAGND)BufferoffAGND−0.1AVDD+0.1VAbsoluteinputvoltage(AIN0-7,AINCOMtoAGND)BufferonAGNDAVDD−2.0VProgrammablegainamplifier164Bufferoff,PGA=1,2,4,8,16150/PGAkΩDifferentialinputimpedanceBufferoff,PGA=32,644.7kΩDifferentialinputimpedanceBufferon,fDATA≤50Hz(1)80MΩSDCS[1:0]=010.5µASensordetectcurrentsour