ADS8638
ZHCS362A–MAY2011–REVISEDAUGUST2011
具有软件可选范围的12位、1MSPS、4/8通道、双极输入、SAR模数转换器
查询样品:ADS8634,ADS8638
1特性
•23可选输入范围：±10V、±5V、±2.5V、0V至10V，或0V至5V高达±12V，具有外部基准
•速率高达1MSPS的无延迟转换
•出色的性能：12位无漏失码INL：±0.9LSBSNR：71.8dB
•高度集成：4通道或8通道输入多路复用器温度传感器内部电压基准用于每个通道的报警门限
•低功耗：14.45mW（在1MSPS时）5.85mW（在0.1MSPS时）灵活的断电模式
•SPI™兼容型串行接口
•扩展温度范围：–40°C至+125°
C •小占位面积：4mm×4mmQFN封装 说明 ADS8634andADS8638(ADS8634/8)是12位的模数转换器（ADCs）,他们能够在1MSPS下测量达到±10V的输入电压。
使用逐次求近寄存器(SAR)核心，这些模数转换器可以提供一个采样保持前端的无延迟转换。
ADS8634包括一个输入复用器(mux)来测量最多四位的输入。
ADS8638可以测量最多八位的输入。
除了输入复用器，ADS8634/8特别装有内部温度传感器、电压基准和一个数字比较器以为每个输入设定报警阀值；因此，最少数量的外部部件是必需的。
一个简单的SPI兼容接口提供了通信和控制。
数字电源可一直工作在5伏电压或下至1.8伏电压以便与多种多样的处理器和控制器进行直接连接。
对于那些要求严格的测量仪器，ADS8634/8可以在工业温度–40°C到+125°C下工作并有小规格的QFN-24封装。
应用 •可编程逻辑控制器•数据采集系统•高速、闭合回路系统•数字电源 AIN0AIN1AIN2AIN3 HVDDMUX AVDDREF REF DVDD AlarmThreshold Comparator ADCSPI AINGND TempSensor HVSS ADS8634 AGND REFGND DGND HVDD AL_PD CS,SCLK,DIN,DOUT AIN0AIN1AIN2AIN3AIN4AIN5AIN6AIN7 AINGND TempSensor MUXHVSS AVDDREF REF DVDD AlarmThreshold Comparator ADCSPI ADS8638 AGND REFGND DGND AL_PD CS,SCLK,DIN,DOUT
1 Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.2SPIisatrademarkofMotorola.3Allothertrademarksarethepropertyoftheirrespectiveowners. PRODUCTIONDATAinformationiscurrentasofpublicationdate.ProductsconformtospecificationsperthetermsoftheTexasInstrumentsstandardwarranty.Productionprocessingdoesnotnecessarilyincludetestingofallparameters. Copyright©2011,TexasInstrumentsIncorporatedEnglishDataSheet:SBAS541A ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ThisintegratedcircuitcanbedamagedbyESD.TexasInstrumentsmendsthatallintegratedcircuitsbehandledwithappropriateprecautions.Failuretoobserveproperhandlingandinstallationprocedurescancausedamage. ESDdamagecanrangefromsubtleperformancedegradationpletedevicefailure.Precisionintegratedcircuitsmaybemoresusceptibletodamagebecauseverysmallparametricchangescouldcausethedevicenottomeetitspublishedspecifications. PRODUCTADS8634ADS8638 DEVICECOMPARISON
(1) RESOLUTION CHANNELS 412-Bit
8 SAMPLERATE1MSPS
(1)Forthemostcurrentpackageandorderinginformation,seethePackageOptionAddendumattheendofthisdocument,orvisitthedeviceproductfolderat. ABSOLUTEMAXIMUMRATINGS Overoperatingfree-airtemperaturerange,unlessotherwisenoted.
(1) AINntoAGNDorAINGNDtoAGND AVDDtoAGNDorDVDDtoDGND HVDDtoAGND HVSStoAGND HVDDtoHVSS DigitalinputvoltagetoDGND DigitaloutputtoDGND Operatingtemperaturerange Storagetemperaturerange ESDratings,allpins Humanbodymodel(HBM)Chargeddevicemodel(CDM) VALUEHVSS–0.3toHVDD+0.3 –0.3to7–0.3to18–18to0.3–0.3to33–0.3toDVDD+0.3–0.3toDVDD+0.3–40to+125–65to+150 ±2000±500 UNITVVVVVVV°C°CVV
(1)Stressesbeyondthoselistedunderabsolutemaximumratingsmaycausepermanentdamagetothedevice.Thesearestressratingsonly,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedundermendedoperatingconditionsisnotimplied.Exposuretoabsolute–maximum–ratedconditionsforextendedperiodsmayaffectdevicereliability.ThesearestressratingsonlyandfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthosespecifiedintheElectricalCharacteristicstableisnotimplied.
2 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ELECTRICALCHARACTERISTICS:ADS8634,ADS8638 Minimum/maximumspecificationsatTA=–40°Cto+125°C,fSAMPLE=1MSPS,HVDD=10Vto15V,HVSS=–10Vto–15V,AVDD=4.75Vto5.25V,DVDD=2.7Vto3.6V,andVREF=2.5V,unlessotherwisenoted.Typicalspecificationsat+25°C,fSAMPLE=1MHz,HVDD=10V,HVSS=–10V,AVDD=3.3V,DVDD=3.3V,andVREF=2.5V,unlessotherwisenoted. ADS8634,ADS8638 PARAMETER TESTCONDITIONS MIN TYP MAXUNIT ANALOGINPUT ±2.5
V Full-scaleinputspan
(1) Bipolarranges,VREF=2.5V ±
5 V ±10
V Unipolarranges,VREF=2.5V 0to5
V 0to10
V AINxabsoluteinputrange HVSS HVDD
V AINGNDabsoluteinputrange –0.2 0.2
V Inputcapacitance
8 pF Inputleakagecurrent At+125°
C 200 nA SYSTEMPERFORMANCE Resolution 12 Bits Nomissingcodes 12 Bits Integrallinearity –1.5+0.9/–0.9 1.5LSB
(2) Differentiallinearity –1.0+0.9/–0.5 1.6LSB Offseterror
(3) –
3 ±0.8 3LSB Offseterrordrift 0.75 ppmFS/°C( 4) Gainerror
(5)GainerrordriftNoise Power-supplyrejection Crosstalk Isolationcrosstalk Memorycrosstalk SAMPLINGDYNAMICSConversiontimeAcquisitiontimeMaximumthroughputrateAperturedelayStepresponse AtFFChoutputcodewith250mVPPand480HzrippleonAVDDCrosstalkonchannel0withchannel0permanentlyselected,2kHzfull-scalesinewaveonchannel1,allotherchannelsgroundedCrosstalkonchannel0,2kHzfull-scalesinewaveonchannel1,allotherchannelsgrounded,devicescanschannel0andchannel1alternately At20MHzSCLK,DVDD=2.7Vto5.25VAVDD=2.7Vto5.25VAt20MHzSCLK,DVDD=2.7Vto5.25V –
8 ±
2 1.2 0.33 –87 –110 –81 2501 13250 8LSBppm/°CLSBdB dB dB 750 ns ns 1MSPS ns ns
(1)Idealinputspan;doesnotincludegainoroffseterror.
(2)LSBmeansleastsignificantbit.
(3)Measuredrelativetoanidealfull-scaleinput.(4)ppmFS/°Cisdriftmeasuredinpartspermillionoffull-scalerangeperdegreecentigrade.
(5)Doesnotincludereferencedrift. Copyright©2011,TexasInstrumentsIncorporated
3 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ELECTRICALCHARACTERISTICS:ADS8634,ADS8638(continued) Minimum/maximumspecificationsatTA=–40°Cto+125°C,fSAMPLE=1MSPS,HVDD=10Vto15V,HVSS=–10Vto–15V,AVDD=4.75Vto5.25V,DVDD=2.7Vto3.6V,andVREF=2.5V,unlessotherwisenoted.Typicalspecificationsat+25°C,fSAMPLE=1MHz,HVDD=10V,HVSS=–10V,AVDD=3.3V,DVDD=3.3V,andVREF=2.5V,unlessotherwisenoted. ADS8634,ADS8638 PARAMETER TESTCONDITIONS MIN TYP MAXUNIT DYNAMICCHARACTERISTICS Totalharmonicdistortion
(6)(THD) At1kHzAt100kHz –81 dB –80 dB Signal-to-noiseratio(SNR) At1kHzAt100kHz 71 71.8 dB 71.1 dB Signal-to-noiseanddistortionratio(SINAD) At1kHzAt100kHz 70.1 71.3 dB 70.5 dB Spurious-freedynamicrange(SFDR) At1kHzAt100kHz –83 dB –80 dB Full-powerbandwidth At–3dB
1 MHz DIGITALINPUT/OUTPUT Logicfamily CMOS
V VIH 0.7DVDD
V VILLogiclevel VOH With20pFloadonSDO 0.8DVDD 0.3DVDD
V V VOL With20pFloadonSDO 0.2DVDD
V EXTERNALVOLTAGEREFERENCE Referenceinputvoltagerange VREF 3.0or 2.0 AVDD,
V whichever isless INTERNALVOLTAGEREFERENCE Referenceoutputvoltage 2.5
V Initialuracy –1.2 1.2 % TemperaturedriftDrivecurrent,source
(7) 20 ppm/°
C 750 µ
A Drivecurrent,sink 20 µ
A Driveroutputimpedance
1 Ω Turn-onsettlingtime With10µFdecouplingcapacitorfromREFtoREFGND
9 ms INTERNALTEMPERATURESENSOR Absoluteuracy
5 %ofFSR
(6)Calculatedonthefirstnineharmonicsoftheinputfrequency.
(7)Internalreferenceoutputisshort-circuitprotected.Incaseofshort-circuittoground,thedrivecurrentislimitedtothisvalue.
4 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ELECTRICALCHARACTERISTICS:ADS8634,ADS8638(continued) Minimum/maximumspecificationsatTA=–40°Cto+125°C,fSAMPLE=1MSPS,HVDD=10Vto15V,HVSS=–10Vto–15V,AVDD=4.75Vto5.25V,DVDD=2.7Vto3.6V,andVREF=2.5V,unlessotherwisenoted.Typicalspecificationsat+25°C,fSAMPLE=1MHz,HVDD=10V,HVSS=–10V,AVDD=3.3V,DVDD=3.3V,andVREF=2.5V,unlessotherwisenoted. ADS8634,ADS8638 PARAMETER TESTCONDITIONS MIN TYP MAXUNIT POWER-SUPPLYREQUIREMENTS VAVDD 2.7 3.3 5.25
V Supplyvoltage VDVDDVHVDD 10VV
5
10
15
V VHVSS 10V0
V
IAVDD(dynamic)
AtVAVDD=2.7Vto3.6Vand1MHzthroughput,normalmodewithinternalreferenceandtemperaturesensoroff
AtVAVDD=4.75Vto5.25Vand1MHzthroughput,normalmodewithinternalreferenceandtemperaturesensoroff
2.5
mA
3.1
3.6
mA
AVDDsupplycurrent
IAVDD(static)
AtVAVDD=2.7Vto3.6VandSCLKoff,normalmodewithinternalreferenceandtemperaturesensoroff
AtVAVDD=4.75Vto5.25VandSCLKoff,normalmodewithinternalreferenceandtemperaturesensoroff
1.45
mA
1.5
1.9
mA
IAVDD(ref)
(8) AtVAVDD=2.7Vto5.25V,additionalAVDDcurrentwithinternalreferenceonandtemperaturesensoroff 180 µ
A IAVDD(temp)
(9) AtVAVDD=2.7Vto5.25V,additionalAVDDcurrentwithinternaltemperaturesensoronandinternalreferenceoff 400 µ
A HVDDsupplycurrent IHVDD(dynamic)IHVDD(static) HVDD=15Vand1MSPSthroughputHVDD=15VanddevicestaticwithSCLKoff 270 350 µ
A 5 µ
A HVSSsupplycurrent IHVSS(dynamic)IHVSS(static) HVSS=–15Vand1MSPSthroughputHVSS=–15VanddevicestaticwithSCLKoff 520 µ
A 5 µ
A DVDDsupplycurrent(10) IDVDD DVDD=3.3V,fSAMPLE=1MSPS,DOUTload=20pF 2.5 mA Power-downstate AVDDcurrentHVDDcurrent SCLKoff,internalreferenceandtemperaturesensoroffSCLKon,internalreferenceandtemperaturesensoroff 10 µ
A 160 µ
A 5 µ
A HVSScurrent
5 µ
A TEMPERATURERANGE Specifiedperformance –40 +125 °
C
(8)AddIAVDD(ref)toIAVDD(dynamic)orIAVDD(static)(asapplicable),ifinternalreferenceisselected.
(9)AddIAVDD(temp)toIAVDD(dynamic)orIAVDD(static)(asapplicable),ifinternaltemperaturesensorisenabled.(10)IDVDDconsumesonlydynamiccurrent.IDVDD=CLOAD×VDVDD×numberof0→1transitionsinDOUT×fSAMPLE.IDVDDisa load-dependentcurrent;thereisnocurrentwhentheoutputisnottoggling. THERMALINFORMATION THERMALMETRIC
(1) θJAθθJBψJTψJBθJCbot Junction-to-ambientthermalresistanceJunction-to-case)thermalresistanceJunction-to-boardthermalresistancecharacterizationparameterJunction-to-boardcharacterizationparameterJunction-to-case(bottom)thermalresistance
(1)有关传统和新的热度量的更多信息，请参阅IC封装热度量应用报告SPRA953。
ADS8634/8RGERGE 24PINS32.630.53.30.49.32.6 UNITS°C/W Copyright©2011,TexasInstrumentsIncorporated
5 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 PARAMETERMEASUREMENTINFORMATION TIMINGDIAGRAM tsu(CS-SCLK)CS 1/fSAMPLE SCLK DOUT td(CS-DO) DIN 1R1F2
3 th(SCLK-DOUT)
4 5 td(SCLK-DOUT) tsu(DIN-SCLK) 12th(SCLK-DIN) 13 14 tw(SCLK_H) 15 16R16F tw(SCLK_L) td(CS-DOHZ) Acquisition(Internal) tc Table1.TimingRequirements
(1)(2)
(3) PARAMETER tc Conversiontime t(ACQ) Acquisitiontime td(CS-DO) Delaytime,CSlowtofirstdata(D0toD15)out tsu(CS-SCLK)Setuptime,CSlowtofirstSCLKrisingedge td(SCLK-DOUT)Delaytime,SCLKfallingtoDOUT th(SCLK-DOUT)Holdtime,SCLKfallingtoDOUTvalid td(CS-DOHZ)DelaytimeCShightoDOUThigh-z TESTCONDITIONSDVDD=1.8V DVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5V ADS8634,ADS8638 MIN TYP 250250250 26.018.515.5 5.55.04.77.36.45.9 t(ACQ) MAX151515 52.540.030.5 51.533.025.3 31.022.016.4 UNITSCLKSCLKSCLK nsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsns
(1)Allspecificationsat–40°Cto+125°C,unlessotherwisenoted.(2)1.8Vspecificationsapplyfrom1.65Vto1.95V;3Vspecificationsapplyfrom2.7Vto3.6V;and5Vspecificationsapplyfrom4.75Vto 5.25V.
(3)With20pFloadonDOUT.
6 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 tsu(DIN-SCLK)th(SCLK-DIN)tW(SCLK_H)tW(SCLK_L)fSCLKfSAMPLE PARAMETERMEASUREMENTINFORMATION(continued)Table1.TimingRequirements
(1)(2)
(3)(continued) PARAMETERSetuptime,DINvalidtoSCLKrisingedgeHoldtime,SCLKrisingtoDINvalidPulseduration,SCLKhighPulseduration,SCLKlowSCLKfrequencySamplingfrequency TESTCONDITIONSDVDD=1.8V DVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5V ADS8634,ADS8638 MIN TYP 7.0 6.0 5.0 9.0 8.0 7.0 25 20 20 25 20 20 MAX 1620200.84 11 UNITnsnsnsnsnsnsnsnsnsnsnsnsMHzMHzMHz MSPSMSPSMSPS POWER-UPTIMINGREQUIREMENTS CSSCLK 1216 1216 1216 1216 AL_PDProgrammedasPD Power-DownState(Internal) Power-Down Td(PWRUP)Power-UpDelay Active DOUT InvalidData InvalidData InvalidData ValidData ValidData Table2.TIMINGREQUIREMENTS
(1) td(PWRUP)
(2) PARAMETERPower-updelayfromfirstCSaftermandInvalidconversionsafterdeviceisactive(poweredup) ADS8634,ADS8638 MIN TYP
(1)Allspecificationsat–40°Cto+125°C,unlessotherwisenoted.
(2)Power-uptimeexcludesinternalreferenceandtemperaturesensor. MAX11 UNITµs Conversion Copyright©2011,TexasInstrumentsIncorporated
7 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 PINCONFIGURATIONS RGEPACKAGE4mm×4mmQFN-24 (TOPVIEW) 24REF23REFGND22AL_PD21DVDD20DGND19DOUT AVDD1AGND2AGND3 NC4AINGND5 NC6 ThermalPad(BottomSide) 18DIN17SCLK16CS15HVSS14HVDD13NC NC7AIN38AIN29AIN110AIN011 NC12 PINNUMBER1 2,34,6,7,12,13 58910111415161718192021 22 23 24 Figure1.ADS8634PinConfiguration NAMEAVDDAGND NCAINGND AIN3AIN2AIN1AIN0HVDDHVSSCSSCLKDINDOUTDGNDDVDD AL_PD REFGND REF ADS8634PINASSIGNMENTS FUNCTION DESCRIPTION AnalogpowersupplyAnalogpowersupply AnalogpowersupplyAnalogground — Thesepinsarenotinternallyconnected;donotfloatthesepins. ItismendedtoconnectthesepinstoAGND. Input Commonforallanaloginputchannels;actsasgroundsenseterminal Analoginput Analoginputchannel3 Analoginput Analoginputchannel2 Analoginput Analoginputchannel1 Analoginput Analoginputchannel0 High-voltagepowersupplyHigh-voltagepositivesupplyformultiplexerchannels High-voltagepowersupplyHigh-voltagenegativesupplyformultiplexerchannels Digitalinput Chipselectinput Digitalinput Serialclockinput Digitalinput Serialdatainput Digitaloutput Serialdataoutput DigitalpowersupplyDigitalground DigitalpowersupplyDigitalI/Osupply Digitaloutput Activehigh,outputindicatesalarm(programmedasanoutputpin) Digitalinput Activelow,asynchronouspower-down.Thedevicefeaturesaninternal,weakpull-upresistorfromtheAL_PDpintoDVDD.TheAL_PDpincanalsobefloatedwhenprogrammedasapower-downinput.(Thedefaultconditionforthispinisprogrammedasapower-downinputpin.) Analoginput Referencegroundinputtodevicewhenanexternalreferenceisselected.Thispinactsasareferencedecouplinggroundterminalwhenaninternalreferenceisselected. Analoginput Referenceinputtodevicewhenanexternalreferenceisselected.Thispinactsasareferencedecouplingterminalwhenaninternalreferenceisselected.
8 Copyright©2011,TexasInstrumentsIncorporated RGEPACKAGE4mm×4mmQFN-24 (TOPVIEW) ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 24REF23REFGND22AL_PD21DVDD20DGND19DOUT AVDD1AGND2AGND3 NC4AINGND5 AIN76 ThermalPad(BottomSide) 18DIN17SCLK16CS15HVSS14HVDD13AIN0 AIN67AIN58AIN49AIN310AIN211AIN112 Figure2.ADS8638PinConfiguration PINNUMBER1 2,3456789101112131415161718192021 22 23 24 NAMEAVDDAGND NCAINGND AIN7AIN6AIN5AIN4AIN3AIN2AIN1AIN0HVDDHVSSCSSCLKDINDOUTDGNDDVDD AL_PD REFGND REF ADS8638PINASSIGNMENTS FUNCTION DESCRIPTION AnalogpowersupplyAnalogpowersupply AnalogpowersupplyAnalogground — Thispinisnotinternallyconnected;donotfloatthispin. ItismendedtoconnectthispintoAGND. Input Commonforallanaloginputchannels;actsasgroundsenseterminal Analoginput Analoginputchannel7 Analoginput Analoginputchannel6 Analoginput Analoginputchannel5 Analoginput Analoginputchannel4 Analoginput Analoginputchannel3 Analoginput Analoginputchannel2 Analoginput Analoginputchannel1 Analoginput Analoginputchannel0 High-voltagepowersupplyHigh-voltagepositivesupplyformultiplexerchannels High-voltagepowersupplyHigh-voltagenegativesupplyformultiplexerchannels Digitalinput Chipselectinput Digitalinput Serialclockinput Digitalinput Serialdatainput Digitaloutput Serialdataoutput DigitalpowersupplyDigitalground DigitalpowersupplyDigitalI/Osupply Digitaloutput Activehigh,outputindicatingalarm(programmedasanoutputpin) Digitalinput Activelow,asynchronouspower-down(programmedasaninputpin,defaultcondition) Analoginput Referencegroundinputtodevicewhenanexternalreferenceisselected.Thispinactsasreferencedecouplinggroundterminalwhenaninternalreferenceisselected. Analoginput Referenceinputtodevicewhenanexternalreferenceisselected.Thispinactsasreferencedecouplingterminalwhenaninternalreferenceisselected. Copyright©2011,TexasInstrumentsIncorporated
9 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. DifferentialNonlinearity(LSB) DNLvsANALOGSUPPLYVOLTAGE 1.6 1.4 1.2 MaximumDNL
1 0.8 0.6 0.4 0.2
0 −0.2 MinimumDNL −0.4 −0.6 −0.8 −
1 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G013 Figure3. DifferentialNonlinearity(LSB) 1.61.41.2 10.80.60.40.2 0−0.2−0.4−0.6−0.8 −1±2.5V DNLvsSIGNALRANGE MaximumDNL MinimumDNL ±5V ±10V 0−5V SignalRange Figure4. 0−10V G014 DifferentialNonlinearity(LSB) 1.61.41.2 10.80.60.40.2 0−0.2−0.4−0.6−0.8 −12 DNLvsREFERENCEVOLTAGE MaximumDNL MinimumDNL 2.2 2.4 2.6 2.8
3 ReferenceVoltage(V)G015 Figure5. DifferentialNonlinearity(LSB) DNLvsCHANNELNUMBER 1.6 1.4 1.2 MaximumDNL
1 0.8 0.6 0.4 0.2
0 −0.2 MinimumDNL −0.4 −0.6 −0.8 −
1 0
1 2
3 4
5 6
7 ChannelNumberG016 Figure6. DifferentialNonlinearity(LSB) 1.61.41.2 10.80.60.40.2 0−0.2−0.4−0.6−0.8 −1−40 DNLvsFREE-AIRTEMPERATURE MaximumDNL MinimumDNL−25−105203550658095 Free-AirTemperature(°C) Figure7. 110125 G017 DifferentialNonlinearity(LSB) DNLvsPOSITIVEHIGH-VOLTAGESUPPLY 1.6 1.4 MaximumDNL 1.2
1 0.8 0.6 0.4 0.2
0 −0.2 MinimumDNL −0.4 −0.6 −0.8 −
1 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G018 Figure8. 10 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. INLvsANALOGSUPPLYVOLTAGE INLvsSIGNALRANGE 1.5 1.5 1.2 MaximumINL 0.9 1.2 MaximumINL 0.9 IntegralNonlinearity(LSB) IntegralNonlinearity(LSB) 0.6 0.6 0.3 0.3 0MinimumINL −0.3 0−0.3MinimumINL −0.6 −0.6 −0.9 −0.9 −1.2 −1.2 −1.5 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G019 −1.5±2.5V ±5V ±10V 0−5V SignalRange 0−10V G020 Figure9. Figure10. IntegralNonlinearity(LSB) 1.51.20.90.60.3 0−0.3−0.6−0.9−1.2−1.5
2 INLvsREFERENCEVOLTAGE MaximumINL MinimumINL 2.2 2.4 2.6 2.8
3 ReferenceVoltage(V)G021 Figure11. IntegralNonlinearity(LSB) INLvsCHANNELNUMBER 1.5 1.2 MaximumINL 0.9 0.6 0.3
0 −0.3 MinimumINL −0.6 −0.9 −1.2 −1.5
0 1
2 3
4 5
6 7 ChannelNumberG022 Figure12. IntegralNonlinearity(LSB) INLvsFREE-AIRTEMPERATURE 1.5 1.2 MaximumINL 0.9 0.6 0.3 0−0.3MinimumINL −0.6 −0.9 −1.2 −1.5−40−25−105203550658095Free-AirTemperature(°C) Figure13. 110125 G023 IntegralNonlinearity(LSB) INLvsPOSITIVEHIGH-VOLTAGESUPPLY 1.5 1.2 MaximumINL 0.9 0.6 0.3
0 −0.3 MinimumINL −0.6 −0.9 −1.2 −1.5 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G024 Figure14. Copyright©2011,TexasInstrumentsIncorporated 11 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. OFFSETERRORvsANALOGSUPPLYVOLTAGE OFFSETERRORvsSIGNALRANGE 2.5 2.5
2 2 1.5 1.5 OffsetError(LSB) OffsetError(LSB)
1 1 0.5 0.5
0 0 −0.5 −0.5 −
1 −
1 −1.5 −1.5 −
2 −
2 −2.5 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD
(V)G025 −2.5±2.5V ±5V ±10V 0−5V SignalRange 0−10V G026 Figure15. Figure16. OffsetError(LSB) OFFSETERRORvsREFERENCEVOLTAGE 2.5
2 1.5
1 0.5
0 −0.5 −
1 −1.5 −
2 −2.5
2 2.2 2.4 2.6 2.8
3 Reference
Voltage(V)G027 Figure17. OffsetError(LSB) OFFSETERRORvsCHANNELNUMBER 2.5
2 1.5
1 0.5
0 −0.5 −
1 −1.5 −
2 −2.5
0 1
2 3
4 5
6 7 ChannelNumberG028 Figure18. OffsetError(LSB) OFFSETERRORvsFREE-AIRTEMPERATURE 2.5
2 1.5
1 0.5
0 −0.5 −
1 −1.5 −
2 −2.5−40−25−10 52035506580Free-AirTemperature(°C) 95110125 G029 Figure19. OffsetError(LSB) OFFSETERRORvsPOSITIVEHIGH-VOLTAGESUPPLY 2.5
2 1.5
1 0.5
0 −0.5 −
1 −1.5 −
2 −2.5 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G030 Figure20. 12 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. GAINERRORvsANALOGSUPPLYVOLTAGE GAINERRORvsSIGNALRANGE
8 8
6 6
4 4 GainError(LSB) GainError(LSB)
2 2
0 0 −
2 −
2 −
4 −
4 −
6 −
6 −
8 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G031 Figure21. −8±2.5V ±5V ±10V SignalRange Figure22. 0−5V 0−10V G032 GainError(LSB) GAINERRORvsREFERENCEVOLTAGE
8 6
4 2
0 −
2 −
4 −
6 −
8 2 2.2 2.4 2.6 2.8
3 ReferenceVoltage(V)G033 Figure23. GainError(LSB) GAINERRORvsCHANNELNUMBER
8 6
4 2
0 −
2 −
4 −
6 −
8 0
1 2
3 4
5 6
7 ChannelNumberG034 Figure24. GainError(LSB) GAINERRORvsFREE-AIRTEMPERATURE
8 6
4 2
0 −
2 −
4 −
6 −8−40−25−10 52035506580Free-AirTemperature(°C) Figure25. 95110125 G035 GainError(LSB) GAINERRORvsPOSITIVEHIGH-VOLTAGESUPPLY
8 6
4 2
0 −
2 −
4 −
6 −
8 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G036 Figure26. Copyright©2011,TexasInstrumentsIncorporated 13 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. SNRvsANALOGSUPPLYVOLTAGE SNRvsSIGNALRANGE 72 72 71.8 71.8 Signal-to-NoiseRatio(dB) Signal-to-NoiseRatio(dB) 71.6 71.6 71.4 71.4 71.2 71.2 71 71 70.8 70.8 70.6 70.6 70.4 70.4 70.2 70.2 70 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD
(V)G037 70±2.5V ±5V ±10V 0−5V SignalRange 0−10V G038 Figure27. Figure28. Signal-to-NoiseRatio(dB) SNRvsREFERENCEVOLTAGE 72 71.8 71.6 71.4 71.2 71 70.8 70.6 70.4 70.2 70
2 2.2 2.4 2.6 2.8
3 Reference
Voltage(V)G039 Figure29. Signal-to-NoiseRatio(dB) SNRvsCHANNELNUMBER 72 71.8 71.6 71.4 71.2 71 70.8 70.6 70.4 70.2 70
0 1
2 3
4 5
6 7 Channel
NumberG040 Figure30. Signal-to-NoiseRatio(dB) SNRvsFREE-AIRTEMPERATURE 7271.871.671.471.2 7170.870.670.470.2 70−40−25−105203550658095Free-AirTemperature(°C) Figure31. 110125 G041 Signal-to-NoiseRatio(dB) SNRvsPOSITIVEHIGH-VOLTAGESUPPLY 72 71.8 71.6 71.4 71.2 71 70.8 70.6 70.4 70.2 70 2.5
5 7.5 10 12.5 15 HVDD,
PositiveHigh-VoltageSupply(V)G042 Figure32. 14 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. SNRvsINPUTFREQUENCY SINADvsANALOGSUPPLYVOLTAGE 72 72 Signal-to-NoiseandDistortion(dB) 71.8 71.8 Signal-to-NoiseRatio(dB) 71.6 71.6 71.4 71.4 71.2 71.2 71 71 70.8 70.8 70.6 70.6 70.4 70.4 70.2 70.2 70
0 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G043 70 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G044 Figure33. Figure34. Signal-to-NoiseandDistortion(dB) 7271.871.671.471.2 7170.870.670.470.2 70±2.5V SINADvsSIGNALRANGE ±5V ±10V SignalRange Figure35. 0−5V 0−10V G045 Signal-to-NoiseandDistortion(dB) SINADvsREFERENCEVOLTAGE 72 71.5 71 70.5 70 69.5 69 68.5 68
2 2.2 2.4 2.6 2.8
3 ReferenceVoltage(V)G046 Figure36. Signal-to-NoiseandDistortion(dB) SINADvsCHANNELNUMBER 72 71.5 71 70.5 70 69.5 69 68.5 68
0 1
2 3
4 5
6 7 ChannelNumberG047 Figure37. Signal-to-NoiseandDistortion(dB) SINADvsFREE-AIRTEMPERATURE 72 71.5 71 70.5 70 69.5 69 68.5 68−40−25−10 52035506580Free-AirTemperature(dB) Figure38. 95110125 G048 Copyright©2011,TexasInstrumentsIncorporated 15 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. SINADvsPOSITIVEHIGH-VOLTAGESUPPLY SINADvsINPUTFREQUENCY 72 72 Signal-to-NoiseandDistortion(dB) Signal-to-NoiseandDistortion(dB) 71.5 71.5 71 71 70.5 70.5 70 70 69.5 69.5 69 69 68.5 68.5 68 2.5
5 7.5 10 12.5 15 HVDD,
PositiveHigh-VoltageSupply(V)G049 Figure39. 680 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G050 Figure40. TotalHarmonicDistortion(dB) THDvsANALOGSUPPLYVOLTAGE −82 −82.5 −83 −83.5 −84 −84.5 −85 −85.5 −86 −86.5 −87 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD
(V)G051 Figure41. TotalHarmonicDistortion(dB) −75−76−77−78−79−80−81−82−83−84−85−86−87 ±2.5V THDvsSIGNALRANGE ±5V ±10V SignalRange Figure42. 0−5V 0−10V G052 TotalHarmonicDistortion(dB) THDvsREFERENCEVOLTAGE −75 −76 −77 −78 −79 −80 −81 −82 −83 −84 −85 −86 −87
2 2.2 2.4 2.6 2.8
3 Reference
Voltage(V)G053 Figure43. TotalHarmonicDistortion(dB) THDvsCHANNELNUMBER −75 −76 −77 −78 −79 −80 −81 −82 −83 −84 −85 −86 −87
0 1
2 3
4 5
6 7 Channel
NumberG054 Figure44. 16 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. THDvsFREE-AIRTEMPERATURE THDvsPOSITIVEHIGH-VOLTAGESUPPLY −75 −75 −76 TotalHarmonicDistortion(dB) TotalHarmonicDistortion(dB) −77 −77 −78 −79 −79 −80 −81 −81 −82 −83 −83 −84 −85 −85 −86 −87−40−25−10 52035506580Free-AirTemperature(°C) 95110125 G055 −87 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G056 Figure45. Figure46. TotalHarmonicDistortion(dB) −75−76−77−78−79−80−81−82−83−84−85−86−87
0 THDvsINPUTFREQUENCY 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G057 Figure47. Spurious-FreeDynamicRange(dB) SFDRvsANALOGSUPPLYVOLTAGE 88 87.5 87 86.5 86 85.5 85 84.5 84 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD
(V)G058 Figure48. Spurious-FreeDynamicRange(dB) 8887.5 8786.5 8685.5 8584.5 8483.5 8382.5 82±2.5V SFDRvsSIGNALRANGE ±5V ±10V SignalRange Figure49. 0−5V 0−10V G059 Spurious-FreeDynamicRange(dB) SFDRvsREFERENCEVOLTAGE 88 87.5 87 86.5 86 85.5 85 84.5 84 83.5 83 82.5 82
2 2.2 2.4 2.6 2.8
3 Reference
Voltage(V)G060 Figure50. Copyright©2011,TexasInstrumentsIncorporated 17 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. SFDRvsCHANNELNUMBER SFDRvsFREE-AIRTEMPERATURE 88 88 Spurious-FreeDynamicRange(dB) Spurious-FreeDynamicRange(dB) 87.587 8786 86.5 86 85 85.584 8583 84.5 84
0 1
2 3
4 5
6 7 ChannelNumberG061 Figure51. 82−40−25−10 52035506580Free-AirTemperature(°C) Figure52. 95110125 G062 SFDRvsPOSITIVEHIGH-VOLTAGESUPPLY 88 SFDRvsINPUTFREQUENCY 90 Spurious-FreeDynamicRange(dB) Spurious-FreeDynamicRange(dB) 87 89 86 88 85 87 84 86 83 85 82 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G063 Figure53. 840 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G064 Figure54. CROSSTALKvsINPUTFREQUENCY −70 ANALOGSUPPLYCURRENT(Dynamic)vsANALOGSUPPLYVOLTAGE 3.5 −80 MemoryCrosstalk
3 AVDDDynamicCurrent(mA) Crosstalk(dB) −90 2.5 IsolationCrosstalk −100
2 −110−120
0 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G065 Figure55. 1.5 HVDD=15V HVSS=−15V
1 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G001 Figure56. 18 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. ANALOGSUPPLYCURRENT(Dynamic)vsFREE-AIRTEMPERATURE ANALOGSUPPLYCURRENT(Dynamic)vsSAMPLERATE 2.4HVDD=15VHVSS=−15V 3.5HVDD=15V 3HVSS=−15V 2.352.5 AVDDDynamicCurrent(mA) AVDDDynamicCurrent(mA) 22.3 1.5 2.2510.5 2.2−40−25−10 52035506580Free-AirTemperature(°C) Figure57. 95110125 G002
0 0 0.2 0.4 0.6 0.8
1 fSAMPLE,SampleRate(MSPS) G003 Figure58. ANALOGSUPPLYCURRENT(Static)vsANALOGSUPPLYVOLTAGE 1.8HVDD=15VHVSS=−15V 1.6 POSITIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsANALOGSUPPLYVOLTAGE 0.5 0.45 0.4 HVDDDynamicCurrent(mA) AVDDStaticCurrent(mA) 1.4 0.35 0.31.2 0.25
1 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G004 Figure59. 0.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G005 Figure60. HVDDDynamicCurrent(mA) POSITIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsFREE-AIRTEMPERATURE 0.5HVDD=15V 0.45HVSS=−15V 0.4 0.35 0.3 0.25 HVDDDynamicCurrent(mA) POSITIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsPOSITIVEHIGH-VOLTAGESUPPLY 1HVDD=15VHVSS=−15V 0.8 0.6 0.4 0.2 0.2−40−25−10 52035506580Free-AirTemperature(°C) Figure61. 95110125 G006
0 5
7 9 11 13 15 HVDD,PositiveHigh-VoltageSupply(V)G007 Figure62. Copyright©2011,TexasInstrumentsIncorporated 19 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. POSITIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsSAMPLERATE NEGATIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsANALOGSUPPLYVOLTAGE 0.5HVDD=15VHVSS=−15V 0.4 −0.2−0.25 HVSSDynamicCurrent(mA) HVDDDynamicCurrent(mA) −0.30.3 −0.35 0.2−0.4 0.1 −0.45
0 0 0.2 0.4 0.6 0.8
1 fSAMPLE,SampleRate(MSPS) G008 Figure63. −0.5 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G009 Figure64. HVSSDynamicCurrent(mA) NEGATIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsFREE-AIRTEMPERATURE −0.3HVDD=15V −0.35 −0.4 −0.45 −0.5−40−25−10 52035506580Free-AirTemperature(°C) Figure65. 95110125 G010 HVSSDynamicCurrent(mA) NEGATIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsNEGATIVEHIGH-VOLTAGESUPPLY
0 −0.05 −0.1 −0.15 −0.2 −0.25 −0.3 −0.35 −0.4 −0.45 −0.5 −15 −12 −
9 −
6 −
3 0 HVSS,
NegativeHigh-VoltageSupply(V)G011 Figure66. HVSSDynamicCurrent(mA) NEGATIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsSAMPLERATE 0HVDD=15VHVSS=−15V −0.1 −0.2 −0.3 −0.4 −0.5
0 0.2 0.4 0.6 0.8
1 fSAMPLE,SampleRate(MSPS) G012 Figure67. DifferentialNonlinearity(LSB) 1.61.41.2 10.80.60.40.2 0−0.2−0.4−0.6−0.8 −10 DNL 5121024153620482560307235844095ADCOutputCode(LSB)G066 Figure68. 20 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 IntegralNonlinearity(LSB)ADC,OutputCode Amplitude(dB) TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. INL SPECTRALRESPONSE 1.51.20.90.60.3 0−0.3−0.6−0.9−1.2−1.5
0 5121024153620482560307235844095ADCOutputCode(LSB)G067 0−10−20−30−40−50−60−70−80−90−100−110−120−130
0 50100150200250300350400450500 fIN,InputFrequency(kHz) G068 Figure69. Figure70. TEMPERATURESENSOROUTPUTvsFREE-AIRTEMPERATURE 3900 3875 3850 3825 3800 3775 3750 3725 3700−40−25−10 52035506580Free-AirTemperature(°C) Figure71. 95110125 G069 Copyright©2011,TexasInstrumentsIncorporated 21 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 OVERVIEW TheADS8634andADS8638are12-bit,4-and8-channeldevices,respectively.TheADS8634/8featuresoftware-selectablebipolarandunipolarranges,aninternalreferencewithanoptiontouseanexternalreference,andaninternaltemperaturesensor.Independentpower-downcontrolfortheinternalreferenceandtemperaturesensorblocksallowsforoptimalpowerbasedonapplication.Thefollowingsectionsdescribetheindividualblocksandoperation. MULTIPLEXERANDANALOGINPUT TheADS8634/8featuresingleendedinputswithgroundsenseanda4-/8-channel,single-polemultiplexer,respectively.TheADCsamplesthedifferencevoltagebetweenanaloginputpinsAINxandthegroundsensepinAINGND.TheADS8634/8canscantheseanaloginputsineithermanualorauto-scanmode.Inmanualmode,thechannelisselectedforeverysampleviaaregisterwrite;inauto-scanmode,thechannelnumberisincrementedautomaticallyoneveryCSfallingedgeafterthepresentchannelissampled.Itispossibletoselecttheanaloginputsforanautoscanwithregistersettings.Thedevicesautomaticallyscanonlytheselectedanaloginputsinascendingorder. TheADS8634/8offermultiplesoftware-programmableranges±10V,±5V,±2.5V,0Vto5V,and0Vto10Vwitha2.5Vreference.Anyoftheserangescanbeassignedtoanyanaloginput(forinstance,±10VcanbeassignedtoAIN1,±2.5VtoAIN2,0Vto10VcanbeassignedtoAIN3,andsoon).Duringascan(eitherautoormanual),theprogrammedsignalrangeisassignedtotheselectedchannel.Therangeselection,however,canbetemporarilyoverriddenusingtheDINlineforaparticularscan.Thisfeatureisusefulforzoomingintoanarrowrangewhenneeded.RefertoTable11forconfigurationregistersettings. 22 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 Figure72showselectrostaticdischarge(ESD)diodesconnectedtotheHVDDandHVSSsupplies.Makesurethesediodesdonotturnonbykeepingtheanaloginputswithinthespecifiedrange. HVDD AIN0 HVSSHVDD TemperatureSensor AIN1 HVSS SARADC AIN3/7AINGND HVDD HVSSHVDD HVSS Figure72.AnalogInputs Copyright©2011,TexasInstrumentsIncorporated 23 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TheADS8634/8samplethevoltagedifference(VAINx–VAINGND)betweentheselectedanaloginputchannelandtheAINGNDpin.TheADS8634/8allowa±0.2VrangeonAINGND.Thisfeatureisusefulinmodularsystemswherethesensor/signalconditioningblockisremovedfromtheADCandwhentherecouldbeadifferenceinthe groundpotentialofthesensor/signalcondionerfromtheADCground.Insuchcases,itismendedtorun separatewiresfromtheAINGNDterminalofthedevicetothesensor/signalconditionerground. REFERENCE TheADS8634/8measuretheanaloginputsignalsrelativetothevoltagereferenceusingeitheraninternalprecision2.5Vvoltagereference(Figure73)oranexternalvoltagereference(Figure74).Binary-weightedcapacitorsareswitchedontothereferenceterminalduringconversion.TheswitchingfrequencyisthesameastheSCLKfrequency.Whetheritisaninternalorexternalreference,besuretodecoupletheREFterminaltoREFGNDwitha10µFcapacitor.PlacethecapacitorclosetotheREFPandREFGNDpins. AVDDAGND InternalReference 10F REFREFGND ADC ConfigurationRegister Figure73.OperationUsingTheInternalReference(RefertoTable11formoredetailsontheconfigurationregistersettings) AVDDAGND AVDDPlane InternalReference REF30/50xx AGNDPlane REF1FREFGND ADC ConfigigurationRegister Figure74.OperationUsinganExternalReference(RefertoTable11formoredetailsontheconfigigurationregistersettings) 24 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 Thesedevicesallowtheuseofanexternalreferenceintherangeof2.0Vto3.0V.Thenominalinputranges±10V,±5V,±2.5V,0Vto5V,and0Vto10Vassumea2.5Vreference;adifferentreferencevoltagescalesthefull-scalerangesproportionately.Forexample,ifa3.0Vreferenceisusedandthe±10Vrangeisselected,theactualinputrangeisscaledby(3.0/2.5)forafull-scalerangeof±12V. Theinternalreferencecanbeenabled/disabledthroughtheconfigurationregister.Thereferenceblockispowereddownwhentheinternalreferenceisdisabled.Ensurethattheinternalreferenceisdisabledwhentheexternalreferenceisconnected.Theexternalreferenceisthedefaultselectionafterpower-onorreset. TEMPERATURESENSOR TheADS8634/8featureanon-chiptemperaturesensorasshowninFigure75.Thedevicetemperaturecanbereadatanytimeduringascan,eitherinautoormanualmode.Therearethreeregistersassociatedwiththetemperaturesensoroperation.Thetemperaturesensorcanbeenabled/disabledthroughtheAux-Configconfigurationregister.Disablingthetemperaturesensorpowersdownthetemperatureblock.Itisnecessarytoenable(powerup)thetemperaturesensoratleastonecyclebeforethedevicetemperaturesensorisselectedwiththechannelsequencingcontrolregisters(manual/auto).ThisselectionoverridestheinputchannelscansequenceandrangeselectionandconnectstheADCinputtoaninternaltemperaturesensor.Thetemperaturesensormustbedeselectedwithchannelsequencingcontrolregisters(manual/auto)toresumenormalscanning.Incaseofauto-sequencing,thedevicestartsscanningfromwhereitleftoffbeforethetemperaturemeasurement.Thetemperaturesensorisdisabledbydefaultafterpower-onorreset. AVDDAGND ChSeqControlReg ConfigReg AIN0AIN1AIN2 TempSensor ADC AIN3/7AINGND Figure75.ReadingtheADS8634/8Temperature(RefertoTable11formoredetailsonconfigurationregistersettings) Thetemperaturesensortransferfunctionfollowsastraightline,asshowninEquation1: OutputCode=mREF×DeviceTemperaturein°C+CREF
(1) Equation1canbere-writtenasEquation2:DeviceTemperaturein°C=(OutputCode–CREF)/mREF where: mREF=theslope, andCREF=theoffset(inADCoutputcode)ofthetemperaturesensortransferfunction
(2) BothmREFandCREFchangewiththereferencevoltage.TheinitialvaluesofmREFandCREFata2.5Vreferenceare:mREF_2.5=0.47andCREF_2.5=3777.2 Copyright©2011,TexasInstrumentsIncorporated 25 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ValuesofmREFandCREFforanyreferencevoltageotherthan2.5VcanbecalculatedusingEquation3andEquation4: mREF=mREF_2.5×2.5/VREF
(3) CREF=(CREF_2.5–3584)×2.5/VREF+3584
(4) Forexample,ata2Vreference:mREF_2=0.47×2.5/2=0.59andCREF_2=(3777.2–3584)×2.5/2+3584=3825.5 Forthereferencevoltageused,Equation2canberewrittedusingmREFandCREFascalculatedinEquation3andEquation4. Table3canbeusedasquickreferencefortemperaturesensortransferfunctionattypicalreferencevalues. Table3.TemperatureSensorTransferFunctionatTypicalReferenceValues REFERENCEVOLTAGE(V)22.53 TRANSFERFUNCTIONDevicetemperaturein°C=(outputcode–3825.5)/0.59Devicetemperaturein°C=(outputcode–3777.2)/0.47Devicetemperaturein°C=(outputcode–3745.0)/0.39 DATAFORMAT TheADS8634/8output12-bitsofADCconversionresultsinbinaryformat(MSBfirst)forallranges,asshowninTable4.Figure76showstheADCtransferfunctionforbipolarsignalranges.TheunipolarrangeoutputisshowninTable5andFigure77showsthetransferfunction. Table4.BipolarRangeIdealOutputCodes
(1) ±10VRANGE(V)≥10×(211–1)/211
(2) 10/211 0–10/211≤–10×(211–1)/211 INPUTSIGNAL(AINx–AINGND) ±5VRANGE(V)≥5×(211–1)/211 5/211 0–5/211≤–5×(211–1)/211 ±2.5VRANGE(V)≥2.5×(211–1)/211 2.5/211 0–2.5/211≤–2.5×(211–1)/211 IDEALOUTPUTCODE FFFh801h800h7FFh000h
(1)Excludesnoise,offsetandgainerrors.
(2)LSBsizeforthebipolarranges=positive(ornegative)full-scale/211.TheADS8634/8offer12-bitresolutionacrosstheentirerangefrom positivefull-scaletonegativefull-scale;inotherwords,theresolutionforhalfrangefrom'0'topositive(ornegative)full-scaleis11bits.Forexample,a1LSBfora±10Vrangeis10/211. Table5.UnipolarRangeIdealOutputCodes
(1) INPUTSIGNAL(AINx–AINGND) 0VTO10VRANGE(V)≥10×(212–1)/21210/212<10/212 0VTO5VRANGE(V)≥5×(212–1)/2125/212<5/212 IDEALOUTPUTCODEFFFh001h000h
(1)Excludesnoise,offsetandgainerrors. 26 Copyright©2011,TexasInstrumentsIncorporated FFFh ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ADCCode 800h 001h NegativeFSR+1LSB 0AnalogInput(AINx PositiveFSR1LSB AINGND) Figure76.TransferFunctionforBipolarSignalRanges FFFh ADCCode 800h 001h 1LSB FSR/2AnalogInput(AINx FSR–1LSBAINGND) Figure77.TransferFunctionforUnipolarSignalRanges Copyright©2011,TexasInstrumentsIncorporated 27 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 AL_PD:USER-CONFIGURABLEPIN TheADS8634/8featureauser-configurableAL_PDpin.Thispincaneitherbeconfiguredasanalarmoutput(AL)orasapower-downcontrolpin(PD).RefertothePage0,RegisterDescriptionsfortheADS8638andPage0,RegisterDescriptionsfortheADS8634sectionsfordetails. Whenprogrammedasanalarmoutput,anactive-highalarmisflaggedonthispinifthereisahighorlowalarmonanychannel.TheAlarmFunctionalitysectiondescribesthepindetails. WhenprogrammedasPD,theAL_PDpinfunctionsasanactive-lowpower-downinputpin.Poweringdownthroughthispinisasynchronous.Thedevicespowerdownimmediatelyafterthepingoeslow.ThePower-DownFunctionalitysectiondescribesthepindetails. ThispinisconfiguredasaPDinputbydefaultafterpower-onorreset. AlarmFunctionality TheADS8634/8outputanactive-highalarmontheAL_PDpinwhenitisprogrammedasanAL.ALissynchronousandchangesitsstateonthe16thSCLKrisingedge.AhighlevelonALindicatesthereisanactivealarmononeormorechannels.Thispincanbewiredtointerruptthehostinput.Whenanalarminterruptisreceived,thealarmflagregistersarereadtodeterminewhichchannelshaveanalarm. TheADS8634/8featureindependently-programmablealarmsforeachchannel.Therearetwoalarmsperchannel(lowandhighalarm)andeachalarmthresholdhasaseparatehysteresissetting. TheADS8634/8setahighalarmwhenthedigitaloutputforaparticularchannelexceedsthehighalarmupperlimit(highalarmthresholdT+hysteresisH).Thealarmresetswhenthedigitaloutputforthechannelislessthanorequaltothehighalarmlowerlimit(highalarmT–H).ThisfunctionisshowninFigure78. H_ALARMOn Alarm H_ALARMOff (T–H)(T+H+1)ADCOutputNOTE:T=alarmthresholdandH=hysteresis. Figure78.High-AlarmHysteresis Similarly,theloweralarmistriggeredwhenthedigitaloutputforaparticularchannelfallsbelowthelowalarmlowerlimit(lowalarmthresholdT–H).Thealarmresetswhenthedigitaloutputforthechannelisgreaterthanorequaltothelowalarmhigherlimit(lowalarmT+H).ThisfunctionisshowninFigure79. L_ALARMOn L_ALARMOff Alarm (T–H–1)(T+H) ADCOutput NOTE:T=alarmthresholdandH=hysteresis. Figure79.Low-AlarmHysteresis 28 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 Figure80showsafunctionalblockdiagramforasingle-channelalarm.Foreachhighandlowalarmtherearetwoflags:ActiveAlarmFlagandTrippedAlarmFlag;refertotheAlarmFlagsfortheADS8638(Read-Only)andAlarmFlagsfortheADS8634(Read-Only)sectionsformoredetails.Theactivealarmflagistriggeredwhenanalarmconditionisencounteredforaparticularchannel;theactivealarmflagresetswhenthealarmshutsoff.Atrippedalarmflagsetsanalarmconditioninthesamemannerasitdoesforanactivealarmflag;however,itremainslatchedandresetsonlywhentheappropriatealarmflagregisterisread. AllChannelH/LAlarms AlarmThresholdChanneln+/- HysteresisChanneln ADCOutputChanneln ADC + 16thSCLK SQRQ AL_PD ProgrammedasAlarmOutput ActiveAlarmFlagChanneln TrippedAlarmFlagChanneln AlarmFlagRead SDO Figure80.AlarmFunctionality Power-DownFunctionality TheADS8634/8featureapower-down/upcontrolthroughtheprogrammableAL_PDpinorthechannelsequencingcontrolregisters;seetheChannelSequencingControlRegistersfortheADS8638andChannelSequencingControlRegistersfortheADS8634sectionsformoredetails.ThisfeatureisextremelyusefulforsavingpowerwhilerunningtheADS8634/8ataslowerspeed,orforacquiringdataatfull-speedinburstsandthenwaitinginapower-downstateforthenextacquisitionstartevent.Figure81throughFigure84describeentrytoandexitfromthepower-downstate. TheAL_PDpincanbeprogrammedasapower-downcontrolpin.TheAL_PDpin,whenprogrammedasPD,isshowninFigure81.AlowonAL_PDpowersdownthedeviceimmediately;thisactionisasynchronousoperation.DataonDOUTarenotvalidwhenthedeviceisinapower-downstate. AL_PD ProgrammedasPD Power-DownStateActive(Internal) Power-Down DOUT Validdataterminatesonpowerdown. Figure81.Power-DownUsingtheAL_PDPin Copyright©2011,TexasInstrumentsIncorporated 29 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 AhighlevelonAL_PDactsasapower-uprequestandthepower-upsequencebeginsonthenextCSfalling edge.Thedeviceisactiveaftertd(PWRUP).Thefirstvalidacquisitioninitiatesinthefirstdataframe(withaCSfallingedge)afterapower-updelay.Thefirstvaliddataarepresentedintheseconddataframeafterthedevice attainsanactivestate,asshowninFigure82. CSSCLK 1216 1216 1216 1216 AL_PDProgrammedasPD Power-DownState(Internal) Power-Down Td(PWRUP)Power-UpDelay Active DOUT InvalidData InvalidData InvalidData ValidData Figure82.Power-UpViatheAL_PDPin ValidData Thepower-down/upoperationcanalsobecontrolledwithregistersettings.SeetheChannelSequencingControlRegistersfortheADS8638andChannelSequencingControlRegistersfortheADS8634sectionsfordetails.Figure83
C •小占位面积：4mm×4mmQFN封装 说明 ADS8634andADS8638(ADS8634/8)是12位的模数转换器（ADCs）,他们能够在1MSPS下测量达到±10V的输入电压。
使用逐次求近寄存器(SAR)核心，这些模数转换器可以提供一个采样保持前端的无延迟转换。
ADS8634包括一个输入复用器(mux)来测量最多四位的输入。
ADS8638可以测量最多八位的输入。
除了输入复用器，ADS8634/8特别装有内部温度传感器、电压基准和一个数字比较器以为每个输入设定报警阀值；因此，最少数量的外部部件是必需的。
一个简单的SPI兼容接口提供了通信和控制。
数字电源可一直工作在5伏电压或下至1.8伏电压以便与多种多样的处理器和控制器进行直接连接。
对于那些要求严格的测量仪器，ADS8634/8可以在工业温度–40°C到+125°C下工作并有小规格的QFN-24封装。
应用 •可编程逻辑控制器•数据采集系统•高速、闭合回路系统•数字电源 AIN0AIN1AIN2AIN3 HVDDMUX AVDDREF REF DVDD AlarmThreshold Comparator ADCSPI AINGND TempSensor HVSS ADS8634 AGND REFGND DGND HVDD AL_PD CS,SCLK,DIN,DOUT AIN0AIN1AIN2AIN3AIN4AIN5AIN6AIN7 AINGND TempSensor MUXHVSS AVDDREF REF DVDD AlarmThreshold Comparator ADCSPI ADS8638 AGND REFGND DGND AL_PD CS,SCLK,DIN,DOUT
1 Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.2SPIisatrademarkofMotorola.3Allothertrademarksarethepropertyoftheirrespectiveowners. PRODUCTIONDATAinformationiscurrentasofpublicationdate.ProductsconformtospecificationsperthetermsoftheTexasInstrumentsstandardwarranty.Productionprocessingdoesnotnecessarilyincludetestingofallparameters. Copyright©2011,TexasInstrumentsIncorporatedEnglishDataSheet:SBAS541A ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ThisintegratedcircuitcanbedamagedbyESD.TexasInstrumentsmendsthatallintegratedcircuitsbehandledwithappropriateprecautions.Failuretoobserveproperhandlingandinstallationprocedurescancausedamage. ESDdamagecanrangefromsubtleperformancedegradationpletedevicefailure.Precisionintegratedcircuitsmaybemoresusceptibletodamagebecauseverysmallparametricchangescouldcausethedevicenottomeetitspublishedspecifications. PRODUCTADS8634ADS8638 DEVICECOMPARISON
(1) RESOLUTION CHANNELS 412-Bit
8 SAMPLERATE1MSPS
(1)Forthemostcurrentpackageandorderinginformation,seethePackageOptionAddendumattheendofthisdocument,orvisitthedeviceproductfolderat. ABSOLUTEMAXIMUMRATINGS Overoperatingfree-airtemperaturerange,unlessotherwisenoted.
(1) AINntoAGNDorAINGNDtoAGND AVDDtoAGNDorDVDDtoDGND HVDDtoAGND HVSStoAGND HVDDtoHVSS DigitalinputvoltagetoDGND DigitaloutputtoDGND Operatingtemperaturerange Storagetemperaturerange ESDratings,allpins Humanbodymodel(HBM)Chargeddevicemodel(CDM) VALUEHVSS–0.3toHVDD+0.3 –0.3to7–0.3to18–18to0.3–0.3to33–0.3toDVDD+0.3–0.3toDVDD+0.3–40to+125–65to+150 ±2000±500 UNITVVVVVVV°C°CVV
(1)Stressesbeyondthoselistedunderabsolutemaximumratingsmaycausepermanentdamagetothedevice.Thesearestressratingsonly,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedundermendedoperatingconditionsisnotimplied.Exposuretoabsolute–maximum–ratedconditionsforextendedperiodsmayaffectdevicereliability.ThesearestressratingsonlyandfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthosespecifiedintheElectricalCharacteristicstableisnotimplied.
2 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ELECTRICALCHARACTERISTICS:ADS8634,ADS8638 Minimum/maximumspecificationsatTA=–40°Cto+125°C,fSAMPLE=1MSPS,HVDD=10Vto15V,HVSS=–10Vto–15V,AVDD=4.75Vto5.25V,DVDD=2.7Vto3.6V,andVREF=2.5V,unlessotherwisenoted.Typicalspecificationsat+25°C,fSAMPLE=1MHz,HVDD=10V,HVSS=–10V,AVDD=3.3V,DVDD=3.3V,andVREF=2.5V,unlessotherwisenoted. ADS8634,ADS8638 PARAMETER TESTCONDITIONS MIN TYP MAXUNIT ANALOGINPUT ±2.5
V Full-scaleinputspan
(1) Bipolarranges,VREF=2.5V ±
5 V ±10
V Unipolarranges,VREF=2.5V 0to5
V 0to10
V AINxabsoluteinputrange HVSS HVDD
V AINGNDabsoluteinputrange –0.2 0.2
V Inputcapacitance
8 pF Inputleakagecurrent At+125°
C 200 nA SYSTEMPERFORMANCE Resolution 12 Bits Nomissingcodes 12 Bits Integrallinearity –1.5+0.9/–0.9 1.5LSB
(2) Differentiallinearity –1.0+0.9/–0.5 1.6LSB Offseterror
(3) –
3 ±0.8 3LSB Offseterrordrift 0.75 ppmFS/°C( 4) Gainerror
(5)GainerrordriftNoise Power-supplyrejection Crosstalk Isolationcrosstalk Memorycrosstalk SAMPLINGDYNAMICSConversiontimeAcquisitiontimeMaximumthroughputrateAperturedelayStepresponse AtFFChoutputcodewith250mVPPand480HzrippleonAVDDCrosstalkonchannel0withchannel0permanentlyselected,2kHzfull-scalesinewaveonchannel1,allotherchannelsgroundedCrosstalkonchannel0,2kHzfull-scalesinewaveonchannel1,allotherchannelsgrounded,devicescanschannel0andchannel1alternately At20MHzSCLK,DVDD=2.7Vto5.25VAVDD=2.7Vto5.25VAt20MHzSCLK,DVDD=2.7Vto5.25V –
8 ±
2 1.2 0.33 –87 –110 –81 2501 13250 8LSBppm/°CLSBdB dB dB 750 ns ns 1MSPS ns ns
(1)Idealinputspan;doesnotincludegainoroffseterror.
(2)LSBmeansleastsignificantbit.
(3)Measuredrelativetoanidealfull-scaleinput.(4)ppmFS/°Cisdriftmeasuredinpartspermillionoffull-scalerangeperdegreecentigrade.
(5)Doesnotincludereferencedrift. Copyright©2011,TexasInstrumentsIncorporated
3 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ELECTRICALCHARACTERISTICS:ADS8634,ADS8638(continued) Minimum/maximumspecificationsatTA=–40°Cto+125°C,fSAMPLE=1MSPS,HVDD=10Vto15V,HVSS=–10Vto–15V,AVDD=4.75Vto5.25V,DVDD=2.7Vto3.6V,andVREF=2.5V,unlessotherwisenoted.Typicalspecificationsat+25°C,fSAMPLE=1MHz,HVDD=10V,HVSS=–10V,AVDD=3.3V,DVDD=3.3V,andVREF=2.5V,unlessotherwisenoted. ADS8634,ADS8638 PARAMETER TESTCONDITIONS MIN TYP MAXUNIT DYNAMICCHARACTERISTICS Totalharmonicdistortion
(6)(THD) At1kHzAt100kHz –81 dB –80 dB Signal-to-noiseratio(SNR) At1kHzAt100kHz 71 71.8 dB 71.1 dB Signal-to-noiseanddistortionratio(SINAD) At1kHzAt100kHz 70.1 71.3 dB 70.5 dB Spurious-freedynamicrange(SFDR) At1kHzAt100kHz –83 dB –80 dB Full-powerbandwidth At–3dB
1 MHz DIGITALINPUT/OUTPUT Logicfamily CMOS
V VIH 0.7DVDD
V VILLogiclevel VOH With20pFloadonSDO 0.8DVDD 0.3DVDD
V V VOL With20pFloadonSDO 0.2DVDD
V EXTERNALVOLTAGEREFERENCE Referenceinputvoltagerange VREF 3.0or 2.0 AVDD,
V whichever isless INTERNALVOLTAGEREFERENCE Referenceoutputvoltage 2.5
V Initialuracy –1.2 1.2 % TemperaturedriftDrivecurrent,source
(7) 20 ppm/°
C 750 µ
A Drivecurrent,sink 20 µ
A Driveroutputimpedance
1 Ω Turn-onsettlingtime With10µFdecouplingcapacitorfromREFtoREFGND
9 ms INTERNALTEMPERATURESENSOR Absoluteuracy
5 %ofFSR
(6)Calculatedonthefirstnineharmonicsoftheinputfrequency.
(7)Internalreferenceoutputisshort-circuitprotected.Incaseofshort-circuittoground,thedrivecurrentislimitedtothisvalue.
4 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ELECTRICALCHARACTERISTICS:ADS8634,ADS8638(continued) Minimum/maximumspecificationsatTA=–40°Cto+125°C,fSAMPLE=1MSPS,HVDD=10Vto15V,HVSS=–10Vto–15V,AVDD=4.75Vto5.25V,DVDD=2.7Vto3.6V,andVREF=2.5V,unlessotherwisenoted.Typicalspecificationsat+25°C,fSAMPLE=1MHz,HVDD=10V,HVSS=–10V,AVDD=3.3V,DVDD=3.3V,andVREF=2.5V,unlessotherwisenoted. ADS8634,ADS8638 PARAMETER TESTCONDITIONS MIN TYP MAXUNIT POWER-SUPPLYREQUIREMENTS VAVDD 2.7 3.3 5.25
V Supplyvoltage VDVDDVHVDD 10V
V VHVSS 10V
(8) AtVAVDD=2.7Vto5.25V,additionalAVDDcurrentwithinternalreferenceonandtemperaturesensoroff 180 µ
A IAVDD(temp)
(9) AtVAVDD=2.7Vto5.25V,additionalAVDDcurrentwithinternaltemperaturesensoronandinternalreferenceoff 400 µ
A HVDDsupplycurrent IHVDD(dynamic)IHVDD(static) HVDD=15Vand1MSPSthroughputHVDD=15VanddevicestaticwithSCLKoff 270 350 µ
A 5 µ
A HVSSsupplycurrent IHVSS(dynamic)IHVSS(static) HVSS=–15Vand1MSPSthroughputHVSS=–15VanddevicestaticwithSCLKoff 520 µ
A 5 µ
A DVDDsupplycurrent(10) IDVDD DVDD=3.3V,fSAMPLE=1MSPS,DOUTload=20pF 2.5 mA Power-downstate AVDDcurrentHVDDcurrent SCLKoff,internalreferenceandtemperaturesensoroffSCLKon,internalreferenceandtemperaturesensoroff 10 µ
A 160 µ
A 5 µ
A HVSScurrent
5 µ
A TEMPERATURERANGE Specifiedperformance –40 +125 °
C
(8)AddIAVDD(ref)toIAVDD(dynamic)orIAVDD(static)(asapplicable),ifinternalreferenceisselected.
(9)AddIAVDD(temp)toIAVDD(dynamic)orIAVDD(static)(asapplicable),ifinternaltemperaturesensorisenabled.(10)IDVDDconsumesonlydynamiccurrent.IDVDD=CLOAD×VDVDD×numberof0→1transitionsinDOUT×fSAMPLE.IDVDDisa load-dependentcurrent;thereisnocurrentwhentheoutputisnottoggling. THERMALINFORMATION THERMALMETRIC
(1) θJAθθJBψJTψJBθJCbot Junction-to-ambientthermalresistanceJunction-to-case)thermalresistanceJunction-to-boardthermalresistancecharacterizationparameterJunction-to-boardcharacterizationparameterJunction-to-case(bottom)thermalresistance
(1)有关传统和新的热度量的更多信息，请参阅IC封装热度量应用报告SPRA953。
ADS8634/8RGERGE 24PINS32.630.53.30.49.32.6 UNITS°C/W Copyright©2011,TexasInstrumentsIncorporated
5 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 PARAMETERMEASUREMENTINFORMATION TIMINGDIAGRAM tsu(CS-SCLK)CS 1/fSAMPLE SCLK DOUT td(CS-DO) DIN 1R1F2
3 th(SCLK-DOUT)
4 5 td(SCLK-DOUT) tsu(DIN-SCLK) 12th(SCLK-DIN) 13 14 tw(SCLK_H) 15 16R16F tw(SCLK_L) td(CS-DOHZ) Acquisition(Internal) tc Table1.TimingRequirements
(1)(2)
(3) PARAMETER tc Conversiontime t(ACQ) Acquisitiontime td(CS-DO) Delaytime,CSlowtofirstdata(D0toD15)out tsu(CS-SCLK)Setuptime,CSlowtofirstSCLKrisingedge td(SCLK-DOUT)Delaytime,SCLKfallingtoDOUT th(SCLK-DOUT)Holdtime,SCLKfallingtoDOUTvalid td(CS-DOHZ)DelaytimeCShightoDOUThigh-z TESTCONDITIONSDVDD=1.8V DVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5V ADS8634,ADS8638 MIN TYP 250250250 26.018.515.5 5.55.04.77.36.45.9 t(ACQ) MAX151515 52.540.030.5 51.533.025.3 31.022.016.4 UNITSCLKSCLKSCLK nsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsns
(1)Allspecificationsat–40°Cto+125°C,unlessotherwisenoted.(2)1.8Vspecificationsapplyfrom1.65Vto1.95V;3Vspecificationsapplyfrom2.7Vto3.6V;and5Vspecificationsapplyfrom4.75Vto 5.25V.
(3)With20pFloadonDOUT.
6 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 tsu(DIN-SCLK)th(SCLK-DIN)tW(SCLK_H)tW(SCLK_L)fSCLKfSAMPLE PARAMETERMEASUREMENTINFORMATION(continued)Table1.TimingRequirements
(1)(2)
(3)(continued) PARAMETERSetuptime,DINvalidtoSCLKrisingedgeHoldtime,SCLKrisingtoDINvalidPulseduration,SCLKhighPulseduration,SCLKlowSCLKfrequencySamplingfrequency TESTCONDITIONSDVDD=1.8V DVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5VDVDD=1.8VDVDD=3VDVDD=5V ADS8634,ADS8638 MIN TYP 7.0 6.0 5.0 9.0 8.0 7.0 25 20 20 25 20 20 MAX 1620200.84 11 UNITnsnsnsnsnsnsnsnsnsnsnsnsMHzMHzMHz MSPSMSPSMSPS POWER-UPTIMINGREQUIREMENTS CSSCLK 1216 1216 1216 1216 AL_PDProgrammedasPD Power-DownState(Internal) Power-Down Td(PWRUP)Power-UpDelay Active DOUT InvalidData InvalidData InvalidData ValidData ValidData Table2.TIMINGREQUIREMENTS
(1) td(PWRUP)
(2) PARAMETERPower-updelayfromfirstCSaftermandInvalidconversionsafterdeviceisactive(poweredup) ADS8634,ADS8638 MIN TYP
(1)Allspecificationsat–40°Cto+125°C,unlessotherwisenoted.
(2)Power-uptimeexcludesinternalreferenceandtemperaturesensor. MAX11 UNITµs Conversion Copyright©2011,TexasInstrumentsIncorporated
7 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 PINCONFIGURATIONS RGEPACKAGE4mm×4mmQFN-24 (TOPVIEW) 24REF23REFGND22AL_PD21DVDD20DGND19DOUT AVDD1AGND2AGND3 NC4AINGND5 NC6 ThermalPad(BottomSide) 18DIN17SCLK16CS15HVSS14HVDD13NC NC7AIN38AIN29AIN110AIN011 NC12 PINNUMBER1 2,34,6,7,12,13 58910111415161718192021 22 23 24 Figure1.ADS8634PinConfiguration NAMEAVDDAGND NCAINGND AIN3AIN2AIN1AIN0HVDDHVSSCSSCLKDINDOUTDGNDDVDD AL_PD REFGND REF ADS8634PINASSIGNMENTS FUNCTION DESCRIPTION AnalogpowersupplyAnalogpowersupply AnalogpowersupplyAnalogground — Thesepinsarenotinternallyconnected;donotfloatthesepins. ItismendedtoconnectthesepinstoAGND. Input Commonforallanaloginputchannels;actsasgroundsenseterminal Analoginput Analoginputchannel3 Analoginput Analoginputchannel2 Analoginput Analoginputchannel1 Analoginput Analoginputchannel0 High-voltagepowersupplyHigh-voltagepositivesupplyformultiplexerchannels High-voltagepowersupplyHigh-voltagenegativesupplyformultiplexerchannels Digitalinput Chipselectinput Digitalinput Serialclockinput Digitalinput Serialdatainput Digitaloutput Serialdataoutput DigitalpowersupplyDigitalground DigitalpowersupplyDigitalI/Osupply Digitaloutput Activehigh,outputindicatesalarm(programmedasanoutputpin) Digitalinput Activelow,asynchronouspower-down.Thedevicefeaturesaninternal,weakpull-upresistorfromtheAL_PDpintoDVDD.TheAL_PDpincanalsobefloatedwhenprogrammedasapower-downinput.(Thedefaultconditionforthispinisprogrammedasapower-downinputpin.) Analoginput Referencegroundinputtodevicewhenanexternalreferenceisselected.Thispinactsasareferencedecouplinggroundterminalwhenaninternalreferenceisselected. Analoginput Referenceinputtodevicewhenanexternalreferenceisselected.Thispinactsasareferencedecouplingterminalwhenaninternalreferenceisselected.
8 Copyright©2011,TexasInstrumentsIncorporated RGEPACKAGE4mm×4mmQFN-24 (TOPVIEW) ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 24REF23REFGND22AL_PD21DVDD20DGND19DOUT AVDD1AGND2AGND3 NC4AINGND5 AIN76 ThermalPad(BottomSide) 18DIN17SCLK16CS15HVSS14HVDD13AIN0 AIN67AIN58AIN49AIN310AIN211AIN112 Figure2.ADS8638PinConfiguration PINNUMBER1 2,3456789101112131415161718192021 22 23 24 NAMEAVDDAGND NCAINGND AIN7AIN6AIN5AIN4AIN3AIN2AIN1AIN0HVDDHVSSCSSCLKDINDOUTDGNDDVDD AL_PD REFGND REF ADS8638PINASSIGNMENTS FUNCTION DESCRIPTION AnalogpowersupplyAnalogpowersupply AnalogpowersupplyAnalogground — Thispinisnotinternallyconnected;donotfloatthispin. ItismendedtoconnectthispintoAGND. Input Commonforallanaloginputchannels;actsasgroundsenseterminal Analoginput Analoginputchannel7 Analoginput Analoginputchannel6 Analoginput Analoginputchannel5 Analoginput Analoginputchannel4 Analoginput Analoginputchannel3 Analoginput Analoginputchannel2 Analoginput Analoginputchannel1 Analoginput Analoginputchannel0 High-voltagepowersupplyHigh-voltagepositivesupplyformultiplexerchannels High-voltagepowersupplyHigh-voltagenegativesupplyformultiplexerchannels Digitalinput Chipselectinput Digitalinput Serialclockinput Digitalinput Serialdatainput Digitaloutput Serialdataoutput DigitalpowersupplyDigitalground DigitalpowersupplyDigitalI/Osupply Digitaloutput Activehigh,outputindicatingalarm(programmedasanoutputpin) Digitalinput Activelow,asynchronouspower-down(programmedasaninputpin,defaultcondition) Analoginput Referencegroundinputtodevicewhenanexternalreferenceisselected.Thispinactsasreferencedecouplinggroundterminalwhenaninternalreferenceisselected. Analoginput Referenceinputtodevicewhenanexternalreferenceisselected.Thispinactsasreferencedecouplingterminalwhenaninternalreferenceisselected. Copyright©2011,TexasInstrumentsIncorporated
9 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. DifferentialNonlinearity(LSB) DNLvsANALOGSUPPLYVOLTAGE 1.6 1.4 1.2 MaximumDNL
1 0.8 0.6 0.4 0.2
0 −0.2 MinimumDNL −0.4 −0.6 −0.8 −
1 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G013 Figure3. DifferentialNonlinearity(LSB) 1.61.41.2 10.80.60.40.2 0−0.2−0.4−0.6−0.8 −1±2.5V DNLvsSIGNALRANGE MaximumDNL MinimumDNL ±5V ±10V 0−5V SignalRange Figure4. 0−10V G014 DifferentialNonlinearity(LSB) 1.61.41.2 10.80.60.40.2 0−0.2−0.4−0.6−0.8 −12 DNLvsREFERENCEVOLTAGE MaximumDNL MinimumDNL 2.2 2.4 2.6 2.8
3 ReferenceVoltage(V)G015 Figure5. DifferentialNonlinearity(LSB) DNLvsCHANNELNUMBER 1.6 1.4 1.2 MaximumDNL
1 0.8 0.6 0.4 0.2
0 −0.2 MinimumDNL −0.4 −0.6 −0.8 −
1 0
1 2
3 4
5 6
7 ChannelNumberG016 Figure6. DifferentialNonlinearity(LSB) 1.61.41.2 10.80.60.40.2 0−0.2−0.4−0.6−0.8 −1−40 DNLvsFREE-AIRTEMPERATURE MaximumDNL MinimumDNL−25−105203550658095 Free-AirTemperature(°C) Figure7. 110125 G017 DifferentialNonlinearity(LSB) DNLvsPOSITIVEHIGH-VOLTAGESUPPLY 1.6 1.4 MaximumDNL 1.2
1 0.8 0.6 0.4 0.2
0 −0.2 MinimumDNL −0.4 −0.6 −0.8 −
1 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G018 Figure8. 10 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. INLvsANALOGSUPPLYVOLTAGE INLvsSIGNALRANGE 1.5 1.5 1.2 MaximumINL 0.9 1.2 MaximumINL 0.9 IntegralNonlinearity(LSB) IntegralNonlinearity(LSB) 0.6 0.6 0.3 0.3 0MinimumINL −0.3 0−0.3MinimumINL −0.6 −0.6 −0.9 −0.9 −1.2 −1.2 −1.5 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G019 −1.5±2.5V ±5V ±10V 0−5V SignalRange 0−10V G020 Figure9. Figure10. IntegralNonlinearity(LSB) 1.51.20.90.60.3 0−0.3−0.6−0.9−1.2−1.5
2 INLvsREFERENCEVOLTAGE MaximumINL MinimumINL 2.2 2.4 2.6 2.8
3 ReferenceVoltage(V)G021 Figure11. IntegralNonlinearity(LSB) INLvsCHANNELNUMBER 1.5 1.2 MaximumINL 0.9 0.6 0.3
0 −0.3 MinimumINL −0.6 −0.9 −1.2 −1.5
0 1
2 3
4 5
6 7 ChannelNumberG022 Figure12. IntegralNonlinearity(LSB) INLvsFREE-AIRTEMPERATURE 1.5 1.2 MaximumINL 0.9 0.6 0.3 0−0.3MinimumINL −0.6 −0.9 −1.2 −1.5−40−25−105203550658095Free-AirTemperature(°C) Figure13. 110125 G023 IntegralNonlinearity(LSB) INLvsPOSITIVEHIGH-VOLTAGESUPPLY 1.5 1.2 MaximumINL 0.9 0.6 0.3
0 −0.3 MinimumINL −0.6 −0.9 −1.2 −1.5 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G024 Figure14. Copyright©2011,TexasInstrumentsIncorporated 11 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. OFFSETERRORvsANALOGSUPPLYVOLTAGE OFFSETERRORvsSIGNALRANGE 2.5 2.5
2 2 1.5 1.5 OffsetError(LSB) OffsetError(LSB)
1 1 0.5 0.5
0 0 −0.5 −0.5 −
1 −
1 −1.5 −1.5 −
2 −
2 −2.5 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD
(V)G025 −2.5±2.5V ±5V ±10V 0−5V SignalRange 0−10V G026 Figure15. Figure16. OffsetError(LSB) OFFSETERRORvsREFERENCEVOLTAGE 2.5
2 1.5
1 0.5
0 −0.5 −
1 −1.5 −
2 −2.5
2 2.2 2.4 2.6 2.8
3 Reference
Voltage(V)G027 Figure17. OffsetError(LSB) OFFSETERRORvsCHANNELNUMBER 2.5
2 1.5
1 0.5
0 −0.5 −
1 −1.5 −
2 −2.5
0 1
2 3
4 5
6 7 ChannelNumberG028 Figure18. OffsetError(LSB) OFFSETERRORvsFREE-AIRTEMPERATURE 2.5
2 1.5
1 0.5
0 −0.5 −
1 −1.5 −
2 −2.5−40−25−10 52035506580Free-AirTemperature(°C) 95110125 G029 Figure19. OffsetError(LSB) OFFSETERRORvsPOSITIVEHIGH-VOLTAGESUPPLY 2.5
2 1.5
1 0.5
0 −0.5 −
1 −1.5 −
2 −2.5 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G030 Figure20. 12 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. GAINERRORvsANALOGSUPPLYVOLTAGE GAINERRORvsSIGNALRANGE
8 8
6 6
4 4 GainError(LSB) GainError(LSB)
2 2
0 0 −
2 −
2 −
4 −
4 −
6 −
6 −
8 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G031 Figure21. −8±2.5V ±5V ±10V SignalRange Figure22. 0−5V 0−10V G032 GainError(LSB) GAINERRORvsREFERENCEVOLTAGE
8 6
4 2
0 −
2 −
4 −
6 −
8 2 2.2 2.4 2.6 2.8
3 ReferenceVoltage(V)G033 Figure23. GainError(LSB) GAINERRORvsCHANNELNUMBER
8 6
4 2
0 −
2 −
4 −
6 −
8 0
1 2
3 4
5 6
7 ChannelNumberG034 Figure24. GainError(LSB) GAINERRORvsFREE-AIRTEMPERATURE
8 6
4 2
0 −
2 −
4 −
6 −8−40−25−10 52035506580Free-AirTemperature(°C) Figure25. 95110125 G035 GainError(LSB) GAINERRORvsPOSITIVEHIGH-VOLTAGESUPPLY
8 6
4 2
0 −
2 −
4 −
6 −
8 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G036 Figure26. Copyright©2011,TexasInstrumentsIncorporated 13 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. SNRvsANALOGSUPPLYVOLTAGE SNRvsSIGNALRANGE 72 72 71.8 71.8 Signal-to-NoiseRatio(dB) Signal-to-NoiseRatio(dB) 71.6 71.6 71.4 71.4 71.2 71.2 71 71 70.8 70.8 70.6 70.6 70.4 70.4 70.2 70.2 70 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD
(V)G037 70±2.5V ±5V ±10V 0−5V SignalRange 0−10V G038 Figure27. Figure28. Signal-to-NoiseRatio(dB) SNRvsREFERENCEVOLTAGE 72 71.8 71.6 71.4 71.2 71 70.8 70.6 70.4 70.2 70
2 2.2 2.4 2.6 2.8
3 Reference
Voltage(V)G039 Figure29. Signal-to-NoiseRatio(dB) SNRvsCHANNELNUMBER 72 71.8 71.6 71.4 71.2 71 70.8 70.6 70.4 70.2 70
0 1
2 3
4 5
6 7 Channel
NumberG040 Figure30. Signal-to-NoiseRatio(dB) SNRvsFREE-AIRTEMPERATURE 7271.871.671.471.2 7170.870.670.470.2 70−40−25−105203550658095Free-AirTemperature(°C) Figure31. 110125 G041 Signal-to-NoiseRatio(dB) SNRvsPOSITIVEHIGH-VOLTAGESUPPLY 72 71.8 71.6 71.4 71.2 71 70.8 70.6 70.4 70.2 70 2.5
5 7.5 10 12.5 15 HVDD,
PositiveHigh-VoltageSupply(V)G042 Figure32. 14 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. SNRvsINPUTFREQUENCY SINADvsANALOGSUPPLYVOLTAGE 72 72 Signal-to-NoiseandDistortion(dB) 71.8 71.8 Signal-to-NoiseRatio(dB) 71.6 71.6 71.4 71.4 71.2 71.2 71 71 70.8 70.8 70.6 70.6 70.4 70.4 70.2 70.2 70
0 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G043 70 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G044 Figure33. Figure34. Signal-to-NoiseandDistortion(dB) 7271.871.671.471.2 7170.870.670.470.2 70±2.5V SINADvsSIGNALRANGE ±5V ±10V SignalRange Figure35. 0−5V 0−10V G045 Signal-to-NoiseandDistortion(dB) SINADvsREFERENCEVOLTAGE 72 71.5 71 70.5 70 69.5 69 68.5 68
2 2.2 2.4 2.6 2.8
3 ReferenceVoltage(V)G046 Figure36. Signal-to-NoiseandDistortion(dB) SINADvsCHANNELNUMBER 72 71.5 71 70.5 70 69.5 69 68.5 68
0 1
2 3
4 5
6 7 ChannelNumberG047 Figure37. Signal-to-NoiseandDistortion(dB) SINADvsFREE-AIRTEMPERATURE 72 71.5 71 70.5 70 69.5 69 68.5 68−40−25−10 52035506580Free-AirTemperature(dB) Figure38. 95110125 G048 Copyright©2011,TexasInstrumentsIncorporated 15 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. SINADvsPOSITIVEHIGH-VOLTAGESUPPLY SINADvsINPUTFREQUENCY 72 72 Signal-to-NoiseandDistortion(dB) Signal-to-NoiseandDistortion(dB) 71.5 71.5 71 71 70.5 70.5 70 70 69.5 69.5 69 69 68.5 68.5 68 2.5
5 7.5 10 12.5 15 HVDD,
PositiveHigh-VoltageSupply(V)G049 Figure39. 680 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G050 Figure40. TotalHarmonicDistortion(dB) THDvsANALOGSUPPLYVOLTAGE −82 −82.5 −83 −83.5 −84 −84.5 −85 −85.5 −86 −86.5 −87 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD
(V)G051 Figure41. TotalHarmonicDistortion(dB) −75−76−77−78−79−80−81−82−83−84−85−86−87 ±2.5V THDvsSIGNALRANGE ±5V ±10V SignalRange Figure42. 0−5V 0−10V G052 TotalHarmonicDistortion(dB) THDvsREFERENCEVOLTAGE −75 −76 −77 −78 −79 −80 −81 −82 −83 −84 −85 −86 −87
2 2.2 2.4 2.6 2.8
3 Reference
Voltage(V)G053 Figure43. TotalHarmonicDistortion(dB) THDvsCHANNELNUMBER −75 −76 −77 −78 −79 −80 −81 −82 −83 −84 −85 −86 −87
0 1
2 3
4 5
6 7 Channel
NumberG054 Figure44. 16 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. THDvsFREE-AIRTEMPERATURE THDvsPOSITIVEHIGH-VOLTAGESUPPLY −75 −75 −76 TotalHarmonicDistortion(dB) TotalHarmonicDistortion(dB) −77 −77 −78 −79 −79 −80 −81 −81 −82 −83 −83 −84 −85 −85 −86 −87−40−25−10 52035506580Free-AirTemperature(°C) 95110125 G055 −87 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G056 Figure45. Figure46. TotalHarmonicDistortion(dB) −75−76−77−78−79−80−81−82−83−84−85−86−87
0 THDvsINPUTFREQUENCY 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G057 Figure47. Spurious-FreeDynamicRange(dB) SFDRvsANALOGSUPPLYVOLTAGE 88 87.5 87 86.5 86 85.5 85 84.5 84 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD
(V)G058 Figure48. Spurious-FreeDynamicRange(dB) 8887.5 8786.5 8685.5 8584.5 8483.5 8382.5 82±2.5V SFDRvsSIGNALRANGE ±5V ±10V SignalRange Figure49. 0−5V 0−10V G059 Spurious-FreeDynamicRange(dB) SFDRvsREFERENCEVOLTAGE 88 87.5 87 86.5 86 85.5 85 84.5 84 83.5 83 82.5 82
2 2.2 2.4 2.6 2.8
3 Reference
Voltage(V)G060 Figure50. Copyright©2011,TexasInstrumentsIncorporated 17 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. SFDRvsCHANNELNUMBER SFDRvsFREE-AIRTEMPERATURE 88 88 Spurious-FreeDynamicRange(dB) Spurious-FreeDynamicRange(dB) 87.587 8786 86.5 86 85 85.584 8583 84.5 84
0 1
2 3
4 5
6 7 ChannelNumberG061 Figure51. 82−40−25−10 52035506580Free-AirTemperature(°C) Figure52. 95110125 G062 SFDRvsPOSITIVEHIGH-VOLTAGESUPPLY 88 SFDRvsINPUTFREQUENCY 90 Spurious-FreeDynamicRange(dB) Spurious-FreeDynamicRange(dB) 87 89 86 88 85 87 84 86 83 85 82 2.5
5 7.5 10 12.5 15 HVDD,PositiveHigh-VoltageSupply(V)G063 Figure53. 840 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G064 Figure54. CROSSTALKvsINPUTFREQUENCY −70 ANALOGSUPPLYCURRENT(Dynamic)vsANALOGSUPPLYVOLTAGE 3.5 −80 MemoryCrosstalk
3 AVDDDynamicCurrent(mA) Crosstalk(dB) −90 2.5 IsolationCrosstalk −100
2 −110−120
0 15 30 45 60 75 90105 fIN,InputFrequency(kHz) G065 Figure55. 1.5 HVDD=15V HVSS=−15V
1 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G001 Figure56. 18 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. ANALOGSUPPLYCURRENT(Dynamic)vsFREE-AIRTEMPERATURE ANALOGSUPPLYCURRENT(Dynamic)vsSAMPLERATE 2.4HVDD=15VHVSS=−15V 3.5HVDD=15V 3HVSS=−15V 2.352.5 AVDDDynamicCurrent(mA) AVDDDynamicCurrent(mA) 22.3 1.5 2.2510.5 2.2−40−25−10 52035506580Free-AirTemperature(°C) Figure57. 95110125 G002
0 0 0.2 0.4 0.6 0.8
1 fSAMPLE,SampleRate(MSPS) G003 Figure58. ANALOGSUPPLYCURRENT(Static)vsANALOGSUPPLYVOLTAGE 1.8HVDD=15VHVSS=−15V 1.6 POSITIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsANALOGSUPPLYVOLTAGE 0.5 0.45 0.4 HVDDDynamicCurrent(mA) AVDDStaticCurrent(mA) 1.4 0.35 0.31.2 0.25
1 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G004 Figure59. 0.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G005 Figure60. HVDDDynamicCurrent(mA) POSITIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsFREE-AIRTEMPERATURE 0.5HVDD=15V 0.45HVSS=−15V 0.4 0.35 0.3 0.25 HVDDDynamicCurrent(mA) POSITIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsPOSITIVEHIGH-VOLTAGESUPPLY 1HVDD=15VHVSS=−15V 0.8 0.6 0.4 0.2 0.2−40−25−10 52035506580Free-AirTemperature(°C) Figure61. 95110125 G006
0 5
7 9 11 13 15 HVDD,PositiveHigh-VoltageSupply(V)G007 Figure62. Copyright©2011,TexasInstrumentsIncorporated 19 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. POSITIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsSAMPLERATE NEGATIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsANALOGSUPPLYVOLTAGE 0.5HVDD=15VHVSS=−15V 0.4 −0.2−0.25 HVSSDynamicCurrent(mA) HVDDDynamicCurrent(mA) −0.30.3 −0.35 0.2−0.4 0.1 −0.45
0 0 0.2 0.4 0.6 0.8
1 fSAMPLE,SampleRate(MSPS) G008 Figure63. −0.5 2.7 3.2 3.7 4.2 4.7 5.2 5.7 AVDD(V)G009 Figure64. HVSSDynamicCurrent(mA) NEGATIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsFREE-AIRTEMPERATURE −0.3HVDD=15V −0.35 −0.4 −0.45 −0.5−40−25−10 52035506580Free-AirTemperature(°C) Figure65. 95110125 G010 HVSSDynamicCurrent(mA) NEGATIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsNEGATIVEHIGH-VOLTAGESUPPLY
0 −0.05 −0.1 −0.15 −0.2 −0.25 −0.3 −0.35 −0.4 −0.45 −0.5 −15 −12 −
9 −
6 −
3 0 HVSS,
NegativeHigh-VoltageSupply(V)G011 Figure66. HVSSDynamicCurrent(mA) NEGATIVEHIGH-VOLTAGESUPPLYCURRENT(Dynamic)vsSAMPLERATE 0HVDD=15VHVSS=−15V −0.1 −0.2 −0.3 −0.4 −0.5
0 0.2 0.4 0.6 0.8
1 fSAMPLE,SampleRate(MSPS) G012 Figure67. DifferentialNonlinearity(LSB) 1.61.41.2 10.80.60.40.2 0−0.2−0.4−0.6−0.8 −10 DNL 5121024153620482560307235844095ADCOutputCode(LSB)G066 Figure68. 20 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 IntegralNonlinearity(LSB)ADC,OutputCode Amplitude(dB) TYPICALCHARACTERISTICS(continued) AtTA=+25°C,internalreference=2.5V,channel0,range=±2.5V,AVDD=2.7V,DVDD=1.8V,HVDD=10V,HVSS=–10V,andfSAMPLE=1MSPS,unlessotherwisenoted. INL SPECTRALRESPONSE 1.51.20.90.60.3 0−0.3−0.6−0.9−1.2−1.5
0 5121024153620482560307235844095ADCOutputCode(LSB)G067 0−10−20−30−40−50−60−70−80−90−100−110−120−130
0 50100150200250300350400450500 fIN,InputFrequency(kHz) G068 Figure69. Figure70. TEMPERATURESENSOROUTPUTvsFREE-AIRTEMPERATURE 3900 3875 3850 3825 3800 3775 3750 3725 3700−40−25−10 52035506580Free-AirTemperature(°C) Figure71. 95110125 G069 Copyright©2011,TexasInstrumentsIncorporated 21 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 OVERVIEW TheADS8634andADS8638are12-bit,4-and8-channeldevices,respectively.TheADS8634/8featuresoftware-selectablebipolarandunipolarranges,aninternalreferencewithanoptiontouseanexternalreference,andaninternaltemperaturesensor.Independentpower-downcontrolfortheinternalreferenceandtemperaturesensorblocksallowsforoptimalpowerbasedonapplication.Thefollowingsectionsdescribetheindividualblocksandoperation. MULTIPLEXERANDANALOGINPUT TheADS8634/8featuresingleendedinputswithgroundsenseanda4-/8-channel,single-polemultiplexer,respectively.TheADCsamplesthedifferencevoltagebetweenanaloginputpinsAINxandthegroundsensepinAINGND.TheADS8634/8canscantheseanaloginputsineithermanualorauto-scanmode.Inmanualmode,thechannelisselectedforeverysampleviaaregisterwrite;inauto-scanmode,thechannelnumberisincrementedautomaticallyoneveryCSfallingedgeafterthepresentchannelissampled.Itispossibletoselecttheanaloginputsforanautoscanwithregistersettings.Thedevicesautomaticallyscanonlytheselectedanaloginputsinascendingorder. TheADS8634/8offermultiplesoftware-programmableranges±10V,±5V,±2.5V,0Vto5V,and0Vto10Vwitha2.5Vreference.Anyoftheserangescanbeassignedtoanyanaloginput(forinstance,±10VcanbeassignedtoAIN1,±2.5VtoAIN2,0Vto10VcanbeassignedtoAIN3,andsoon).Duringascan(eitherautoormanual),theprogrammedsignalrangeisassignedtotheselectedchannel.Therangeselection,however,canbetemporarilyoverriddenusingtheDINlineforaparticularscan.Thisfeatureisusefulforzoomingintoanarrowrangewhenneeded.RefertoTable11forconfigurationregistersettings. 22 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 Figure72showselectrostaticdischarge(ESD)diodesconnectedtotheHVDDandHVSSsupplies.Makesurethesediodesdonotturnonbykeepingtheanaloginputswithinthespecifiedrange. HVDD AIN0 HVSSHVDD TemperatureSensor AIN1 HVSS SARADC AIN3/7AINGND HVDD HVSSHVDD HVSS Figure72.AnalogInputs Copyright©2011,TexasInstrumentsIncorporated 23 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 TheADS8634/8samplethevoltagedifference(VAINx–VAINGND)betweentheselectedanaloginputchannelandtheAINGNDpin.TheADS8634/8allowa±0.2VrangeonAINGND.Thisfeatureisusefulinmodularsystemswherethesensor/signalconditioningblockisremovedfromtheADCandwhentherecouldbeadifferenceinthe groundpotentialofthesensor/signalcondionerfromtheADCground.Insuchcases,itismendedtorun separatewiresfromtheAINGNDterminalofthedevicetothesensor/signalconditionerground. REFERENCE TheADS8634/8measuretheanaloginputsignalsrelativetothevoltagereferenceusingeitheraninternalprecision2.5Vvoltagereference(Figure73)oranexternalvoltagereference(Figure74).Binary-weightedcapacitorsareswitchedontothereferenceterminalduringconversion.TheswitchingfrequencyisthesameastheSCLKfrequency.Whetheritisaninternalorexternalreference,besuretodecoupletheREFterminaltoREFGNDwitha10µFcapacitor.PlacethecapacitorclosetotheREFPandREFGNDpins. AVDDAGND InternalReference 10F REFREFGND ADC ConfigurationRegister Figure73.OperationUsingTheInternalReference(RefertoTable11formoredetailsontheconfigurationregistersettings) AVDDAGND AVDDPlane InternalReference REF30/50xx AGNDPlane REF1FREFGND ADC ConfigigurationRegister Figure74.OperationUsinganExternalReference(RefertoTable11formoredetailsontheconfigigurationregistersettings) 24 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 Thesedevicesallowtheuseofanexternalreferenceintherangeof2.0Vto3.0V.Thenominalinputranges±10V,±5V,±2.5V,0Vto5V,and0Vto10Vassumea2.5Vreference;adifferentreferencevoltagescalesthefull-scalerangesproportionately.Forexample,ifa3.0Vreferenceisusedandthe±10Vrangeisselected,theactualinputrangeisscaledby(3.0/2.5)forafull-scalerangeof±12V. Theinternalreferencecanbeenabled/disabledthroughtheconfigurationregister.Thereferenceblockispowereddownwhentheinternalreferenceisdisabled.Ensurethattheinternalreferenceisdisabledwhentheexternalreferenceisconnected.Theexternalreferenceisthedefaultselectionafterpower-onorreset. TEMPERATURESENSOR TheADS8634/8featureanon-chiptemperaturesensorasshowninFigure75.Thedevicetemperaturecanbereadatanytimeduringascan,eitherinautoormanualmode.Therearethreeregistersassociatedwiththetemperaturesensoroperation.Thetemperaturesensorcanbeenabled/disabledthroughtheAux-Configconfigurationregister.Disablingthetemperaturesensorpowersdownthetemperatureblock.Itisnecessarytoenable(powerup)thetemperaturesensoratleastonecyclebeforethedevicetemperaturesensorisselectedwiththechannelsequencingcontrolregisters(manual/auto).ThisselectionoverridestheinputchannelscansequenceandrangeselectionandconnectstheADCinputtoaninternaltemperaturesensor.Thetemperaturesensormustbedeselectedwithchannelsequencingcontrolregisters(manual/auto)toresumenormalscanning.Incaseofauto-sequencing,thedevicestartsscanningfromwhereitleftoffbeforethetemperaturemeasurement.Thetemperaturesensorisdisabledbydefaultafterpower-onorreset. AVDDAGND ChSeqControlReg ConfigReg AIN0AIN1AIN2 TempSensor ADC AIN3/7AINGND Figure75.ReadingtheADS8634/8Temperature(RefertoTable11formoredetailsonconfigurationregistersettings) Thetemperaturesensortransferfunctionfollowsastraightline,asshowninEquation1: OutputCode=mREF×DeviceTemperaturein°C+CREF
(1) Equation1canbere-writtenasEquation2:DeviceTemperaturein°C=(OutputCode–CREF)/mREF where: mREF=theslope, andCREF=theoffset(inADCoutputcode)ofthetemperaturesensortransferfunction
(2) BothmREFandCREFchangewiththereferencevoltage.TheinitialvaluesofmREFandCREFata2.5Vreferenceare:mREF_2.5=0.47andCREF_2.5=3777.2 Copyright©2011,TexasInstrumentsIncorporated 25 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ValuesofmREFandCREFforanyreferencevoltageotherthan2.5VcanbecalculatedusingEquation3andEquation4: mREF=mREF_2.5×2.5/VREF
(3) CREF=(CREF_2.5–3584)×2.5/VREF+3584
(4) Forexample,ata2Vreference:mREF_2=0.47×2.5/2=0.59andCREF_2=(3777.2–3584)×2.5/2+3584=3825.5 Forthereferencevoltageused,Equation2canberewrittedusingmREFandCREFascalculatedinEquation3andEquation4. Table3canbeusedasquickreferencefortemperaturesensortransferfunctionattypicalreferencevalues. Table3.TemperatureSensorTransferFunctionatTypicalReferenceValues REFERENCEVOLTAGE(V)22.53 TRANSFERFUNCTIONDevicetemperaturein°C=(outputcode–3825.5)/0.59Devicetemperaturein°C=(outputcode–3777.2)/0.47Devicetemperaturein°C=(outputcode–3745.0)/0.39 DATAFORMAT TheADS8634/8output12-bitsofADCconversionresultsinbinaryformat(MSBfirst)forallranges,asshowninTable4.Figure76showstheADCtransferfunctionforbipolarsignalranges.TheunipolarrangeoutputisshowninTable5andFigure77showsthetransferfunction. Table4.BipolarRangeIdealOutputCodes
(1) ±10VRANGE(V)≥10×(211–1)/211
(2) 10/211 0–10/211≤–10×(211–1)/211 INPUTSIGNAL(AINx–AINGND) ±5VRANGE(V)≥5×(211–1)/211 5/211 0–5/211≤–5×(211–1)/211 ±2.5VRANGE(V)≥2.5×(211–1)/211 2.5/211 0–2.5/211≤–2.5×(211–1)/211 IDEALOUTPUTCODE FFFh801h800h7FFh000h
(1)Excludesnoise,offsetandgainerrors.
(2)LSBsizeforthebipolarranges=positive(ornegative)full-scale/211.TheADS8634/8offer12-bitresolutionacrosstheentirerangefrom positivefull-scaletonegativefull-scale;inotherwords,theresolutionforhalfrangefrom'0'topositive(ornegative)full-scaleis11bits.Forexample,a1LSBfora±10Vrangeis10/211. Table5.UnipolarRangeIdealOutputCodes
(1) INPUTSIGNAL(AINx–AINGND) 0VTO10VRANGE(V)≥10×(212–1)/21210/212<10/212 0VTO5VRANGE(V)≥5×(212–1)/2125/212<5/212 IDEALOUTPUTCODEFFFh001h000h
(1)Excludesnoise,offsetandgainerrors. 26 Copyright©2011,TexasInstrumentsIncorporated FFFh ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 ADCCode 800h 001h NegativeFSR+1LSB 0AnalogInput(AINx PositiveFSR1LSB AINGND) Figure76.TransferFunctionforBipolarSignalRanges FFFh ADCCode 800h 001h 1LSB FSR/2AnalogInput(AINx FSR–1LSBAINGND) Figure77.TransferFunctionforUnipolarSignalRanges Copyright©2011,TexasInstrumentsIncorporated 27 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 AL_PD:USER-CONFIGURABLEPIN TheADS8634/8featureauser-configurableAL_PDpin.Thispincaneitherbeconfiguredasanalarmoutput(AL)orasapower-downcontrolpin(PD).RefertothePage0,RegisterDescriptionsfortheADS8638andPage0,RegisterDescriptionsfortheADS8634sectionsfordetails. Whenprogrammedasanalarmoutput,anactive-highalarmisflaggedonthispinifthereisahighorlowalarmonanychannel.TheAlarmFunctionalitysectiondescribesthepindetails. WhenprogrammedasPD,theAL_PDpinfunctionsasanactive-lowpower-downinputpin.Poweringdownthroughthispinisasynchronous.Thedevicespowerdownimmediatelyafterthepingoeslow.ThePower-DownFunctionalitysectiondescribesthepindetails. ThispinisconfiguredasaPDinputbydefaultafterpower-onorreset. AlarmFunctionality TheADS8634/8outputanactive-highalarmontheAL_PDpinwhenitisprogrammedasanAL.ALissynchronousandchangesitsstateonthe16thSCLKrisingedge.AhighlevelonALindicatesthereisanactivealarmononeormorechannels.Thispincanbewiredtointerruptthehostinput.Whenanalarminterruptisreceived,thealarmflagregistersarereadtodeterminewhichchannelshaveanalarm. TheADS8634/8featureindependently-programmablealarmsforeachchannel.Therearetwoalarmsperchannel(lowandhighalarm)andeachalarmthresholdhasaseparatehysteresissetting. TheADS8634/8setahighalarmwhenthedigitaloutputforaparticularchannelexceedsthehighalarmupperlimit(highalarmthresholdT+hysteresisH).Thealarmresetswhenthedigitaloutputforthechannelislessthanorequaltothehighalarmlowerlimit(highalarmT–H).ThisfunctionisshowninFigure78. H_ALARMOn Alarm H_ALARMOff (T–H)(T+H+1)ADCOutputNOTE:T=alarmthresholdandH=hysteresis. Figure78.High-AlarmHysteresis Similarly,theloweralarmistriggeredwhenthedigitaloutputforaparticularchannelfallsbelowthelowalarmlowerlimit(lowalarmthresholdT–H).Thealarmresetswhenthedigitaloutputforthechannelisgreaterthanorequaltothelowalarmhigherlimit(lowalarmT+H).ThisfunctionisshowninFigure79. L_ALARMOn L_ALARMOff Alarm (T–H–1)(T+H) ADCOutput NOTE:T=alarmthresholdandH=hysteresis. Figure79.Low-AlarmHysteresis 28 Copyright©2011,TexasInstrumentsIncorporated ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 Figure80showsafunctionalblockdiagramforasingle-channelalarm.Foreachhighandlowalarmtherearetwoflags:ActiveAlarmFlagandTrippedAlarmFlag;refertotheAlarmFlagsfortheADS8638(Read-Only)andAlarmFlagsfortheADS8634(Read-Only)sectionsformoredetails.Theactivealarmflagistriggeredwhenanalarmconditionisencounteredforaparticularchannel;theactivealarmflagresetswhenthealarmshutsoff.Atrippedalarmflagsetsanalarmconditioninthesamemannerasitdoesforanactivealarmflag;however,itremainslatchedandresetsonlywhentheappropriatealarmflagregisterisread. AllChannelH/LAlarms AlarmThresholdChanneln+/- HysteresisChanneln ADCOutputChanneln ADC + 16thSCLK SQRQ AL_PD ProgrammedasAlarmOutput ActiveAlarmFlagChanneln TrippedAlarmFlagChanneln AlarmFlagRead SDO Figure80.AlarmFunctionality Power-DownFunctionality TheADS8634/8featureapower-down/upcontrolthroughtheprogrammableAL_PDpinorthechannelsequencingcontrolregisters;seetheChannelSequencingControlRegistersfortheADS8638andChannelSequencingControlRegistersfortheADS8634sectionsformoredetails.ThisfeatureisextremelyusefulforsavingpowerwhilerunningtheADS8634/8ataslowerspeed,orforacquiringdataatfull-speedinburstsandthenwaitinginapower-downstateforthenextacquisitionstartevent.Figure81throughFigure84describeentrytoandexitfromthepower-downstate. TheAL_PDpincanbeprogrammedasapower-downcontrolpin.TheAL_PDpin,whenprogrammedasPD,isshowninFigure81.AlowonAL_PDpowersdownthedeviceimmediately;thisactionisasynchronousoperation.DataonDOUTarenotvalidwhenthedeviceisinapower-downstate. AL_PD ProgrammedasPD Power-DownStateActive(Internal) Power-Down DOUT Validdataterminatesonpowerdown. Figure81.Power-DownUsingtheAL_PDPin Copyright©2011,TexasInstrumentsIncorporated 29 ADS8634ADS8638 ZHCS362A–MAY2011–REVISEDAUGUST2011 AhighlevelonAL_PDactsasapower-uprequestandthepower-upsequencebeginsonthenextCSfalling edge.Thedeviceisactiveaftertd(PWRUP).Thefirstvalidacquisitioninitiatesinthefirstdataframe(withaCSfallingedge)afterapower-updelay.Thefirstvaliddataarepresentedintheseconddataframeafterthedevice attainsanactivestate,asshowninFigure82. CSSCLK 1216 1216 1216 1216 AL_PDProgrammedasPD Power-DownState(Internal) Power-Down Td(PWRUP)Power-UpDelay Active DOUT InvalidData InvalidData InvalidData ValidData Figure82.Power-UpViatheAL_PDPin ValidData Thepower-down/upoperationcanalsobecontrolledwithregistersettings.SeetheChannelSequencingControlRegistersfortheADS8638andChannelSequencingControlRegistersfortheADS8634sectionsfordetails.Figure83
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