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TDC1011-Q1
ZHCSDU8–JULY2015
TDC1011-Q1面向液位感测、浓度感测应用的单通道超声波感测模拟前端(AFE)
1特性
•1符合汽车级AEC-Q100标准(TDC1011-Q1)•测量范围：高达8ms•工作电流：1.8µA(2SPS)•发送器通道TX
–支持单传感器应用–可编程激励：31.25kHz至4MHz，多达31个
脉冲•接收器通道RX
–STOP逐周期抖动：50psRMS–低噪声、可编程增益放大器–可访问外部滤波器的信号链设计–针对回声质检的可编程阈值比较器–针对较长TOF测量的可编程低功耗模式•温度测量–2个PT1000/500RTD接口–RTD间的匹配精度为0.02°CRMS•工作温度范围：-40°C至125°C
2应用
•不同材料箱中的各项测量：–液位–液体鉴别/浓度
3说明
TDC1011是一款全集成超声波感测模拟前端(AFE)，常用于汽车、工业、医疗和消费品市场中的液位、液体鉴别/浓度以及接近传感/远距感测应用。
与MSP430/C2000MCU、电源、无线网络和源代码配套使用时，TI可提供完整的超声波感测解决方案。
TI的超声波AFE可编程且具有灵活性，可适应广泛的应用和终端设备。
TDC10111可针对多种发射脉冲和频率、增益和信号阈值进行配置，以便在多种传感器频率（31.25kHz至4MHz）和Q系数下使用。
同样，接收路径可编程设定，因此在更远的距离/更大的箱体尺寸范围内也能够检测到通过多种介质传播的超声波。
TDC1011可选择不同的工作模式，并且针对低功耗进行了优化，这使得它成为电池供电应用的理想选择。
低噪声放大器和比较器产生的抖动极低，可实现皮秒级分辨率和精度。
器件型号TDC1011-Q1 器件信息
(1) 封装TSSOP(PW-28) 封装尺寸（标称值）9.70mmx4.40mm
(1)要了解所有可用封装，请见数据表末尾的可订购产品附录。
1 AnIMPORTANTNOTICEattheendofthisdatasheetaddressesavailability,warranty,changes,useinsafety-criticalapplications, intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA. EnglishDataSheet:SNAS670 TDC1011-Q1 ZHCSDU8–JULY2015 目录 1特性..........................................................................12应用..........................................................................13说明..........................................................................14修订历史记录...........................................................25PinConfigurationandFunctions.........................36Specifications.........................................................4 6.1AbsoluteMaximumRatings......................................46.2ESDRatings............................................................46.3mendedOperatingConditions.......................46.4ThermalInformation..................................................46.5ElectricalCharacteristics...........................................56.6TimingRequirements................................................76.7SwitchingCharacteristics..........................................76.8TypicalCharacteristics..............................................87ParameterMeasurementInformation................108DetailedDescription............................................118.1Overview.................................................................118.2FunctionalBlockDiagram.......................................11 8.3FeatureDescription.................................................128.4DeviceFunctionDescription...................................198.5Programming..........................................................288.6RegisterMaps.........................................................309ApplicationandImplementation........................369.1ApplicationInformation............................................369.2TypicalApplications................................................3610PowerSupplymendations.....................4111Layout...................................................................4211.1LayoutGuidelines.................................................4211.2LayoutExample....................................................4212器件和文档支持.....................................................4312.1器件支持................................................................4312.2社区资源................................................................4312.3商标.......................................................................4312.4静电放电警告.........................................................4312.5Glossary................................................................4313机械、封装和可订购信息.......................................43 4修订历史记录 日期2015年7月 修订版本* 注释首次发布。
2 Copyright©2015,TexasInstrumentsIncorporated 5PinConfigurationandFunctions TSSOP(PW)28Pin TopView NC1RX2VCOM3LNAOUT4PGAIN5PGAOUT6COMPIN7RTD18RTD29RREF10RES11ERRB12START13STOP14 TDC1011 28TX27NC26GND25CLKIN24VDD23VDD22VIO21SDO20SDI19CSB18SCLK17RESET16TRIGGER15EN TDC1011-Q1 ZHCSDU8–JULY2015 PINNAMENCRXVCOMLNAOUTPGAINPGAOUTCOMPINRTD1RTD2RREFRESERRBSTARTSTOPENTRIGGERRESETSCLKCSBSDISDOVIOVDD CLKINGNDNCTX PinFunctions NO.12345678910111213141516171819202122 23,24 25262728 TYPE
(1) IPOIOIOOOIOOOIIIIIIOPP IG
O DESCRIPTION NoConnect(leavefloating)ReceiveinputmonmodevoltagebiasLownoiseamplifieroutput(foracdecouplingcapacitor)ProgrammablegainamplifierinputProgrammablegainamplifieroutputEchoqualificationandzero-crossingdetectorinputResistancetemperaturedetectorchannel1Resistancetemperaturedetectorchannel2ReferenceresistorfortemperaturemeasurementReserved(connecttoGND)Errorflag(opendrain)StartpulseoutputpulseoutputEnable(activehigh;whenlowtheTDC1011isinSLEEPmode)TriggerinputReset(activehigh)SerialclockfortheSPIinterfaceChipselectfortheSPIinterface(activelow)SerialdatainputfortheSPIinterfaceSerialdataoutputfortheSPIinterfacePositiveI/OsupplyPositivesupply;allVDDsupplypinsmustbeconnectedtothesupply.Placea100-nFbypasscapacitortogroundincloseproximitytothepin.ClockinputNegativesupplyNoConnect(leavefloating)Transmitoutput
(1)G=Ground,I=Input,O=Output,P=Power Copyright©2015,TexasInstrumentsIncorporated
3 TDC1011-Q1 ZHCSDU8–JULY2015 6Specifications 6.1AbsoluteMaximumRatings Overoperatingfree-airtemperaturerange(unlessotherwisenoted)
(1)(2) VDD Analogsupplyvoltage,VDDpins VIO I/Osupplyvoltage(VIOmustalwaysbelowerthanorequaltoVDDsupply) VI Voltageonanyanaloginputpin
(3) VI Voltageonanydigitalinputpin
(3) II Inputcurrentatanypin TJ Operatingjunctiontemperature Tstg Storagetemperaturerange MIN MAX UNIT –0.3 6.0
V –0.3 6.0
V –0.3 VDD+0.3
V –0.3 VIO+0.3
V 5 mA –40 125 °
C –65 150 °
C
(1)StressesbeyondthoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratingsonly,whichdonotimplyfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedundermendedOperatingConditions.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability.
(2)Allvoltagesarewithrespecttoground,unlessotherwisespecified.
(3)Whentheinputvoltageatapinexceedsthepowersupplies,thecurrentatthatpinmustnotexceed5mAandthevoltage(VI)atthat pinmustnotexceed6.0V. 6.2ESDRatings V(ESD)Electrostaticdischarge Human-bodymodel(HBM),perAECA100-002
(1) Charged-devicemodel(CDM),perAECQ100-011 Allpins Cornerpins(1,14,15and28) VALUE±2000±500 ±750
(1)AECQ100-002indicatesHBMstressingisdoneinordancewiththeANSI/ESDA/JEDECJS-001specification. UNITV 6.3mendedOperatingConditions Overoperatingfree-airtemperaturerange(unlessotherwisenoted) VDDVIOVIVIƒCLKINTJ Analogsupplyvoltage,VDDpinsDigitalsupplyvoltage,(VIOmustalwaysbelowerthanorequaltoVDDsupply)VoltageonanyanaloginputpinVoltageonanydigitalinputpinOperatingfrequencyOperatingjunctiontemperature MIN2.71.8GNDGND0.06–40 MAX5.5VDDVDDVIO16125 UNITVVVV MHz°
C 6.4ThermalInformation
(1) THERMALMETRIC RθJARθ)RθJBψJTψJB Junction-to-ambientthermalresistanceJunction-to-case)thermalresistanceJunction-to-boardthermalresistancecharacterizationparameterJunction-to-boardcharacterizationparameter TDC1011TSSOPPW(28PINS) 83.5 29.9 40.8 2.4 40.3 UNIT°C/W
(1)Formoreinformationabouttraditionalandnewthermalmetrics,seetheICPackageThermalMetricsapplicationreport,SPRA953.
4 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 6.5ElectricalCharacteristics Theelectricalratingsspecifiedinthissectionapplytoallspecificationsinthisdocument,unlessotherwisenoted.Thesespecificationsareinterpretedasconditionsthatdonotdegradethedeviceparametricorfunctionalspecificationsforthelifeoftheproductcontainingit.TA=25°
C,VDD=VIO=3.7V,VCOM=VCM=VDD/2,CVCOM=10nF(unlessotherwisenoted). PARAMETER TESTCONDITIONS MIN TYP MAXUNIT TRANSMITTERSIGNALPATH(TX) VOUT(TX) Outputvoltageswing ƒout=1MHz,RL=75ΩtoVCM HIGHLOW VDD–0.32
V 0.32
V IOUT(TX) Outputdrivecurrent ƒout=1MHz,RL=75ΩtoVCM 22 mARMS ƒOUT(TX) OutputTXfrequency ƒCLKIN=8MHz,divide-by-2(programmable;seeTransmitterSignalPath)
4 MHz RECEIVERSIGNALPATH(RX) ΔtSTOP STOPcycle-to-cyclejitter LNAcapacitivefeedback,GPGA=6dB,ƒIN=1MHz,VIN=100mVPP,CVCOM=1µFandFigure14 50 psRMS LNA GLNA LNAgain Capacitivefeedback,CIN=300pF,ƒIN=1MHz,RL=100kΩtoVCM,CVCOM=1µ
F 20 dB enLNA LNAinputreferrednoisedensity Capacitivefeedback,CIN=300pF,ƒ=1MHz,VDD=3.1V,VIN=VCM,RL=∞,CVCOM=1µ
F 2 nV/√Hz VIN(LNA) Inputvoltagerange Resistivefeedback,RL=1kΩtoVCM,CVCOM=1µ
F HIGHLOW VCM+(VCM–0.24)/(GLNA)
V VCM–(VCM–0.24)/(GLNA)
V VOUT(LNA) Outputvoltagerange Resistivefeedback,RL=1kΩtoVCM,CVCOM=1µ
F HIGHLOW VDD–0.24
V GND+0.24
V SRLNA Slewrate
(1) Resistivefeedback,RL=1kΩtoVCM,100mVstep,CVCOM=1µ
F 9 V/μs BWLNA –3-dBbandwidth Capacitivefeedback,CIN=300pF,RL=100kΩtoVCM,CVCOM=1µ
F 5 MHz VOS(LNA) LNAinputoffsetvoltage Resistivemode,VIN=VCM,RL=∞ ±320 µ
V VCOM VCOM VCOMoutputvoltageVCOMoutputerror CVCOM=1µ
F VCM
V 0.5% PGA VIN(PGA) PGAinputrange RL=100kΩtoVCM,CL=10pFtoGND HIGHLOW VCM+(VCM–0.06)/(GPGA)
V VCM–(VCM–0.06)/(GPGA)
V GPGAMIN PGAmingain
0 dB GPGAMAX PGAmaxgain DC,RL=∞,CL=10pF 21 dB ΔGPGA PGAgainstepsize
3 dB GE(PGA) PGAgainerror DC,GPGA=0dB,RL=∞,CL=10pF 5% TCGPGA PcoGeAfficgiaeinnttemperatureDC,GPGA=0dB,RL=∞,CL=10pF 170 ppm/°
C enPGA PGAinputreferrednoisedensity GPGA=21dB,ƒ=1MHz,VDD=3.1V,VIN=VCM,RL=∞,CVCOM=1µ
F 3.1 nV/√Hz VOUT(PGA) Outputrange RL=100kΩtoVCM,CL=10pFtoGND HIGHLOW VDD–0.06
V 60 mV BWPGA –3-dbbandwidth GPGA=21dB,RL=100kΩtoVCM,CL=10pF,CVCOM=1µ
F 5 MHz SRPGA Slewrate
(1) GPGA=21dB,RL=100kΩtoVCM,CL=10pF,CVCOM=1µ
F 12.5 V/µs
(1)Theslewrateismeasuredfrom10%to90%andisrepresentedbytheaverageoftherisingandfallingslewrates. Copyright©2015,TexasInstrumentsIncorporated
5 TDC1011-Q1 ZHCSDU8–JULY2015 ElectricalCharacteristics(continued) Theelectricalratingsspecifiedinthissectionapplytoallspecificationsinthisdocument,unlessotherwisenoted.Thesespecificationsareinterpretedasconditionsthatdonotdegradethedeviceparametricorfunctionalspecificationsforthelifeoftheproductcontainingit.TA=25°
C,VDD=VIO=3.7V,VCOM=VCM=VDD/2,CVCOM=10nF(unlessotherwisenoted). PARAMETER TESTCONDITIONS MIN TYP MAXUNIT ZEROCROSSCOMPARATOR VOS(COMP) Inputoffsetvoltage
(2) ReferredtoVCOM ±115 µ
V enCOMPHYSTCOMP Zeroparatorinputreferrednoise
(2) Hysteresis
(2) 1MHzReferredtoVCOM
5 nV/√Hz -10 mV THRESHOLDDETECTOR VTHDET Thresholdlevel ECHO_QUAL_THLD=0h,VCOMreferredECHO_QUAL_THLD=7h,VCOMreferred TEMPERATURESENSORINTERFACE
(3) TERROR Temperature RREF=1kΩ,PT1000range:–40to125°C
(4) measurementuracyRREF=1kΩ,PT1000range:–15°Cto85°C
(4) –35 mV –1.5
V 1 °
C 0.5 °
C Relativeuracy RREF=1kΩ,RRTD1=RRTD2=1.1kΩ 0.02 °CRMS TGE Gainerror 5.8 m°C/°
C POWERSUPPLY Sleep(EN=CLKIN=TRIGGER=low) 0.61 µ
A Continuousreceivemode,LNAandPGA bypassed IDD VDDsupplycurrent Continuousreceivemode,LNAandPGAactive Temp.measurementonly(PT1000mode)
(5) Temp.measurement(PT500mode)
(6) 2.8 3mA 6.2 7.5mA 370 400µ
A 500 540µ
A IIOVcuIOrresnutp(2p)lysleepSleep(EN=CLKIN=TRIGGER=low)
2 nA DIGITALINPUT/OUTPUTCHARACTERISTICS VILItnhpreusthloogldiclow 0.2×VIO
V VIHItnhpreusthloogldichigh 0.8×VIO
V SDOpin,100-μAcurrent 0.2
V SDOpin,1.85-mAcurrent 0.4
V Outputlogiclow STARTandSTOPpins,100-μAcurrent VOL threshold STARTandSTOPpins,1.85-mAcurrent 0.5
V 0.6
V ERRBpin,100-μAcurrent 0.2
V ERRBpin,1.85-mAcurrent 0.4
V SDOpin,100-μAcurrent VIO–0.2
V SDOpin,1.85-mAcurrent VIO–0.6
V VOHOthuretpsuhtollodgichighSTARTandSTOPpins,100-μAcurrentVIO–0.5V STARTandSTOPpins,1.85-mAcurrent VIO–0.6
V ERRBpin,0-µAcurrent VIO–0.2
V IOMAX MaximumoutputcurrentforSDO,STARTandSTOP 1.85 mA
(2)Specifiedbydesign.
(3)Withidealponents.FormoredetailseeTempSensorMeasurementsection.
(4)PT1000RTDapproximateresistance:800Ω≡–52°C,931Ω≡–18°C,1.10kΩ≡26°C,1.33kΩ≡86°Cand1.48kΩ≡125°
C.
(5)Specifiedcurrentsinclude120μAwhichflowsthroughtheRTDsensorinPT1000mode(TEMP_RTD_SEL=0).
(6)Specifiedcurrentsinclude240μAwhichflowsthroughtheRTDsensorinPT500mode(TEMP_RTD_SEL=1).
6 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 6.6TimingRequirements TA=25°
C,VDD=VIO=3.7VandƒSCLK=1MHz(unlessotherwisenoted). MIN ƒSCLK Serialclockfrequency t1 Highperiod,SCLK 16 t2 Lowperiod,SCLK 16 t3 Set-uptime,nCStoSCLK 10 t4 Set-uptime,SDItoSCLK 12 t5 Holdtime,SCLKtoSDI 12 t6 SCLKtransitiontoSDOvalidtime 16 t7 Holdtime,SCLKtransitiontonCSrisingedge 10 t8 nCSinactive 17 t9 Holdtime,SCLKtransitiontonCSfallingedge 10 tr/tf Signalriseandfalltimes
(1) NOM1.8 MAX26
(1)Theslewrateismeasuredfrom10%to90%andisrepresentedbytheaverageoftherisingandfallingslewrates. UNITMHznsnsnsnsnsnsnsnsnsns SCLKCSB t9t3 t2 t1 t7 t4t5t8 D15 D14 D0 t6 90% PriorD1510% tr 90% PriorD110% PriorD0 tf Figure1.SPITimingDiagram 6.7SwitchingCharacteristics TA=25°
C,VDD=VIO=3.7V,ƒCLKIN=8MHz. PARAMETER TESTCONDITIONS START,STOP,ENABLE,RESET,CLOCKIN,TRIGGER,ERR TX_FREQ_DIV=2h,NUM_TX=
1 PWSTARTPulsewidthforSTARTsignalTX_FREQ_DIV=2h,NUM_TX=
2 TX_FREQ_DIV=2h,NUM_TX≥
3 tr/tf START Rise/falltimeforSTARTsignal 20%to80%,20-pFload tr/tfSTOPRise/falltimeforSTOPsignal20%to80%,20-pFload ƒCLKINtr/tfCLKIN MaximumCLKINinputfrequency CLKINinputrise/falltime
(1) 20%to80% tr/tfTRIGtEN_TRIG TRIGGERinputrise/falltime
(1)Enabletotriggerwaittime
(1) 20%to80% tRES_TRIGResettotriggerwaittime
(1) TX_FREQ_DIV=2h(seeTX/RXMeasurementSequencingandTiming)
(1)Specifiedbydesign. MIN TYP MAXUNIT
1 μs
2 μs
3 μs 0.25 ns 0.25 ns 16 MHz 10 ns 10 ns 50 ns 3.05 μs Copyright
©2015,TexasInstrumentsIncorporated
7 TDC1011-Q1 ZHCSDU8–JULY2015 6.8TypicalCharacteristics AtTA=25°C,unlessotherwisenoted. 500 OutputImpedanceMagnitude(||) 400 300 200 100
0 ±100 100 1k VDD=VIO=3.7V 10k 100k Frequency(Hz) CapacitiveFeedbackMode 500 OutputImpedanceMagnitude(|_ 400 300 200 100
0 1M 10M C001 RL=1kΩ ±100 100 1k VDD=VIO=3.7V 10k 100k Frequency(Hz) Gainof21dB 1M 10M C002 RL=1kΩ Figure2.LNAZOUTvsFrequency Input-referredNoise(nV/O,Ì 1098765432105k VDD=VIO=3.1V 50k 500k Frequency(Hz) CapacitiveFeedbackMode 2M C013 RL=∞ Figure3.PGAZOUTvsFrequency 10
9 Input-referredNoise(nV/O,Ì
8 7
6 5
4 3
2 1 05k VDD=VIO=3.7V 50kFrequency(Hz) Gainof21dB 500k 2M C014 RL=∞ Figure4.LNAInput-referredNoisevsFrequency Figure5.PGAInput-referredNoisevsFrequency OutputVoltage(250mV/DIV) OutputVoltage(250mV/DIV) VDD=VIO=3.7VVIN=100mV Time(1 s/DIV) ResistiveFeedbackMode C005 RL=1kΩfIN=100kHz VDD=VIO=3.7VVIN=100mV Time(1 s/DIV) Gainof21dB C006 RL=100kΩfIN=100kHz Figure6.LNAResponse8 Figure7.PGAResponseCopyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 TypicalCharacteristics(continued) AtTA=25°C,unlessotherwisenoted. 30 30 20 20 10 10 Gain(dB)Gain(dB)
0 0 ±10 ±10 ±20 ±20 Count(%)Count(%) ±3010k VDD=VIO=3.7VCIN=300pF 100k 1M Frequency(Hz) CapacitiveFeedbackMode 10M C007 RL=100kΩ Figure8.LNAGainvsFrequency 201816141210 86420 ±3010k VDD=VIO=3.7V 100k 1M Frequency(Hz) Gainof21dB 10M C008 RL=100kΩ Figure9.PGAGainvsFrequency 201816141210 86420 -300-200-100 0100200300-300-200-100 0100200300 Count(%)Count(%) VDD=VIO=5VVIN=100mV 201816141210 86420 Time(ps) LNACapacitiveFeedbackMode (SeeFigure14) C009 PGAGainof6dBfIN=1MHz Count>=10000 Figure10.RXJitterHistogram VDD=VIO=3.7VVIN=100mVTA=25C° Time(ps) LNACapacitiveFeedbackMode (SeeFigure14) C010 PGAGainof6dBfIN=1MHz Count>=10000 Figure11.RXJitterHistogram 201816141210 86420 -300-200-100 0100200300-300-200-100 0100200300 VDD=VIO=3.7VVIN=100mVTA=-40C° Time(ps) LNACapacitiveFeedbackMode (SeeFigure14) C011 PGAGainof6dBfIN=1MHz Count>=10000 Figure12.RXJitterHistrogam VDD=VIO=3.7VVIN=100mVTA=125C° Time(ps) LNACapacitiveFeedbackMode (SeeFigure14) C012 PGAGainof6dBfIN=1MHz Count>=10000 Figure13.RXJitterHistogram Copyright©2015,TexasInstrumentsIncorporated
9 TDC1011-Q1 ZHCSDU8–JULY2015 7ParameterMeasurementInformation INPUT CIN=300pF LNAIN LNAOUTCF1=1nF PGAIN PGAOUT RF1=1N CF2=51pF COMPIN CF3=51pF RF2=5.1N GND VCOM Figure14.ExternalCircuitsforJitterMeasurement 10 Copyright©2015,TexasInstrumentsIncorporated 8DetailedDescription TDC1011-Q1 ZHCSDU8–JULY2015 8.1Overview ThemainfunctionalblocksofTDC1011aretheTransmit(TX)andtheReceive(RX)Channels.Thetransmittersupportsflexiblesettingsfordrivingvariousultrasonictransducers,andthereceiverprovidesconfigurableblockswithawiderangeofsettingsforsignalconditioninginvariousapplications.ThereceivesignalchainconsistsofanLNA(LowNoiseAmplifier),aPGA(ProgrammableGainAmplifier),andtwoparatorsforechoqualificationandSTOPpulsegeneration. AmeasurementcycleisinitiatedwithatriggersignalontheTRIGGERpinofthedevice.Afteratriggersignalisasserted,anoutputpulseisgeneratedontheSTARTpin.ThissignalisusedasthetimereferencetobeginaTOFmeasurement.ThetransmittergeneratesprogrammableTXpulses,synchronoustotherisingedgeoftheSTARTpulse,todriveanultrasonictransducerandgenerateanultrasonicwavethatisshotthroughanacousticmedium.ThereceiverdetectstheultrasoundwavethattraveledthroughthemediumandgeneratesSTOPsignals.Whethertheultrasoundwaveisreceiveddirectlyorfromareflectionwilldependonthesystemconfiguration.TheSTOPsignalsareusedbyanexternalTime-to-DigitalConverter(TDC),whichfunctionsasaveryuratewatch.ThesystemmustincludeaTDCtomeasuretheTOFbasedontheintervalbetweentheSTARTandSTOPpulses.Insomeapplicationswithmedium-rangeuracyrequirements(nsrange),amicrocontrollercanbeusedtomeasuretheTOFduration.Inapplicationswithhigh-rangeuracyrequirements(psrange),TImendsusingtheTDC7200time-to-digitalconvertertomeasuretheTOFduration. Ineachapplication,theTDC1011hastobeconfiguredbyaserialinterface(SPI)forthevariousapplicationspecificparametersthatareexplainedinthefollowingsections. 8.2FunctionalBlockDiagram VDDVDDVIOCLKINENTRIGGERRESETRESERRBSDOSDISCLKCSB TXTx Generator ClockDivider RX ± + LNA PGA +20dB VCOM ±0to21dB VCOM TDC1011 SMControlUnit SerialInterface enable DACThresholdDetect EventManager MUX STARTSTOP MUX Zero-CrossDetectAnalogBiasTemp.Sense RTD1RTD2RREFVCOM COMPINPGAOUTPGAINLNAOUT GND Copyright©2015,TexasInstrumentsIncorporated 11 TDC1011-Q1 ZHCSDU8–JULY2015 8.3FeatureDescription 8.3.1TransmitterSignalPath TheTransmitter(TX)pathconsistsofaClockDividerblockandaTXGeneratorblock.TheclockdividerallowstheTDC1011todividetheclocksourcethatisconnectedtotheCLKINpindowntotheresonantfrequency(ƒR)ofthetransducerused.Theclockdividerallowsdivisionfactorsinpowersof2.ThedivisionfactoroftheclockdividercanbeprogrammedwiththeTX_FREQ_DIVfieldintheCONFIG_0register. TheTXGeneratorblockcandriveatransducerwithaprogrammablenumberofTXpulses.ThefrequencyofthesepulsesisdefinedasƒCLKIN/(2TX_FREQ_DIV+1),andshouldmatchtheƒRofthetransducer.ThenumberofpulsesisconfiguredbyprogrammingtheNUM_TXfieldintheCONFIG_0register. Forexample,forƒCLKIN=8MHzandTX_FREQ_DIV=2h(divideby8),thedividedclockfrequencyis1MHz. Inadditiontotheprogrammablenumberofpulses,theTXGeneratoralsoprovidesoptionstointroducea180⁰pulseshiftatpulsepositionnordampingthelastTXpulse.Insomesituations,dampingcanreducetheringingofthetransducerforveryshortTOFmeasurements.ThesefeaturesarefurtherdescribedintheTRANSMITOperationsectionofthedatasheet. 8.3.2ReceiverSignalPath TheRXsignalpathconsistsofanLNA,PGA,andapairparators.TheLNAandPGAprovidetherequiredamplificationofthereceivesignal.TheamplifiedreceivesignalisfedintoasetparatorswhichgeneratepulsesontheSTOPpinbasedontheprogrammedthresholdlevels.TheblockdiagramforthereceiverpathcanbeseeninFigure15. Ifthe20-dBto41-dBofgainprovidedbytheTDC1011isinsufficient,additionalgaincanbeaddedpriortotheCOMPINpin.Likewise,withastrongreceivedsignal,ifthegainfromtheLNAorPGAisnotneeded,theycanbebypassedandthetransducersignalcanbedirectlyconnectedtotheCOMPINpin. Aband-passfiltercenteredonthetransducer’sresponsecanbeusedbetweeneachstageofthereceiverpathtoreducethenoise;notethattheinputsoftheLNA,PGA,paratorsshouldbebiasedtotheVCOMpin’spotential.paratorsconnectedtotheCOMPINpinareusedforechoqualificationandgenerationofSTOPpulsesthatcorrespondtothezero-crossingsoftheechosignal.TheSTOPpulsesareusedwithaSTARTpulsetocalculatetheTOFoftheechointhemedium. enable VCOM ±LNA+ 20dB TDC1011 VCOM +PGA ±0to21dB MUX DACThresholdDetect EventManager STOP AnalogBiasTemp.SenseZero-CrossDetect RTD1RTD2RREFVCOM COMPINPGAOUTPGAINLNAOUTGND Figure15.TDC1011ReceiverPath 12 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 FeatureDescription(continued) 8.3.3LowNoiseAmplifier(LNA) TheLNAintheTDC1011’sfront-endlimitstheinput-referrednoiseandensurestiminguracyforthegeneratedSTOPpulses.TheLNAisaninvertingamplifierdesignedforaclosed-loopgainof20dBwiththeaidofanexternalinputcapacitororresistor,anditcanbeprogrammedfortwofeedbackconfigurations.Thebandpassconfiguration,referredtoascapacitivefeedbackmode,mustbinedwithaninputcapacitor.Thelowpassconfiguration,referredtoasresistivefeedbackmode,mustbinedwithaninputresistor.Themendedvaluesfortheponentsare300pFand900Ωrespectively. TheLNAcanbeconfiguredincapacitivefeedbackmodefortransducerswithresonantfrequenciesintheorder ofacoupleofMHz.ThisisdonebyclearingtheLNA_FBbitintheTOF_1registerto0.AsshowninFigure16, theexternalcapacitor,CIN,shouldbeplacedbetweenthetransducerandtheinputpin.Thisprovidesanin-bandgainofCIN/CF,whereCFistheon-chip30-pFfeedbackcapacitor.ProvidedthatCIN=300pF,thein-bandgainoftheLNAcircuitis: Gain CIN300pF10 inbandCF30pF
(1) CIN300pFRX CF30pF RF 9N VCOM ±LNA + LNAOUT Figure16.LNACapacitiveFeedbackConfiguration ThecapacitivefeedbackconfigurationoftheLNAhasaband-passfrequencyresponse.Thehigh-passcornerfrequencyissetbytheinternalponentsRF(9kΩ)andCF(30pF),andisapproximately590kHz.Thein-bandgainissetbythecapacitorratioandtheLNA’s50-MHzgain-bandwidthproductsetsthelow-passcornerofthefrequencyresponse.Forexample,anin-bandgainof10resultsinabandpassresponsebetween590kHzand5MHz. TheLNAcanbeconfiguredinresistivefeedbackmodefortransducerswithresonantfrequenciesintheorderofacoupleofhundredsofkHz.ThisisdonebysettingtheLNA_FBbitintheTOF_1registerto1.Inthisconfiguration,theinternalfeedbackcapacitorCFisdisconnected(seeFigure17),andtheDCgainoftheLNAcircuitisdeterminedbytheratiobetweentheinternalfeedbackresistorRF(9kΩ)andanexternalresistorRIN.ForRIN=900Ω,thegainofthecircuitis10. RF 9N RINTransducer900RX ±LNA+ LNAOUT VCOM Figure17.LNAResistiveFeedbackConfiguration TheLNAcanbebypassedanddisabledbywritinga1totheLNA_CTRLbitintheTOF_1register. Copyright©2015,TexasInstrumentsIncorporated 13 TDC1011-Q1 ZHCSDU8–JULY2015 FeatureDescription(continued) 8.3.4ProgrammableGainAmplifier(PGA) ThePGA,showninFigure18,isaninvertingamplifierwithaninputresistanceofRIN=500ΩandaprogrammablefeedbackresistorRFBthatcanbeprogrammedtoseta0-dBto21-dBgainin3-dBsteps.ThiscanbedonebyprogrammingthePGA_GAINfieldintheTOF_1register.ThebandwidthofthePGAisscaledbasedonitsprogrammedgain.ThetypicalbandwidthofthePGAwitha100-kΩloadtoVCManda10-pFcapacitortogroundarelistedinTable1. PGA_GAIN(Hex)0h1h2h3h4h5h6h7h Table1.TypicalPGABandwidth Gain(dB)036912151821 Bandwidth(MHz)19.016.814.412.310.08.26.65.0 ThePGAcanbebypassedanddisabledbywritinga1tothePGA_CTRLbitintheTOF_1register.TheoutputofthePGAshouldnotbeloadeddirectlywithcapacitancesgreaterthan10pF. RFB PGA_INRIN500: PGA_OUT PGA VCOM Figure18.TDC1011ProgrammableGainAmplifier 8.3.5ReceiverFilters ItismendedtoplacetwofiltersintheRXpathtominimizethereceivepathnoiseandobtainmaximumtiminguracy.AsshowninFigure19,onefilterisplacedbetweentheLNAOUTandthePGAINpins,andanotherfilterisplacedbetweenthePGAOUTandtheCOMPINpins. Withanin-bandgainof10,theLNAhasabandwidthof5MHz.Formostapplications,alow-passfilterbetweentheLNAOUTandPGAINpinsissufficient. AsshowninFigure19,thesecondfilterstagecanuseacascadeofalow-passfilter(RF1andCF3)followedbyahigh-passfilter(CF2andRF2)referencedtoVCOM.Designofthefilterisstraightforward.TheRF1andCF2canbechosenfirst.AreasonablesetofvaluesforRF1andCF2couldbe:RF1=1kΩ±10%andCF2=50pF±10%.GiventhecenterfrequencyofinteresttobeƒCandthefilterbandwidthtobeƒB,thevalueofCF3canbecalculatedas:
1 CF32SR ff F1CB
(2) RF2andCF2determinethehigh-passcornerofthefilter.RF2shouldbereferencedtoVCOMtomaintaintheDCbiaslevelatparatorinputduringtheechoreceivetime.ForvaluesofRF2largerthanRF1,therewillbelimitedloadingeffectfromthehigh-passfiltertothelow-passfilterresultinginmoreuratecornerfrequencies. Thechosenvaluesshowninthefigurebelowresultinahigh-passcornerfrequencyofabout600kHzandalow- passcornerfrequencyofabout3MHz. 14 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 plexfilterscanbeused;externalgainiseptableifthesignalamplitudeistoolow.Ifthepass-bandofthefilteriswiderthananoctave,itismendedtouseafilterdesignwhichhaslineargroupdelay. LNAOUTCF1=1nF PGAINPGAOUT RF1=1N CF2=50pF COMPIN CF3=53pF RF2=5N Figure19.Filterfora1-MHzOperationGND VCOM 8.3.6ComparatorsforSTOPPulseGeneration TheSTOPpulsegenerationblockoftheTDC1011containstwoparators(azero-crossdetectandaparator),athresholdsettingDAC,andaneventmanager. Comparatorauto-zeroperiodsuratthebeginningofeveryTOFreceivecycle.Duringtheseperiods,parator’sinputoffsetisstoredinaninternal2.5-pFcapacitor,anditissubtractedfromtheinputsignalduringtheechoprocessingphase.Thedurationofauto-zeroperiodisconfiguredwiththeAUTOZERO_PERIODfieldlocatedintheCLOCK_RATEregister. VCOMCOMPIN ZeroCrossDetect± + ECHO_QUAL_THLD +DAC ± VTHLD ThresholdDetect ± + RECEIVE_MODENUM_RX EventManager STOP Figure20.STOPPulseGenerationCircuit 8.3.6.1ThresholdDetectorandDAC ThethresholdparatorinFigureparestheechoamplitudewithaprogrammablethresholdlevel(VTHLD)controlledbyaDAC.TheDACvoltageissetbytheECHO_QUAL_THLDfieldinregisterCONFIG_3andprovides8programmablethresholdlevels,VTHLD.ThetypicallevelsaresummarizedinTable2: ECHO_QUAL_THLDTypicalVTHLD(mV) Table2.EchoQualificationThresholdLevels 0h 1h 2h 3h 4h 5h –35 –50 –75 –125 –220 –410 6h–775 7h–1500 8.3.6.2Zero-crossDetectComparator Thezero-crossparestheamplifiedechosignalatCOMPINwithitsreferencevoltage,whichisVCOM.AsshowninFigure21,paratorproducesalow-to-hightransitionwhentheamplitudeoftheechosignalrisesaboveVCOM.paratorproducesahigh-to-lowtransitionwhentheechoamplitudefallsbelowVCOM–VHYST.Thebuilt-innegative-sidedhysteresisof10mVinreferencetoVCOMensuresuratezero-crosstimeinstancesassociatedwiththerisingedgesoftheechosignalandimmunityofparatoroutputtonoise. Copyright©2015,TexasInstrumentsIncorporated 15 TDC1011-Q1 ZHCSDU8–JULY2015 SignalintoCOMPIN VCOM VHYST=10mV ZeroCrossDetectOutput Figure21.Zero-CrossDetectorOutputSignal Theoutputofthezero-crossparatorispassedtotheeventmanager,wheredependingonthedecisionoftheparator. 8.3.6.3EventManager TheeventmanagerisadigitalstatemachineintheSTOPpulsegenerationcircuitoftheTDC1011.TheeventmanagercontrolsthemaximumnumberofSTOPpulsestogenerateontheSTOPpinandthereceivemodefortheSTOPpulsegeneration.ThenumberofSTOPpulsesisconfiguredintheNUM_RXfieldintheCONFIG_1register.ThereceivemodeisselectedintheRECEIVE_MODEbitoftheCONFIG_4register.SeesectionsSingleEchoReceiveModeandMultipleEchoReceiveModefordetailsaboutthereceivermodesoftheTDC1011. AnexampleforNUM_RX=2handRECEIVE_MODE=0isshowninFigure22.WhentheechosignalamplitudeexceedsvaluessmallerthanVTHLD,thethresholdparatorindicatestotheeventmanagertoqualifythenextzero-crosseventasvalid.Whenthequalifiedzero-crossisdetectedbythezero-crossparator,theeventmanagerpassesthepulsetotheSTOPpinuntilthenumberofreceiveeventsprogrammedinNUM_RXisreached. STOP COMPIN VCOMVTHLD GND PassesVTHLD PassesVTHLD Qualifiedforzero-cross Qualifiedforzero-cross Figure22.SignalQualification,Zero-crossDetectionandSTOPPulseGeneration 16 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 8.3.7Common-modeBuffer(VCOM) Theoutputofthemon-modebufferispresentattheVCOMpin.Thispinshouldbebypassedtogroundwithalow-leakage10-nFcapacitoranditshouldnotbeloadedwithmorethan20µA.monmodebuffercanbedisabledwiththeVCOM_SELbitintheCONFIG_2register.Ifdisabled,anexternalreferencevoltagemustbeappliedtotheVCOMpin. Duringatime-of-flightmeasurement,mon-modereferencewilltakeapproximately16µstosettleifstartingfromzeroinitialconditions.Usingalargercapacitorwillincreasethesettlingtimeofthemonmodereference.TheimplicationsofalargerVCOMcapacitorarefurtherexploredintheCommon-modeReferenceSettlingTimesection. 8.3.8TemperatureSensor TDC1011 MEAS_MODE tof_start MUX START MEAS_MODE tof_ MUX STOP TempSensor RREF RTD1 RTD1(external) RTD2 RTD2(external) Figure23.TemperatureSensorMeasurement uratemeasurementsoflevel,andconcentrationmaypensationforthetemperaturedependencyofthespeedofsoundinthemedium.TheTDC1011providestwotemperaturesensorconnections,allowingtomeasureuptotwolocationswithRTDs,asshowninFigure23. ThetemperaturesensorblocksupportsPT1000orPT500sensors.ThetypeofRTDusedmustbeselectedintheTEMP_RTD_SELbitoftheCONFIG_3register.Thesystemrequiresatemperature-stableexternalreferenceresistor(RREF).IftheRTDtypeisPT500,thenRREFshouldbe500Ω.IftheRTDtypeisPT1000,thenRREFshouldbe1kΩ.Thereferenceresistorneedstohaveeitheralowtemperaturecoefficientorbecalibratedfortemperatureshift. ThelogictiminginatemperaturemeasurementiscontrolledbytheTEMP_CLK_DIVbitintheCONFIG_3register.AsshowninFigure24,theexternalclockcanbedividedby8orbythevalueresultingfromtheTX_FREQ_DIVfieldconfigurationintheCONFIG_0register.Itismendedtooperatethetemperaturemeasurementblockatfrequenciesof1MHzorless. Copyright©2015,TexasInstrumentsIncorporated 17 TDC1011-Q1 ZHCSDU8–JULY2015 CLKIN¦CLKIN 0x03[4]±TEMP_CLK_DIV O8O2TX_FREQ_DIV+
1 0 ¦TEMP
1 TTEMP=
1 ¦TEMP 0x00[7:5]±TX_FREQ_DIVFigure24.TimingSourcefortheTemperatureMeasurement 8.3.8.1TemperatureMeasurementwithMultipleRTDs ThetemperaturemeasurementmodeisselectedbysettingtheMEAS_MODEbitintheCONFIG_2registerto1.Atemperaturemeasurementisstartedbysendingatriggerpulse.Afterthetemperaturemeasurementplete,theTDC1011returnstoSLEEPmode.ToreturntoTOFmeasurementmode,resettheMEAS_MODEbitto0. ThetemperaturesensormeasurementcanbeperformedwithouttheneedofanexternalADC.Thetemperaturesensorblockoperatesbyconvertingtheresistanceofareference,RREF,anduptotwoRTDsintoaseriesofSTARTandSTOPpulses.Theintervalbetweenthepulsesisproportionaltothemeasuredresistance,andtherefore,thetemperature.AsshowninFigure25,theTDC1011performsthreemeasurementspertriggereventandgeneratesthecorrespondingpulsesontheSTARTandSTOPpins. TRIGGER Reference RTD1 RTD2 STARTSTOP td1tREF td2tRTD1 Figure25.TemperatureMeasurementOutputTiming tRTD2 TheresistanceofRTD1andRTD2canbecalculatedfromthetimeintervalsinFigure25asfollows: RRTDxRREFKtREF tRTDx
(3) Witha1-kΩreferenceresistor,thetREFintervalisapproximately200μs.Thefollowingintervals,tRTD1andtRTD2,willdependontheresistanceoftheRTDs.Thetimedelaybetweenmeasurements,td1andtd2,canbeapproximatedasfollows: td1=(51×TTEMP)+(tRTD1×0.55)
(4) td2=(51×TTEMP)+(tRTD2×0.55)
(5) Forexample,twoPT1000sensorsat0°Cwillhaveanapproximateresistanceof1kΩ;thesameasthereferenceresistorinthisexample.Givenanexternal8-MHzclockandthedefaulttemperatureclockdivide-by-8fromtheTEMP_CLK_DIVbit,theoverallmeasurementtimebetweentheSTARTpulseandthelastSTOPpulseisapproximately922µs. 18 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 8.3.8.2TemperatureMeasurementwithaSingleRTD ThetemperaturesensingblockcanbeconfiguredtomeasureasingleRTDbysettingtheTEMP_MODEbitinregisterCONFIG_3to1.WhenthetemperaturemeasurementrunsinPT1000mode(TEMP_RTD_SEL=0),thefirstintervalcorrespondstoRREF,thesecondintervalisaredundantmeasurementonRREFandshouldbeneglected,andthethirdintervalcorrespondstoRTD1.ThisoperationisrepresentedinFigure26. TRIGGER Reference Discard RTD1 STARTSTOP tREF td1 td2 ½tREF tRTD1 Figure26.TemperatureMeasurementwithaSinglePT1000 TheresistanceofRTD1canbecalculatedusingEquation3.ThetimedelaybetweenmeasurementscanbeapproximatedusingEquation4andEquation5,withtheexceptionthatinthiscase,td1isafunctionof½tREFandtd2isafunctionoftRTD1. IfthetemperaturemeasurementrunsinPT500mode(TEMP_RTD_SEL=1),thefirstintervalisaredundantmeasurementonRREFandshouldbeneglected,thesecondintervalcorrespondstoRREF,andthethirdintervalcorrespondstoRTD1.ThisoperationisrepresentedinFigure27. TRIGGER Discard Reference RTD1 STARTSTOP td1 td2 2KtREF tREF tRTD1 Figure27.TemperatureMeasurementwithaSinglePT500 TheresistanceofRTD1canbecalculatedusingEquation3.ThetimedelaybetweenmeasurementscanbeapproximatedusingEquation4andEquation5,withtheexceptionthatinthiscase,td1isafunctionoftREFandtd2isafunctionoftRTD1. 8.4DeviceFunctionDescription 8.4.1Time-of-FlightMeasurementMode TheTOFmeasurementmodeisselectedbysettingtheMEAS_MODEbitintheCONFIG_2registerto0. 8.4.1.1LiquidLevelorFluidIdentification TheTDC1011performsasingleTOFmeasurementafterreceivingatriggersignalandreturnstotheSLEEPmodewhenthemeasurementplete. 8.4.2StateMachine AstatemachineintheTDC1011managestheoperationofthevariousmeasurementmodes(seeFigure28).Atpower-on,thestatemachineisresetandmostblocksaredisabled.Afterthepower-onsequenceplete,thedevicegoesintoSLEEPmodeiftheENpinisloworintoREADYmodeiftheENpinishigh.IntheSLEEPorREADYstate,theTDC1011isabletoreceivemandstosetregistersandconfigurethedeviceforameasurementmode. Copyright©2015,TexasInstrumentsIncorporated 19 TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) NOTEAlthoughtheSPIblockisalwaysactive,itisnotmendedtoperformconfigurationchangeswhilethedeviceisactive.ConfigurationchangesshouldbeperformedwhilethedeviceisintheSLEEPstateorintheREADYstate. IftheENpinishighandatriggersignalisreceived,thestatemachinewillbegintheexecutionoftheconfiguredmeasurement.ThestatemachinewillreturntotheSLEEPstateafterthemeasurementpleted. ThedevicecanbeforcedtoexitameasurementbyapplyingalogichighontheRESETpinhighoralogiclowontheENpin. SWReset Timeout=1EN=Low HWReset SLEEPstateEN=High ERROR_FLAGSregister(0x07):NWriting1tobit[1]oftheERROR_FLAGS registercancelsanyactivemeasurementandreturnstosleepmodeorreadymodetNotandsetsCountto0andCH-flagtoFALSE. Ready Triggerpulse?
YesTXBurstOutputSTART Pulse RXActive OutputSTOPpulses Mode?
Figure28.SimplifiedTDC1011StateMachineDiagram 20 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued)8.4.3TRANSMITOperation 8.4.3.1TransmissionPulseCount ThenumberofTXpulsesgeneratedbytheTDC1011todriveanultrasonictransducerisprogrammableusingtheNUM_TXfieldlocatedintheCONFIG_0register. 8.4.3.2TX180°PulseShift AsshowninFigure29,thetransmitterblockcanadda180°shiftatapositionintheTXsignal.ThepositionofthepulseshiftissetbytheTX_PH_SHIFT_POSfieldintheCONFIG_4registerandallowsgeneratingaspecificsignalpattern. Generationof180°burstforTxSignature Figure29.TransmitterPulseSignature,180°Burst AsshowninFigure30,enablingtheTX180°pulseshifthastheeffectofdecreasingthenumberoftransmittedpulsesby1. NormalOperation:NUM_TX=0x07TX_PH_SHIFT_POS=0x1F 180|Shift:NUM_TX=0x07TX_PH_SHIFT_POS=0x03 Pos.0Pos.1Pos.2Pos.3Pos.4 Figure30.TransmitterPulseSignature Pos.5 Pos.6 Insomecases,the180°pulseshiftmayhelpimprovingtheturn-offtimeofatransducer,andthussuppressthetransmitringing. The180°pulseshiftisdisabledbysettingTX_PH_SHIFT_POStoposition31.Settingthe180°pulseshifttopositions0or1isnotmended. 8.4.3.3TransmitterDamping Thetransmitterdampingfeatureallowsforimprovedcontroloverthetransducersignalgeneration.DampingextendsthedurationofthelastTXpulsetohelpdissipateringingandimprovethetransducer'sturn-offtime(seeFigure31andFigure32).Theuracyofmeasurementscanbeimprovedbyhavingafastertransducerturn-offtime.DampingiscontrolledwiththeDAMPINGbitintheCONFIG_2register. Copyright©2015,TexasInstrumentsIncorporated 21 TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) Dampingextendsthedurationofthelastpulsetodissipateringing Figure31.TransmitterDamping(5TxPulsesWithaDampingPulse) Amplitude 8.0Dampingdisabled 6.0Dampingenabled 4.0 2.0 0.0 -2.0 -4.0 -6.0 -8.0 0.0 2.0 4.0 6.0 8.0 10.012.014.016.018.020.0 7LPH
V Figure32.TransmitterDampedEcho Therearetwoinvalidbinationsofthedampingfeaturethatmayresultinunexpectedbehavior.First,dampingshouldnotbinedwiththe180°pulseshiftdescribedintheprevioussection.Second,dampingshouldnotbeenabledifthenumberofTXpulsesissetto31. 8.4.4RECEIVEOperation 8.4.4.1SingleEchoReceiveMode SingleEchomodecanbeusedforfluididentificationmeasurementsorlevelapplicationswheretransducercarrierfrequencyinformationisrequired.ThedevicecanbeconfiguredforSingleEchomodebysettingtheRECEIVE_MODEbitto0intheCONFIG_4register.InSingleEchomode,thedevicewillgenerateSTOPpulsesforeveryzero-crossqualifiedbytheparator,uptothenumberofexpectedSTOPeventsconfiguredintheNUM_RXfieldintheCONFIG_1register. Theparatorqualifiesthenextzero-crossafteranRXamplitudesmallerthantheprogrammedthresholdvoltageisdetected.Thezero-crossdetectorwillprovideoutputpulsescorrespondingtotherisingedgeofthereceivedsignalcrossingtheVCOMlevel,asshowninFigure33.ThethresholdvoltagecanbesetintheECHO_QUAL_THDLfieldintheCONFIG_3register. 22 Copyright©2015,TexasInstrumentsIncorporated DeviceFunctionDescription(continued) Zero-crossingdetectedafterthresholdexceeded COMPIN TDC1011-Q1 ZHCSDU8–JULY2015 VCOM ECHO_QUAL_THLD Threshold Signalexceedsthreshold OutputonSTOPpin Maximumnumberofrequestedevents(5inthisfigure)returned;subsequenteventsnotreported Figure33.SingleEchoReceiveMode(5STOPEvents) IfthenumberofexpectedpulsesprogrammedinNUM_RXisnotreceivedorthetime-of-flightoperationtimesout,theTDC1011willindicateanerrorconditionintheERROR_FLAGSregisterandwillsettheERRBpinlow. 8.4.4.2MultipleEchoReceiveMode TheMultipleEchomodeisintendedforuseinlevelsensingapplicationsanddistance/displacementmeasurementsinwhichmultipleechoes(burst)arereceived.Inthiscondition,eachreceivedechogroupwillbetreatedasasinglepulseontheSTOPpin.Upto7STOPpulsescanbegeneratedbasedonthevalueoftheNUM_RXfieldintheCONFIG_1register.MultiechomodecanbeenabledbysettingtheRECEIVE_MODEbitto1intheCONFIG_4register.ArepresentationofmultipleechoSTOPpulsegenerationisshowninFigure34. COMPIN VCOMProgrammed threshold OutputonSTOPpin NopulseonSTOPpinbecausesignaldidnotexceedthreshold NopulseonSTOPpinbecausemaximumnumberofprogrammedevents(5inthisexample)alreadyproduced. Figure34.MultipleEchoReceiveMode(5STOPEvents) Copyright©2015,TexasInstrumentsIncorporated 23 TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) TherisingedgeofaSTOPpulseisgeneratedbyazero-crossingevent.AsintheSingleEchoReceiveMode,theparatorqualifiesthenextzero-crossafteranRXamplitudesmallerthantheprogrammedthresholdvoltageisdetected.TheSTOPpulsewillextenduntilazero-crossaftertheRXamplitudeisnolongersmallerthanthethresholdvoltage(seeFigure35). Zero-crossingdetectedafterthresholdexceeded Signalzero-crossingwithoutexceedingthreshold COMPIN VCOM Programmedthreshold OutputonSTOPpin Signalexceedsthreshold Figure35.MultipleEchoReceiveMode(Zoom-in) IfthenumberofexpectedpulsesprogrammedinNUM_RXisnotreceivedorthetime-of-flightoperationtimesout,theTDC1011willindicateanerrorconditionintheERROR_FLAGSregisterandwillsettheERRBpinlow. 8.4.5Timing 8.4.5.1TimingControlandFrequencyScaling(CLKIN)0x09[2]±CLOCKIN_DIV CLKIN¦CLKIN O2CLOCKIN_DIV 1¦0T0= ¦
0 O2TX_FREQ_DIV+
1 ¦
1 1T1= ¦
1 0x00[7:5]±TX_FREQ_DIVFigure36.ExternalClockDivisionTree AlltransmitandreceivefunctionsequencingissynchronoustotheexternalclockappliedtotheCLKINpin.TheexternalclockisdividedtogeneratetwointernalclockswithcorrespondingtimeperiodsdenotedasT0andT1inFigure36.ThedivisionfactorusedtogenerateT0iscontrolledwiththeCLOCKIN_DIVbitintheCLOCK_RATEregister.ThedivisionfactorusedtogenerateT1iscontrolledwiththeTX_FREQ_DIVfieldlocatedintheCONFIG_0register. TheSPIblockissynchronouswiththeclockappliedtotheSCLKpin,anditisindependentoftheclockappliedtoCLKIN.SeetheSerialPeripheralInterface(SPI)sectionforpletedescriptionoftheSPIblock. 24 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) 8.4.5.2TX/RXMeasurementSequencingandTiming TheTDC1011automaticallysequencestheTXandRXfunctionality.AfterreceivingapulseedgeontheTRIGGERpin,theTDC1011resynchronizestotheCLKINsignal,andsendsaTXburst. Thetriggeredgepolarityisconfiguredtorisingedgebydefault,butitcanbechangedtofallingedgebysettingtheTRIG_EDGE_POLARITYbitintheCONFIG_4registerto1. Afteradevicereset,thesystemmustwaitadeterminedtimebeforesendingthenexttriggersignal.Thetypicalresettotriggerwaittimeis3×T1+50ns. 8.4.6Time-of-Flight(TOF)Control ThepossibleconfigurationsoftheTX/RXsequencingduringatime-of-flightmeasurementcanbedividedintothreecases:ShortTOFMeasurement,StandardTOFMeasurementandStandardTOFMeasurementwithPowerBlanking.Overall,thecasesdifferintheorderofsequencing,powersavingandecholisteningwindows.Thebehaviorofeachcaseisdescribedinthesectionstofollow. 8.4.6.1ShortTOFMeasurement TRIG (seeNoteA) AnalogOFFAnalogONEcholistenperiod TX STARTRX (seeNoteC) (seeNoteB) STOP READY COMMON-MODE128xT0 AUTOZERO2AUTOZERO_PERIODx64xT0 TRANSMITNUM_TXxT1 MASK2SHORT_TOF_BLANK_PERIODx8xT0 ECHOLISTEN2TOF_TIMEOUT_CTRLx128xT0 ENDREADY1xT1
A.Common-modesettlingtime.B.IfNUM_TX<3,thewidthoftheSTARTpulseisequaltoNUM_TX×T1.IfNUM_TX≥3,thewidthoftheSTART pulseisequalto3×T1. Figure37.ShortTOFMeasurement Inashorttimeofflightmeasurement,theRXpathisactivatedbeforetheTXburst,asshowninFigure37. TheshortTOFisthedefaultmeasurementsequenceselectedatpower-on.TheshortTOFmeasurementisselectedifthevalueoftheTIMING_REG[9:0]fieldislessthan30,oriftheFORCE_SHORT_TOFbitissetto1.TheTIMING_REG[9:0]isa10-bitwidefield,withits2mostsignificantbitslocatedintheTOF_1register,andthe8leastsignificantbitslocatedintheTOF_0register.TheFORCE_SHORT_TOFbitislocatedintheTIMEOUTregister. parator'sinputoffsetisstoredinaninternalcapacitorduringtheauto-zeroperiod.Thelengthoftheauto-zeroperiodiscontrolledbytheAUTOZERO_PERIODfieldintheCLOCK_RATEregister. Copyright©2015,TexasInstrumentsIncorporated 25 TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) ThelengthofthewindowwhenparatorsareabletoqualifyandgenerateSTOPpulsesisconfiguredbytheTOF_TIMEOUT_CTRLfield.Atimeoutwillurifthenumberofexpectedpulsesisnotreceivedduringtheallocatedtimeandanerrorconditionisrep
与MSP430/C2000MCU、电源、无线网络和源代码配套使用时，TI可提供完整的超声波感测解决方案。
TI的超声波AFE可编程且具有灵活性，可适应广泛的应用和终端设备。
TDC10111可针对多种发射脉冲和频率、增益和信号阈值进行配置，以便在多种传感器频率（31.25kHz至4MHz）和Q系数下使用。
同样，接收路径可编程设定，因此在更远的距离/更大的箱体尺寸范围内也能够检测到通过多种介质传播的超声波。
TDC1011可选择不同的工作模式，并且针对低功耗进行了优化，这使得它成为电池供电应用的理想选择。
低噪声放大器和比较器产生的抖动极低，可实现皮秒级分辨率和精度。
器件型号TDC1011-Q1 器件信息
(1) 封装TSSOP(PW-28) 封装尺寸（标称值）9.70mmx4.40mm
(1)要了解所有可用封装，请见数据表末尾的可订购产品附录。
1 AnIMPORTANTNOTICEattheendofthisdatasheetaddressesavailability,warranty,changes,useinsafety-criticalapplications, intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA. EnglishDataSheet:SNAS670 TDC1011-Q1 ZHCSDU8–JULY2015 目录 1特性..........................................................................12应用..........................................................................13说明..........................................................................14修订历史记录...........................................................25PinConfigurationandFunctions.........................36Specifications.........................................................4 6.1AbsoluteMaximumRatings......................................46.2ESDRatings............................................................46.3mendedOperatingConditions.......................46.4ThermalInformation..................................................46.5ElectricalCharacteristics...........................................56.6TimingRequirements................................................76.7SwitchingCharacteristics..........................................76.8TypicalCharacteristics..............................................87ParameterMeasurementInformation................108DetailedDescription............................................118.1Overview.................................................................118.2FunctionalBlockDiagram.......................................11 8.3FeatureDescription.................................................128.4DeviceFunctionDescription...................................198.5Programming..........................................................288.6RegisterMaps.........................................................309ApplicationandImplementation........................369.1ApplicationInformation............................................369.2TypicalApplications................................................3610PowerSupplymendations.....................4111Layout...................................................................4211.1LayoutGuidelines.................................................4211.2LayoutExample....................................................4212器件和文档支持.....................................................4312.1器件支持................................................................4312.2社区资源................................................................4312.3商标.......................................................................4312.4静电放电警告.........................................................4312.5Glossary................................................................4313机械、封装和可订购信息.......................................43 4修订历史记录 日期2015年7月 修订版本* 注释首次发布。
2 Copyright©2015,TexasInstrumentsIncorporated 5PinConfigurationandFunctions TSSOP(PW)28Pin TopView NC1RX2VCOM3LNAOUT4PGAIN5PGAOUT6COMPIN7RTD18RTD29RREF10RES11ERRB12START13STOP14 TDC1011 28TX27NC26GND25CLKIN24VDD23VDD22VIO21SDO20SDI19CSB18SCLK17RESET16TRIGGER15EN TDC1011-Q1 ZHCSDU8–JULY2015 PINNAMENCRXVCOMLNAOUTPGAINPGAOUTCOMPINRTD1RTD2RREFRESERRBSTARTSTOPENTRIGGERRESETSCLKCSBSDISDOVIOVDD CLKINGNDNCTX PinFunctions NO.12345678910111213141516171819202122 23,24 25262728 TYPE
(1) IPOIOIOOOIOOOIIIIIIOPP IG
O DESCRIPTION NoConnect(leavefloating)ReceiveinputmonmodevoltagebiasLownoiseamplifieroutput(foracdecouplingcapacitor)ProgrammablegainamplifierinputProgrammablegainamplifieroutputEchoqualificationandzero-crossingdetectorinputResistancetemperaturedetectorchannel1Resistancetemperaturedetectorchannel2ReferenceresistorfortemperaturemeasurementReserved(connecttoGND)Errorflag(opendrain)StartpulseoutputpulseoutputEnable(activehigh;whenlowtheTDC1011isinSLEEPmode)TriggerinputReset(activehigh)SerialclockfortheSPIinterfaceChipselectfortheSPIinterface(activelow)SerialdatainputfortheSPIinterfaceSerialdataoutputfortheSPIinterfacePositiveI/OsupplyPositivesupply;allVDDsupplypinsmustbeconnectedtothesupply.Placea100-nFbypasscapacitortogroundincloseproximitytothepin.ClockinputNegativesupplyNoConnect(leavefloating)Transmitoutput
(1)G=Ground,I=Input,O=Output,P=Power Copyright©2015,TexasInstrumentsIncorporated
3 TDC1011-Q1 ZHCSDU8–JULY2015 6Specifications 6.1AbsoluteMaximumRatings Overoperatingfree-airtemperaturerange(unlessotherwisenoted)
(1)(2) VDD Analogsupplyvoltage,VDDpins VIO I/Osupplyvoltage(VIOmustalwaysbelowerthanorequaltoVDDsupply) VI Voltageonanyanaloginputpin
(3) VI Voltageonanydigitalinputpin
(3) II Inputcurrentatanypin TJ Operatingjunctiontemperature Tstg Storagetemperaturerange MIN MAX UNIT –0.3 6.0
V –0.3 6.0
V –0.3 VDD+0.3
V –0.3 VIO+0.3
V 5 mA –40 125 °
C –65 150 °
C
(1)StressesbeyondthoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratingsonly,whichdonotimplyfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedundermendedOperatingConditions.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability.
(2)Allvoltagesarewithrespecttoground,unlessotherwisespecified.
(3)Whentheinputvoltageatapinexceedsthepowersupplies,thecurrentatthatpinmustnotexceed5mAandthevoltage(VI)atthat pinmustnotexceed6.0V. 6.2ESDRatings V(ESD)Electrostaticdischarge Human-bodymodel(HBM),perAECA100-002
(1) Charged-devicemodel(CDM),perAECQ100-011 Allpins Cornerpins(1,14,15and28) VALUE±2000±500 ±750
(1)AECQ100-002indicatesHBMstressingisdoneinordancewiththeANSI/ESDA/JEDECJS-001specification. UNITV 6.3mendedOperatingConditions Overoperatingfree-airtemperaturerange(unlessotherwisenoted) VDDVIOVIVIƒCLKINTJ Analogsupplyvoltage,VDDpinsDigitalsupplyvoltage,(VIOmustalwaysbelowerthanorequaltoVDDsupply)VoltageonanyanaloginputpinVoltageonanydigitalinputpinOperatingfrequencyOperatingjunctiontemperature MIN2.71.8GNDGND0.06–40 MAX5.5VDDVDDVIO16125 UNITVVVV MHz°
C 6.4ThermalInformation
(1) THERMALMETRIC RθJARθ)RθJBψJTψJB Junction-to-ambientthermalresistanceJunction-to-case)thermalresistanceJunction-to-boardthermalresistancecharacterizationparameterJunction-to-boardcharacterizationparameter TDC1011TSSOPPW(28PINS) 83.5 29.9 40.8 2.4 40.3 UNIT°C/W
(1)Formoreinformationabouttraditionalandnewthermalmetrics,seetheICPackageThermalMetricsapplicationreport,SPRA953.
4 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 6.5ElectricalCharacteristics Theelectricalratingsspecifiedinthissectionapplytoallspecificationsinthisdocument,unlessotherwisenoted.Thesespecificationsareinterpretedasconditionsthatdonotdegradethedeviceparametricorfunctionalspecificationsforthelifeoftheproductcontainingit.TA=25°
C,VDD=VIO=3.7V,VCOM=VCM=VDD/2,CVCOM=10nF(unlessotherwisenoted). PARAMETER TESTCONDITIONS MIN TYP MAXUNIT TRANSMITTERSIGNALPATH(TX) VOUT(TX) Outputvoltageswing ƒout=1MHz,RL=75ΩtoVCM HIGHLOW VDD–0.32
V 0.32
V IOUT(TX) Outputdrivecurrent ƒout=1MHz,RL=75ΩtoVCM 22 mARMS ƒOUT(TX) OutputTXfrequency ƒCLKIN=8MHz,divide-by-2(programmable;seeTransmitterSignalPath)
4 MHz RECEIVERSIGNALPATH(RX) ΔtSTOP STOPcycle-to-cyclejitter LNAcapacitivefeedback,GPGA=6dB,ƒIN=1MHz,VIN=100mVPP,CVCOM=1µFandFigure14 50 psRMS LNA GLNA LNAgain Capacitivefeedback,CIN=300pF,ƒIN=1MHz,RL=100kΩtoVCM,CVCOM=1µ
F 20 dB enLNA LNAinputreferrednoisedensity Capacitivefeedback,CIN=300pF,ƒ=1MHz,VDD=3.1V,VIN=VCM,RL=∞,CVCOM=1µ
F 2 nV/√Hz VIN(LNA) Inputvoltagerange Resistivefeedback,RL=1kΩtoVCM,CVCOM=1µ
F HIGHLOW VCM+(VCM–0.24)/(GLNA)
V VCM–(VCM–0.24)/(GLNA)
V VOUT(LNA) Outputvoltagerange Resistivefeedback,RL=1kΩtoVCM,CVCOM=1µ
F HIGHLOW VDD–0.24
V GND+0.24
V SRLNA Slewrate
(1) Resistivefeedback,RL=1kΩtoVCM,100mVstep,CVCOM=1µ
F 9 V/μs BWLNA –3-dBbandwidth Capacitivefeedback,CIN=300pF,RL=100kΩtoVCM,CVCOM=1µ
F 5 MHz VOS(LNA) LNAinputoffsetvoltage Resistivemode,VIN=VCM,RL=∞ ±320 µ
V VCOM VCOM VCOMoutputvoltageVCOMoutputerror CVCOM=1µ
F VCM
V 0.5% PGA VIN(PGA) PGAinputrange RL=100kΩtoVCM,CL=10pFtoGND HIGHLOW VCM+(VCM–0.06)/(GPGA)
V VCM–(VCM–0.06)/(GPGA)
V GPGAMIN PGAmingain
0 dB GPGAMAX PGAmaxgain DC,RL=∞,CL=10pF 21 dB ΔGPGA PGAgainstepsize
3 dB GE(PGA) PGAgainerror DC,GPGA=0dB,RL=∞,CL=10pF 5% TCGPGA PcoGeAfficgiaeinnttemperatureDC,GPGA=0dB,RL=∞,CL=10pF 170 ppm/°
C enPGA PGAinputreferrednoisedensity GPGA=21dB,ƒ=1MHz,VDD=3.1V,VIN=VCM,RL=∞,CVCOM=1µ
F 3.1 nV/√Hz VOUT(PGA) Outputrange RL=100kΩtoVCM,CL=10pFtoGND HIGHLOW VDD–0.06
V 60 mV BWPGA –3-dbbandwidth GPGA=21dB,RL=100kΩtoVCM,CL=10pF,CVCOM=1µ
F 5 MHz SRPGA Slewrate
(1) GPGA=21dB,RL=100kΩtoVCM,CL=10pF,CVCOM=1µ
F 12.5 V/µs
(1)Theslewrateismeasuredfrom10%to90%andisrepresentedbytheaverageoftherisingandfallingslewrates. Copyright©2015,TexasInstrumentsIncorporated
5 TDC1011-Q1 ZHCSDU8–JULY2015 ElectricalCharacteristics(continued) Theelectricalratingsspecifiedinthissectionapplytoallspecificationsinthisdocument,unlessotherwisenoted.Thesespecificationsareinterpretedasconditionsthatdonotdegradethedeviceparametricorfunctionalspecificationsforthelifeoftheproductcontainingit.TA=25°
C,VDD=VIO=3.7V,VCOM=VCM=VDD/2,CVCOM=10nF(unlessotherwisenoted). PARAMETER TESTCONDITIONS MIN TYP MAXUNIT ZEROCROSSCOMPARATOR VOS(COMP) Inputoffsetvoltage
(2) ReferredtoVCOM ±115 µ
V enCOMPHYSTCOMP Zeroparatorinputreferrednoise
(2) Hysteresis
(2) 1MHzReferredtoVCOM
5 nV/√Hz -10 mV THRESHOLDDETECTOR VTHDET Thresholdlevel ECHO_QUAL_THLD=0h,VCOMreferredECHO_QUAL_THLD=7h,VCOMreferred TEMPERATURESENSORINTERFACE
(3) TERROR Temperature RREF=1kΩ,PT1000range:–40to125°C
(4) measurementuracyRREF=1kΩ,PT1000range:–15°Cto85°C
(4) –35 mV –1.5
V 1 °
C 0.5 °
C Relativeuracy RREF=1kΩ,RRTD1=RRTD2=1.1kΩ 0.02 °CRMS TGE Gainerror 5.8 m°C/°
C POWERSUPPLY Sleep(EN=CLKIN=TRIGGER=low) 0.61 µ
A Continuousreceivemode,LNAandPGA bypassed IDD VDDsupplycurrent Continuousreceivemode,LNAandPGAactive Temp.measurementonly(PT1000mode)
(5) Temp.measurement(PT500mode)
(6) 2.8 3mA 6.2 7.5mA 370 400µ
A 500 540µ
A IIOVcuIOrresnutp(2p)lysleepSleep(EN=CLKIN=TRIGGER=low)
2 nA DIGITALINPUT/OUTPUTCHARACTERISTICS VILItnhpreusthloogldiclow 0.2×VIO
V VIHItnhpreusthloogldichigh 0.8×VIO
V SDOpin,100-μAcurrent 0.2
V SDOpin,1.85-mAcurrent 0.4
V Outputlogiclow STARTandSTOPpins,100-μAcurrent VOL threshold STARTandSTOPpins,1.85-mAcurrent 0.5
V 0.6
V ERRBpin,100-μAcurrent 0.2
V ERRBpin,1.85-mAcurrent 0.4
V SDOpin,100-μAcurrent VIO–0.2
V SDOpin,1.85-mAcurrent VIO–0.6
V VOHOthuretpsuhtollodgichighSTARTandSTOPpins,100-μAcurrentVIO–0.5V STARTandSTOPpins,1.85-mAcurrent VIO–0.6
V ERRBpin,0-µAcurrent VIO–0.2
V IOMAX MaximumoutputcurrentforSDO,STARTandSTOP 1.85 mA
(2)Specifiedbydesign.
(3)Withidealponents.FormoredetailseeTempSensorMeasurementsection.
(4)PT1000RTDapproximateresistance:800Ω≡–52°C,931Ω≡–18°C,1.10kΩ≡26°C,1.33kΩ≡86°Cand1.48kΩ≡125°
C.
(5)Specifiedcurrentsinclude120μAwhichflowsthroughtheRTDsensorinPT1000mode(TEMP_RTD_SEL=0).
(6)Specifiedcurrentsinclude240μAwhichflowsthroughtheRTDsensorinPT500mode(TEMP_RTD_SEL=1).
6 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 6.6TimingRequirements TA=25°
C,VDD=VIO=3.7VandƒSCLK=1MHz(unlessotherwisenoted). MIN ƒSCLK Serialclockfrequency t1 Highperiod,SCLK 16 t2 Lowperiod,SCLK 16 t3 Set-uptime,nCStoSCLK 10 t4 Set-uptime,SDItoSCLK 12 t5 Holdtime,SCLKtoSDI 12 t6 SCLKtransitiontoSDOvalidtime 16 t7 Holdtime,SCLKtransitiontonCSrisingedge 10 t8 nCSinactive 17 t9 Holdtime,SCLKtransitiontonCSfallingedge 10 tr/tf Signalriseandfalltimes
(1) NOM1.8 MAX26
(1)Theslewrateismeasuredfrom10%to90%andisrepresentedbytheaverageoftherisingandfallingslewrates. UNITMHznsnsnsnsnsnsnsnsnsns SCLKCSB t9t3 t2 t1 t7 t4t5t8 D15 D14 D0 t6 90% PriorD1510% tr 90% PriorD110% PriorD0 tf Figure1.SPITimingDiagram 6.7SwitchingCharacteristics TA=25°
C,VDD=VIO=3.7V,ƒCLKIN=8MHz. PARAMETER TESTCONDITIONS START,STOP,ENABLE,RESET,CLOCKIN,TRIGGER,ERR TX_FREQ_DIV=2h,NUM_TX=
1 PWSTARTPulsewidthforSTARTsignalTX_FREQ_DIV=2h,NUM_TX=
2 TX_FREQ_DIV=2h,NUM_TX≥
3 tr/tf START Rise/falltimeforSTARTsignal 20%to80%,20-pFload tr/tfSTOPRise/falltimeforSTOPsignal20%to80%,20-pFload ƒCLKINtr/tfCLKIN MaximumCLKINinputfrequency CLKINinputrise/falltime
(1) 20%to80% tr/tfTRIGtEN_TRIG TRIGGERinputrise/falltime
(1)Enabletotriggerwaittime
(1) 20%to80% tRES_TRIGResettotriggerwaittime
(1) TX_FREQ_DIV=2h(seeTX/RXMeasurementSequencingandTiming)
(1)Specifiedbydesign. MIN TYP MAXUNIT
1 μs
2 μs
3 μs 0.25 ns 0.25 ns 16 MHz 10 ns 10 ns 50 ns 3.05 μs Copyright
©2015,TexasInstrumentsIncorporated
7 TDC1011-Q1 ZHCSDU8–JULY2015 6.8TypicalCharacteristics AtTA=25°C,unlessotherwisenoted. 500 OutputImpedanceMagnitude(||) 400 300 200 100
0 ±100 100 1k VDD=VIO=3.7V 10k 100k Frequency(Hz) CapacitiveFeedbackMode 500 OutputImpedanceMagnitude(|_ 400 300 200 100
0 1M 10M C001 RL=1kΩ ±100 100 1k VDD=VIO=3.7V 10k 100k Frequency(Hz) Gainof21dB 1M 10M C002 RL=1kΩ Figure2.LNAZOUTvsFrequency Input-referredNoise(nV/O,Ì 1098765432105k VDD=VIO=3.1V 50k 500k Frequency(Hz) CapacitiveFeedbackMode 2M C013 RL=∞ Figure3.PGAZOUTvsFrequency 10
9 Input-referredNoise(nV/O,Ì
8 7
6 5
4 3
2 1 05k VDD=VIO=3.7V 50kFrequency(Hz) Gainof21dB 500k 2M C014 RL=∞ Figure4.LNAInput-referredNoisevsFrequency Figure5.PGAInput-referredNoisevsFrequency OutputVoltage(250mV/DIV) OutputVoltage(250mV/DIV) VDD=VIO=3.7VVIN=100mV Time(1 s/DIV) ResistiveFeedbackMode C005 RL=1kΩfIN=100kHz VDD=VIO=3.7VVIN=100mV Time(1 s/DIV) Gainof21dB C006 RL=100kΩfIN=100kHz Figure6.LNAResponse8 Figure7.PGAResponseCopyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 TypicalCharacteristics(continued) AtTA=25°C,unlessotherwisenoted. 30 30 20 20 10 10 Gain(dB)Gain(dB)
0 0 ±10 ±10 ±20 ±20 Count(%)Count(%) ±3010k VDD=VIO=3.7VCIN=300pF 100k 1M Frequency(Hz) CapacitiveFeedbackMode 10M C007 RL=100kΩ Figure8.LNAGainvsFrequency 201816141210 86420 ±3010k VDD=VIO=3.7V 100k 1M Frequency(Hz) Gainof21dB 10M C008 RL=100kΩ Figure9.PGAGainvsFrequency 201816141210 86420 -300-200-100 0100200300-300-200-100 0100200300 Count(%)Count(%) VDD=VIO=5VVIN=100mV 201816141210 86420 Time(ps) LNACapacitiveFeedbackMode (SeeFigure14) C009 PGAGainof6dBfIN=1MHz Count>=10000 Figure10.RXJitterHistogram VDD=VIO=3.7VVIN=100mVTA=25C° Time(ps) LNACapacitiveFeedbackMode (SeeFigure14) C010 PGAGainof6dBfIN=1MHz Count>=10000 Figure11.RXJitterHistogram 201816141210 86420 -300-200-100 0100200300-300-200-100 0100200300 VDD=VIO=3.7VVIN=100mVTA=-40C° Time(ps) LNACapacitiveFeedbackMode (SeeFigure14) C011 PGAGainof6dBfIN=1MHz Count>=10000 Figure12.RXJitterHistrogam VDD=VIO=3.7VVIN=100mVTA=125C° Time(ps) LNACapacitiveFeedbackMode (SeeFigure14) C012 PGAGainof6dBfIN=1MHz Count>=10000 Figure13.RXJitterHistogram Copyright©2015,TexasInstrumentsIncorporated
9 TDC1011-Q1 ZHCSDU8–JULY2015 7ParameterMeasurementInformation INPUT CIN=300pF LNAIN LNAOUTCF1=1nF PGAIN PGAOUT RF1=1N CF2=51pF COMPIN CF3=51pF RF2=5.1N GND VCOM Figure14.ExternalCircuitsforJitterMeasurement 10 Copyright©2015,TexasInstrumentsIncorporated 8DetailedDescription TDC1011-Q1 ZHCSDU8–JULY2015 8.1Overview ThemainfunctionalblocksofTDC1011aretheTransmit(TX)andtheReceive(RX)Channels.Thetransmittersupportsflexiblesettingsfordrivingvariousultrasonictransducers,andthereceiverprovidesconfigurableblockswithawiderangeofsettingsforsignalconditioninginvariousapplications.ThereceivesignalchainconsistsofanLNA(LowNoiseAmplifier),aPGA(ProgrammableGainAmplifier),andtwoparatorsforechoqualificationandSTOPpulsegeneration. AmeasurementcycleisinitiatedwithatriggersignalontheTRIGGERpinofthedevice.Afteratriggersignalisasserted,anoutputpulseisgeneratedontheSTARTpin.ThissignalisusedasthetimereferencetobeginaTOFmeasurement.ThetransmittergeneratesprogrammableTXpulses,synchronoustotherisingedgeoftheSTARTpulse,todriveanultrasonictransducerandgenerateanultrasonicwavethatisshotthroughanacousticmedium.ThereceiverdetectstheultrasoundwavethattraveledthroughthemediumandgeneratesSTOPsignals.Whethertheultrasoundwaveisreceiveddirectlyorfromareflectionwilldependonthesystemconfiguration.TheSTOPsignalsareusedbyanexternalTime-to-DigitalConverter(TDC),whichfunctionsasaveryuratewatch.ThesystemmustincludeaTDCtomeasuretheTOFbasedontheintervalbetweentheSTARTandSTOPpulses.Insomeapplicationswithmedium-rangeuracyrequirements(nsrange),amicrocontrollercanbeusedtomeasuretheTOFduration.Inapplicationswithhigh-rangeuracyrequirements(psrange),TImendsusingtheTDC7200time-to-digitalconvertertomeasuretheTOFduration. Ineachapplication,theTDC1011hastobeconfiguredbyaserialinterface(SPI)forthevariousapplicationspecificparametersthatareexplainedinthefollowingsections. 8.2FunctionalBlockDiagram VDDVDDVIOCLKINENTRIGGERRESETRESERRBSDOSDISCLKCSB TXTx Generator ClockDivider RX ± + LNA PGA +20dB VCOM ±0to21dB VCOM TDC1011 SMControlUnit SerialInterface enable DACThresholdDetect EventManager MUX STARTSTOP MUX Zero-CrossDetectAnalogBiasTemp.Sense RTD1RTD2RREFVCOM COMPINPGAOUTPGAINLNAOUT GND Copyright©2015,TexasInstrumentsIncorporated 11 TDC1011-Q1 ZHCSDU8–JULY2015 8.3FeatureDescription 8.3.1TransmitterSignalPath TheTransmitter(TX)pathconsistsofaClockDividerblockandaTXGeneratorblock.TheclockdividerallowstheTDC1011todividetheclocksourcethatisconnectedtotheCLKINpindowntotheresonantfrequency(ƒR)ofthetransducerused.Theclockdividerallowsdivisionfactorsinpowersof2.ThedivisionfactoroftheclockdividercanbeprogrammedwiththeTX_FREQ_DIVfieldintheCONFIG_0register. TheTXGeneratorblockcandriveatransducerwithaprogrammablenumberofTXpulses.ThefrequencyofthesepulsesisdefinedasƒCLKIN/(2TX_FREQ_DIV+1),andshouldmatchtheƒRofthetransducer.ThenumberofpulsesisconfiguredbyprogrammingtheNUM_TXfieldintheCONFIG_0register. Forexample,forƒCLKIN=8MHzandTX_FREQ_DIV=2h(divideby8),thedividedclockfrequencyis1MHz. Inadditiontotheprogrammablenumberofpulses,theTXGeneratoralsoprovidesoptionstointroducea180⁰pulseshiftatpulsepositionnordampingthelastTXpulse.Insomesituations,dampingcanreducetheringingofthetransducerforveryshortTOFmeasurements.ThesefeaturesarefurtherdescribedintheTRANSMITOperationsectionofthedatasheet. 8.3.2ReceiverSignalPath TheRXsignalpathconsistsofanLNA,PGA,andapairparators.TheLNAandPGAprovidetherequiredamplificationofthereceivesignal.TheamplifiedreceivesignalisfedintoasetparatorswhichgeneratepulsesontheSTOPpinbasedontheprogrammedthresholdlevels.TheblockdiagramforthereceiverpathcanbeseeninFigure15. Ifthe20-dBto41-dBofgainprovidedbytheTDC1011isinsufficient,additionalgaincanbeaddedpriortotheCOMPINpin.Likewise,withastrongreceivedsignal,ifthegainfromtheLNAorPGAisnotneeded,theycanbebypassedandthetransducersignalcanbedirectlyconnectedtotheCOMPINpin. Aband-passfiltercenteredonthetransducer’sresponsecanbeusedbetweeneachstageofthereceiverpathtoreducethenoise;notethattheinputsoftheLNA,PGA,paratorsshouldbebiasedtotheVCOMpin’spotential.paratorsconnectedtotheCOMPINpinareusedforechoqualificationandgenerationofSTOPpulsesthatcorrespondtothezero-crossingsoftheechosignal.TheSTOPpulsesareusedwithaSTARTpulsetocalculatetheTOFoftheechointhemedium. enable VCOM ±LNA+ 20dB TDC1011 VCOM +PGA ±0to21dB MUX DACThresholdDetect EventManager STOP AnalogBiasTemp.SenseZero-CrossDetect RTD1RTD2RREFVCOM COMPINPGAOUTPGAINLNAOUTGND Figure15.TDC1011ReceiverPath 12 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 FeatureDescription(continued) 8.3.3LowNoiseAmplifier(LNA) TheLNAintheTDC1011’sfront-endlimitstheinput-referrednoiseandensurestiminguracyforthegeneratedSTOPpulses.TheLNAisaninvertingamplifierdesignedforaclosed-loopgainof20dBwiththeaidofanexternalinputcapacitororresistor,anditcanbeprogrammedfortwofeedbackconfigurations.Thebandpassconfiguration,referredtoascapacitivefeedbackmode,mustbinedwithaninputcapacitor.Thelowpassconfiguration,referredtoasresistivefeedbackmode,mustbinedwithaninputresistor.Themendedvaluesfortheponentsare300pFand900Ωrespectively. TheLNAcanbeconfiguredincapacitivefeedbackmodefortransducerswithresonantfrequenciesintheorder ofacoupleofMHz.ThisisdonebyclearingtheLNA_FBbitintheTOF_1registerto0.AsshowninFigure16, theexternalcapacitor,CIN,shouldbeplacedbetweenthetransducerandtheinputpin.Thisprovidesanin-bandgainofCIN/CF,whereCFistheon-chip30-pFfeedbackcapacitor.ProvidedthatCIN=300pF,thein-bandgainoftheLNAcircuitis: Gain CIN300pF10 inbandCF30pF
(1) CIN300pFRX CF30pF RF 9N VCOM ±LNA + LNAOUT Figure16.LNACapacitiveFeedbackConfiguration ThecapacitivefeedbackconfigurationoftheLNAhasaband-passfrequencyresponse.Thehigh-passcornerfrequencyissetbytheinternalponentsRF(9kΩ)andCF(30pF),andisapproximately590kHz.Thein-bandgainissetbythecapacitorratioandtheLNA’s50-MHzgain-bandwidthproductsetsthelow-passcornerofthefrequencyresponse.Forexample,anin-bandgainof10resultsinabandpassresponsebetween590kHzand5MHz. TheLNAcanbeconfiguredinresistivefeedbackmodefortransducerswithresonantfrequenciesintheorderofacoupleofhundredsofkHz.ThisisdonebysettingtheLNA_FBbitintheTOF_1registerto1.Inthisconfiguration,theinternalfeedbackcapacitorCFisdisconnected(seeFigure17),andtheDCgainoftheLNAcircuitisdeterminedbytheratiobetweentheinternalfeedbackresistorRF(9kΩ)andanexternalresistorRIN.ForRIN=900Ω,thegainofthecircuitis10. RF 9N RINTransducer900RX ±LNA+ LNAOUT VCOM Figure17.LNAResistiveFeedbackConfiguration TheLNAcanbebypassedanddisabledbywritinga1totheLNA_CTRLbitintheTOF_1register. Copyright©2015,TexasInstrumentsIncorporated 13 TDC1011-Q1 ZHCSDU8–JULY2015 FeatureDescription(continued) 8.3.4ProgrammableGainAmplifier(PGA) ThePGA,showninFigure18,isaninvertingamplifierwithaninputresistanceofRIN=500ΩandaprogrammablefeedbackresistorRFBthatcanbeprogrammedtoseta0-dBto21-dBgainin3-dBsteps.ThiscanbedonebyprogrammingthePGA_GAINfieldintheTOF_1register.ThebandwidthofthePGAisscaledbasedonitsprogrammedgain.ThetypicalbandwidthofthePGAwitha100-kΩloadtoVCManda10-pFcapacitortogroundarelistedinTable1. PGA_GAIN(Hex)0h1h2h3h4h5h6h7h Table1.TypicalPGABandwidth Gain(dB)036912151821 Bandwidth(MHz)19.016.814.412.310.08.26.65.0 ThePGAcanbebypassedanddisabledbywritinga1tothePGA_CTRLbitintheTOF_1register.TheoutputofthePGAshouldnotbeloadeddirectlywithcapacitancesgreaterthan10pF. RFB PGA_INRIN500: PGA_OUT PGA VCOM Figure18.TDC1011ProgrammableGainAmplifier 8.3.5ReceiverFilters ItismendedtoplacetwofiltersintheRXpathtominimizethereceivepathnoiseandobtainmaximumtiminguracy.AsshowninFigure19,onefilterisplacedbetweentheLNAOUTandthePGAINpins,andanotherfilterisplacedbetweenthePGAOUTandtheCOMPINpins. Withanin-bandgainof10,theLNAhasabandwidthof5MHz.Formostapplications,alow-passfilterbetweentheLNAOUTandPGAINpinsissufficient. AsshowninFigure19,thesecondfilterstagecanuseacascadeofalow-passfilter(RF1andCF3)followedbyahigh-passfilter(CF2andRF2)referencedtoVCOM.Designofthefilterisstraightforward.TheRF1andCF2canbechosenfirst.AreasonablesetofvaluesforRF1andCF2couldbe:RF1=1kΩ±10%andCF2=50pF±10%.GiventhecenterfrequencyofinteresttobeƒCandthefilterbandwidthtobeƒB,thevalueofCF3canbecalculatedas:
1 CF32SR ff F1CB
(2) RF2andCF2determinethehigh-passcornerofthefilter.RF2shouldbereferencedtoVCOMtomaintaintheDCbiaslevelatparatorinputduringtheechoreceivetime.ForvaluesofRF2largerthanRF1,therewillbelimitedloadingeffectfromthehigh-passfiltertothelow-passfilterresultinginmoreuratecornerfrequencies. Thechosenvaluesshowninthefigurebelowresultinahigh-passcornerfrequencyofabout600kHzandalow- passcornerfrequencyofabout3MHz. 14 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 plexfilterscanbeused;externalgainiseptableifthesignalamplitudeistoolow.Ifthepass-bandofthefilteriswiderthananoctave,itismendedtouseafilterdesignwhichhaslineargroupdelay. LNAOUTCF1=1nF PGAINPGAOUT RF1=1N CF2=50pF COMPIN CF3=53pF RF2=5N Figure19.Filterfora1-MHzOperationGND VCOM 8.3.6ComparatorsforSTOPPulseGeneration TheSTOPpulsegenerationblockoftheTDC1011containstwoparators(azero-crossdetectandaparator),athresholdsettingDAC,andaneventmanager. Comparatorauto-zeroperiodsuratthebeginningofeveryTOFreceivecycle.Duringtheseperiods,parator’sinputoffsetisstoredinaninternal2.5-pFcapacitor,anditissubtractedfromtheinputsignalduringtheechoprocessingphase.Thedurationofauto-zeroperiodisconfiguredwiththeAUTOZERO_PERIODfieldlocatedintheCLOCK_RATEregister. VCOMCOMPIN ZeroCrossDetect± + ECHO_QUAL_THLD +DAC ± VTHLD ThresholdDetect ± + RECEIVE_MODENUM_RX EventManager STOP Figure20.STOPPulseGenerationCircuit 8.3.6.1ThresholdDetectorandDAC ThethresholdparatorinFigureparestheechoamplitudewithaprogrammablethresholdlevel(VTHLD)controlledbyaDAC.TheDACvoltageissetbytheECHO_QUAL_THLDfieldinregisterCONFIG_3andprovides8programmablethresholdlevels,VTHLD.ThetypicallevelsaresummarizedinTable2: ECHO_QUAL_THLDTypicalVTHLD(mV) Table2.EchoQualificationThresholdLevels 0h 1h 2h 3h 4h 5h –35 –50 –75 –125 –220 –410 6h–775 7h–1500 8.3.6.2Zero-crossDetectComparator Thezero-crossparestheamplifiedechosignalatCOMPINwithitsreferencevoltage,whichisVCOM.AsshowninFigure21,paratorproducesalow-to-hightransitionwhentheamplitudeoftheechosignalrisesaboveVCOM.paratorproducesahigh-to-lowtransitionwhentheechoamplitudefallsbelowVCOM–VHYST.Thebuilt-innegative-sidedhysteresisof10mVinreferencetoVCOMensuresuratezero-crosstimeinstancesassociatedwiththerisingedgesoftheechosignalandimmunityofparatoroutputtonoise. Copyright©2015,TexasInstrumentsIncorporated 15 TDC1011-Q1 ZHCSDU8–JULY2015 SignalintoCOMPIN VCOM VHYST=10mV ZeroCrossDetectOutput Figure21.Zero-CrossDetectorOutputSignal Theoutputofthezero-crossparatorispassedtotheeventmanager,wheredependingonthedecisionoftheparator. 8.3.6.3EventManager TheeventmanagerisadigitalstatemachineintheSTOPpulsegenerationcircuitoftheTDC1011.TheeventmanagercontrolsthemaximumnumberofSTOPpulsestogenerateontheSTOPpinandthereceivemodefortheSTOPpulsegeneration.ThenumberofSTOPpulsesisconfiguredintheNUM_RXfieldintheCONFIG_1register.ThereceivemodeisselectedintheRECEIVE_MODEbitoftheCONFIG_4register.SeesectionsSingleEchoReceiveModeandMultipleEchoReceiveModefordetailsaboutthereceivermodesoftheTDC1011. AnexampleforNUM_RX=2handRECEIVE_MODE=0isshowninFigure22.WhentheechosignalamplitudeexceedsvaluessmallerthanVTHLD,thethresholdparatorindicatestotheeventmanagertoqualifythenextzero-crosseventasvalid.Whenthequalifiedzero-crossisdetectedbythezero-crossparator,theeventmanagerpassesthepulsetotheSTOPpinuntilthenumberofreceiveeventsprogrammedinNUM_RXisreached. STOP COMPIN VCOMVTHLD GND PassesVTHLD PassesVTHLD Qualifiedforzero-cross Qualifiedforzero-cross Figure22.SignalQualification,Zero-crossDetectionandSTOPPulseGeneration 16 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 8.3.7Common-modeBuffer(VCOM) Theoutputofthemon-modebufferispresentattheVCOMpin.Thispinshouldbebypassedtogroundwithalow-leakage10-nFcapacitoranditshouldnotbeloadedwithmorethan20µA.monmodebuffercanbedisabledwiththeVCOM_SELbitintheCONFIG_2register.Ifdisabled,anexternalreferencevoltagemustbeappliedtotheVCOMpin. Duringatime-of-flightmeasurement,mon-modereferencewilltakeapproximately16µstosettleifstartingfromzeroinitialconditions.Usingalargercapacitorwillincreasethesettlingtimeofthemonmodereference.TheimplicationsofalargerVCOMcapacitorarefurtherexploredintheCommon-modeReferenceSettlingTimesection. 8.3.8TemperatureSensor TDC1011 MEAS_MODE tof_start MUX START MEAS_MODE tof_ MUX STOP TempSensor RREF RTD1 RTD1(external) RTD2 RTD2(external) Figure23.TemperatureSensorMeasurement uratemeasurementsoflevel,andconcentrationmaypensationforthetemperaturedependencyofthespeedofsoundinthemedium.TheTDC1011providestwotemperaturesensorconnections,allowingtomeasureuptotwolocationswithRTDs,asshowninFigure23. ThetemperaturesensorblocksupportsPT1000orPT500sensors.ThetypeofRTDusedmustbeselectedintheTEMP_RTD_SELbitoftheCONFIG_3register.Thesystemrequiresatemperature-stableexternalreferenceresistor(RREF).IftheRTDtypeisPT500,thenRREFshouldbe500Ω.IftheRTDtypeisPT1000,thenRREFshouldbe1kΩ.Thereferenceresistorneedstohaveeitheralowtemperaturecoefficientorbecalibratedfortemperatureshift. ThelogictiminginatemperaturemeasurementiscontrolledbytheTEMP_CLK_DIVbitintheCONFIG_3register.AsshowninFigure24,theexternalclockcanbedividedby8orbythevalueresultingfromtheTX_FREQ_DIVfieldconfigurationintheCONFIG_0register.Itismendedtooperatethetemperaturemeasurementblockatfrequenciesof1MHzorless. Copyright©2015,TexasInstrumentsIncorporated 17 TDC1011-Q1 ZHCSDU8–JULY2015 CLKIN¦CLKIN 0x03[4]±TEMP_CLK_DIV O8O2TX_FREQ_DIV+
1 0 ¦TEMP
1 TTEMP=
1 ¦TEMP 0x00[7:5]±TX_FREQ_DIVFigure24.TimingSourcefortheTemperatureMeasurement 8.3.8.1TemperatureMeasurementwithMultipleRTDs ThetemperaturemeasurementmodeisselectedbysettingtheMEAS_MODEbitintheCONFIG_2registerto1.Atemperaturemeasurementisstartedbysendingatriggerpulse.Afterthetemperaturemeasurementplete,theTDC1011returnstoSLEEPmode.ToreturntoTOFmeasurementmode,resettheMEAS_MODEbitto0. ThetemperaturesensormeasurementcanbeperformedwithouttheneedofanexternalADC.Thetemperaturesensorblockoperatesbyconvertingtheresistanceofareference,RREF,anduptotwoRTDsintoaseriesofSTARTandSTOPpulses.Theintervalbetweenthepulsesisproportionaltothemeasuredresistance,andtherefore,thetemperature.AsshowninFigure25,theTDC1011performsthreemeasurementspertriggereventandgeneratesthecorrespondingpulsesontheSTARTandSTOPpins. TRIGGER Reference RTD1 RTD2 STARTSTOP td1tREF td2tRTD1 Figure25.TemperatureMeasurementOutputTiming tRTD2 TheresistanceofRTD1andRTD2canbecalculatedfromthetimeintervalsinFigure25asfollows: RRTDxRREFKtREF tRTDx
(3) Witha1-kΩreferenceresistor,thetREFintervalisapproximately200μs.Thefollowingintervals,tRTD1andtRTD2,willdependontheresistanceoftheRTDs.Thetimedelaybetweenmeasurements,td1andtd2,canbeapproximatedasfollows: td1=(51×TTEMP)+(tRTD1×0.55)
(4) td2=(51×TTEMP)+(tRTD2×0.55)
(5) Forexample,twoPT1000sensorsat0°Cwillhaveanapproximateresistanceof1kΩ;thesameasthereferenceresistorinthisexample.Givenanexternal8-MHzclockandthedefaulttemperatureclockdivide-by-8fromtheTEMP_CLK_DIVbit,theoverallmeasurementtimebetweentheSTARTpulseandthelastSTOPpulseisapproximately922µs. 18 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 8.3.8.2TemperatureMeasurementwithaSingleRTD ThetemperaturesensingblockcanbeconfiguredtomeasureasingleRTDbysettingtheTEMP_MODEbitinregisterCONFIG_3to1.WhenthetemperaturemeasurementrunsinPT1000mode(TEMP_RTD_SEL=0),thefirstintervalcorrespondstoRREF,thesecondintervalisaredundantmeasurementonRREFandshouldbeneglected,andthethirdintervalcorrespondstoRTD1.ThisoperationisrepresentedinFigure26. TRIGGER Reference Discard RTD1 STARTSTOP tREF td1 td2 ½tREF tRTD1 Figure26.TemperatureMeasurementwithaSinglePT1000 TheresistanceofRTD1canbecalculatedusingEquation3.ThetimedelaybetweenmeasurementscanbeapproximatedusingEquation4andEquation5,withtheexceptionthatinthiscase,td1isafunctionof½tREFandtd2isafunctionoftRTD1. IfthetemperaturemeasurementrunsinPT500mode(TEMP_RTD_SEL=1),thefirstintervalisaredundantmeasurementonRREFandshouldbeneglected,thesecondintervalcorrespondstoRREF,andthethirdintervalcorrespondstoRTD1.ThisoperationisrepresentedinFigure27. TRIGGER Discard Reference RTD1 STARTSTOP td1 td2 2KtREF tREF tRTD1 Figure27.TemperatureMeasurementwithaSinglePT500 TheresistanceofRTD1canbecalculatedusingEquation3.ThetimedelaybetweenmeasurementscanbeapproximatedusingEquation4andEquation5,withtheexceptionthatinthiscase,td1isafunctionoftREFandtd2isafunctionoftRTD1. 8.4DeviceFunctionDescription 8.4.1Time-of-FlightMeasurementMode TheTOFmeasurementmodeisselectedbysettingtheMEAS_MODEbitintheCONFIG_2registerto0. 8.4.1.1LiquidLevelorFluidIdentification TheTDC1011performsasingleTOFmeasurementafterreceivingatriggersignalandreturnstotheSLEEPmodewhenthemeasurementplete. 8.4.2StateMachine AstatemachineintheTDC1011managestheoperationofthevariousmeasurementmodes(seeFigure28).Atpower-on,thestatemachineisresetandmostblocksaredisabled.Afterthepower-onsequenceplete,thedevicegoesintoSLEEPmodeiftheENpinisloworintoREADYmodeiftheENpinishigh.IntheSLEEPorREADYstate,theTDC1011isabletoreceivemandstosetregistersandconfigurethedeviceforameasurementmode. Copyright©2015,TexasInstrumentsIncorporated 19 TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) NOTEAlthoughtheSPIblockisalwaysactive,itisnotmendedtoperformconfigurationchangeswhilethedeviceisactive.ConfigurationchangesshouldbeperformedwhilethedeviceisintheSLEEPstateorintheREADYstate. IftheENpinishighandatriggersignalisreceived,thestatemachinewillbegintheexecutionoftheconfiguredmeasurement.ThestatemachinewillreturntotheSLEEPstateafterthemeasurementpleted. ThedevicecanbeforcedtoexitameasurementbyapplyingalogichighontheRESETpinhighoralogiclowontheENpin. SWReset Timeout=1EN=Low HWReset SLEEPstateEN=High ERROR_FLAGSregister(0x07):NWriting1tobit[1]oftheERROR_FLAGS registercancelsanyactivemeasurementandreturnstosleepmodeorreadymodetNotandsetsCountto0andCH-flagtoFALSE. Ready Triggerpulse?
YesTXBurstOutputSTART Pulse RXActive OutputSTOPpulses Mode?
Figure28.SimplifiedTDC1011StateMachineDiagram 20 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued)8.4.3TRANSMITOperation 8.4.3.1TransmissionPulseCount ThenumberofTXpulsesgeneratedbytheTDC1011todriveanultrasonictransducerisprogrammableusingtheNUM_TXfieldlocatedintheCONFIG_0register. 8.4.3.2TX180°PulseShift AsshowninFigure29,thetransmitterblockcanadda180°shiftatapositionintheTXsignal.ThepositionofthepulseshiftissetbytheTX_PH_SHIFT_POSfieldintheCONFIG_4registerandallowsgeneratingaspecificsignalpattern. Generationof180°burstforTxSignature Figure29.TransmitterPulseSignature,180°Burst AsshowninFigure30,enablingtheTX180°pulseshifthastheeffectofdecreasingthenumberoftransmittedpulsesby1. NormalOperation:NUM_TX=0x07TX_PH_SHIFT_POS=0x1F 180|Shift:NUM_TX=0x07TX_PH_SHIFT_POS=0x03 Pos.0Pos.1Pos.2Pos.3Pos.4 Figure30.TransmitterPulseSignature Pos.5 Pos.6 Insomecases,the180°pulseshiftmayhelpimprovingtheturn-offtimeofatransducer,andthussuppressthetransmitringing. The180°pulseshiftisdisabledbysettingTX_PH_SHIFT_POStoposition31.Settingthe180°pulseshifttopositions0or1isnotmended. 8.4.3.3TransmitterDamping Thetransmitterdampingfeatureallowsforimprovedcontroloverthetransducersignalgeneration.DampingextendsthedurationofthelastTXpulsetohelpdissipateringingandimprovethetransducer'sturn-offtime(seeFigure31andFigure32).Theuracyofmeasurementscanbeimprovedbyhavingafastertransducerturn-offtime.DampingiscontrolledwiththeDAMPINGbitintheCONFIG_2register. Copyright©2015,TexasInstrumentsIncorporated 21 TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) Dampingextendsthedurationofthelastpulsetodissipateringing Figure31.TransmitterDamping(5TxPulsesWithaDampingPulse) Amplitude 8.0Dampingdisabled 6.0Dampingenabled 4.0 2.0 0.0 -2.0 -4.0 -6.0 -8.0 0.0 2.0 4.0 6.0 8.0 10.012.014.016.018.020.0 7LPH
V Figure32.TransmitterDampedEcho Therearetwoinvalidbinationsofthedampingfeaturethatmayresultinunexpectedbehavior.First,dampingshouldnotbinedwiththe180°pulseshiftdescribedintheprevioussection.Second,dampingshouldnotbeenabledifthenumberofTXpulsesissetto31. 8.4.4RECEIVEOperation 8.4.4.1SingleEchoReceiveMode SingleEchomodecanbeusedforfluididentificationmeasurementsorlevelapplicationswheretransducercarrierfrequencyinformationisrequired.ThedevicecanbeconfiguredforSingleEchomodebysettingtheRECEIVE_MODEbitto0intheCONFIG_4register.InSingleEchomode,thedevicewillgenerateSTOPpulsesforeveryzero-crossqualifiedbytheparator,uptothenumberofexpectedSTOPeventsconfiguredintheNUM_RXfieldintheCONFIG_1register. Theparatorqualifiesthenextzero-crossafteranRXamplitudesmallerthantheprogrammedthresholdvoltageisdetected.Thezero-crossdetectorwillprovideoutputpulsescorrespondingtotherisingedgeofthereceivedsignalcrossingtheVCOMlevel,asshowninFigure33.ThethresholdvoltagecanbesetintheECHO_QUAL_THDLfieldintheCONFIG_3register. 22 Copyright©2015,TexasInstrumentsIncorporated DeviceFunctionDescription(continued) Zero-crossingdetectedafterthresholdexceeded COMPIN TDC1011-Q1 ZHCSDU8–JULY2015 VCOM ECHO_QUAL_THLD Threshold Signalexceedsthreshold OutputonSTOPpin Maximumnumberofrequestedevents(5inthisfigure)returned;subsequenteventsnotreported Figure33.SingleEchoReceiveMode(5STOPEvents) IfthenumberofexpectedpulsesprogrammedinNUM_RXisnotreceivedorthetime-of-flightoperationtimesout,theTDC1011willindicateanerrorconditionintheERROR_FLAGSregisterandwillsettheERRBpinlow. 8.4.4.2MultipleEchoReceiveMode TheMultipleEchomodeisintendedforuseinlevelsensingapplicationsanddistance/displacementmeasurementsinwhichmultipleechoes(burst)arereceived.Inthiscondition,eachreceivedechogroupwillbetreatedasasinglepulseontheSTOPpin.Upto7STOPpulsescanbegeneratedbasedonthevalueoftheNUM_RXfieldintheCONFIG_1register.MultiechomodecanbeenabledbysettingtheRECEIVE_MODEbitto1intheCONFIG_4register.ArepresentationofmultipleechoSTOPpulsegenerationisshowninFigure34. COMPIN VCOMProgrammed threshold OutputonSTOPpin NopulseonSTOPpinbecausesignaldidnotexceedthreshold NopulseonSTOPpinbecausemaximumnumberofprogrammedevents(5inthisexample)alreadyproduced. Figure34.MultipleEchoReceiveMode(5STOPEvents) Copyright©2015,TexasInstrumentsIncorporated 23 TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) TherisingedgeofaSTOPpulseisgeneratedbyazero-crossingevent.AsintheSingleEchoReceiveMode,theparatorqualifiesthenextzero-crossafteranRXamplitudesmallerthantheprogrammedthresholdvoltageisdetected.TheSTOPpulsewillextenduntilazero-crossaftertheRXamplitudeisnolongersmallerthanthethresholdvoltage(seeFigure35). Zero-crossingdetectedafterthresholdexceeded Signalzero-crossingwithoutexceedingthreshold COMPIN VCOM Programmedthreshold OutputonSTOPpin Signalexceedsthreshold Figure35.MultipleEchoReceiveMode(Zoom-in) IfthenumberofexpectedpulsesprogrammedinNUM_RXisnotreceivedorthetime-of-flightoperationtimesout,theTDC1011willindicateanerrorconditionintheERROR_FLAGSregisterandwillsettheERRBpinlow. 8.4.5Timing 8.4.5.1TimingControlandFrequencyScaling(CLKIN)0x09[2]±CLOCKIN_DIV CLKIN¦CLKIN O2CLOCKIN_DIV 1¦0T0= ¦
0 O2TX_FREQ_DIV+
1 ¦
1 1T1= ¦
1 0x00[7:5]±TX_FREQ_DIVFigure36.ExternalClockDivisionTree AlltransmitandreceivefunctionsequencingissynchronoustotheexternalclockappliedtotheCLKINpin.TheexternalclockisdividedtogeneratetwointernalclockswithcorrespondingtimeperiodsdenotedasT0andT1inFigure36.ThedivisionfactorusedtogenerateT0iscontrolledwiththeCLOCKIN_DIVbitintheCLOCK_RATEregister.ThedivisionfactorusedtogenerateT1iscontrolledwiththeTX_FREQ_DIVfieldlocatedintheCONFIG_0register. TheSPIblockissynchronouswiththeclockappliedtotheSCLKpin,anditisindependentoftheclockappliedtoCLKIN.SeetheSerialPeripheralInterface(SPI)sectionforpletedescriptionoftheSPIblock. 24 Copyright©2015,TexasInstrumentsIncorporated TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) 8.4.5.2TX/RXMeasurementSequencingandTiming TheTDC1011automaticallysequencestheTXandRXfunctionality.AfterreceivingapulseedgeontheTRIGGERpin,theTDC1011resynchronizestotheCLKINsignal,andsendsaTXburst. Thetriggeredgepolarityisconfiguredtorisingedgebydefault,butitcanbechangedtofallingedgebysettingtheTRIG_EDGE_POLARITYbitintheCONFIG_4registerto1. Afteradevicereset,thesystemmustwaitadeterminedtimebeforesendingthenexttriggersignal.Thetypicalresettotriggerwaittimeis3×T1+50ns. 8.4.6Time-of-Flight(TOF)Control ThepossibleconfigurationsoftheTX/RXsequencingduringatime-of-flightmeasurementcanbedividedintothreecases:ShortTOFMeasurement,StandardTOFMeasurementandStandardTOFMeasurementwithPowerBlanking.Overall,thecasesdifferintheorderofsequencing,powersavingandecholisteningwindows.Thebehaviorofeachcaseisdescribedinthesectionstofollow. 8.4.6.1ShortTOFMeasurement TRIG (seeNoteA) AnalogOFFAnalogONEcholistenperiod TX STARTRX (seeNoteC) (seeNoteB) STOP READY COMMON-MODE128xT0 AUTOZERO2AUTOZERO_PERIODx64xT0 TRANSMITNUM_TXxT1 MASK2SHORT_TOF_BLANK_PERIODx8xT0 ECHOLISTEN2TOF_TIMEOUT_CTRLx128xT0 ENDREADY1xT1
A.Common-modesettlingtime.B.IfNUM_TX<3,thewidthoftheSTARTpulseisequaltoNUM_TX×T1.IfNUM_TX≥3,thewidthoftheSTART pulseisequalto3×T1. Figure37.ShortTOFMeasurement Inashorttimeofflightmeasurement,theRXpathisactivatedbeforetheTXburst,asshowninFigure37. TheshortTOFisthedefaultmeasurementsequenceselectedatpower-on.TheshortTOFmeasurementisselectedifthevalueoftheTIMING_REG[9:0]fieldislessthan30,oriftheFORCE_SHORT_TOFbitissetto1.TheTIMING_REG[9:0]isa10-bitwidefield,withits2mostsignificantbitslocatedintheTOF_1register,andthe8leastsignificantbitslocatedintheTOF_0register.TheFORCE_SHORT_TOFbitislocatedintheTIMEOUTregister. parator'sinputoffsetisstoredinaninternalcapacitorduringtheauto-zeroperiod.Thelengthoftheauto-zeroperiodiscontrolledbytheAUTOZERO_PERIODfieldintheCLOCK_RATEregister. Copyright©2015,TexasInstrumentsIncorporated 25 TDC1011-Q1 ZHCSDU8–JULY2015 DeviceFunctionDescription(continued) ThelengthofthewindowwhenparatorsareabletoqualifyandgenerateSTOPpulsesisconfiguredbytheTOF_TIMEOUT_CTRLfield.Atimeoutwillurifthenumberofexpectedpulsesisnotreceivedduringtheallocatedtimeandanerrorconditionisrep
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