ADS1112 16-Bit Analog-to-Digital Converter with Input ...

1 FEATURESDCOMPLETE DATA ACQUISITION SYSTEM INTHE MSOP-10 AND LEADLESS QFN-STYLEPACKAGESDMEASUREMENTS FROM TWO DIFFERENTIALCHANNELS OR THREE SINGLE-ENDEDCHANNELSDI2C INTERFACE EIGHT ADDRESSES PIN-SELECTABLEDONBOARD REFERENCE:Accuracy: : 5ppm/ CDONBOARD PGADONBOARD OSCILLATORD16 BITS, NO MISSING CODESDINL: of FSR maxDCONTINUOUS SELF-CALIBRATIONDSINGLE-CYCLE CONVERSIONDPROGRAMMABLE DATA RATE: 15 SPS to240 SPSDPOWER SUPPLY: to CURRENT CONSUMPTION: 240 AAPPLICATIONSDPORTABLE INSTRUMENTATIONDINDUSTRIAL PROCESS CONTROLDSMART TRANSMITTERSDCONSUMER GOODSDFACTORY AUTOMATIONDTEMPERATURE MEASUREMENTDESCRIPTIONThe ADS1112 is a precision, continuously self-calibratingAnalog-to-Digital (A/D) Converter with two differential or threesingle-ended channels and up to 16 bits of resolution in thesmall MSOP-10 and leadless QFN-style (small-outline,no-lead) packages.

2 The onboard reference providesan Input range of differentially. The ADS1112 usesan I2C-compatible serial interface and has two address pinsthat allow a user to select one of the eight I2C Slaveaddresses. The ADS1112 operates from a single powersupply ranging from to ADS1112 can perform conversions at rates of 15, 30, 60,or 240 samples per second (SPS). The onboardprogrammable gain amplifier (PGA), which offers gains of upto eight, allows smaller signals to be measured with highresolution. In single-conversion mode, the ADS1112automatically powers down after a conversion, greatlyreducing current consumption during idle ADS1112 is designed for applications requiringhigh-resolution measurement, where space and powerconsumption are major considerations.

3 Typical applicationsinclude portable instrumentation, industrial process control,and smart trademarks are the property of their respective JUNE 2003 REVISED MARCH 200416-Bit Analog-to-Digital Converter withInput Multiplexer and Onboard 2003 2004, Texas Instruments IncorporatedPlease be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instrumentssemiconductor products and disclaimers thereto appears at the end of this data sheet. ! ! "###$SBAS282D JUNE 2003 REVISED MARCH MAXIMUM RATINGS(1)VDD to GND to +6 VInput Current100mA, MomentaryInput Current10mA, ContinuousAnalog Inputs, A0, A1, Voltage to GND to VDD + , SCL Voltage to GND to 6 VMaximum Junction Temperature+150 COperating Temperature Range 40 C to +125 CStorage Temperature Range 60 C to +150 CLead Temperature (soldering, 10s)+300 C(1)Stresses above those listed under Absolute Maximum Ratingsmay cause permanent damage to the device.

4 Exposure toabsolute maximum conditions for extended periods may affectdevice integrated circuit can be damaged by Instruments recommends that allintegrated circuits be handled with appropriateprecautions. Failure to observe proper handling andinstallation procedures can cause damage can range from subtle performance degradationto complete device failure. Precision integrated circuits maybe more susceptible to damage because very smallparametric changes could cause the device not to meet itspublished INFORMATIONPRODUCTPACKAGE-LEADPACKAGEDES IGNATOR(1)SPECIFIEDTEMPERATURERANGEPACKA GEMARKINGORDERING NUMBERTRANSPORT MEDIA,QUANTITYADS1112 MSOP-10 DGS 40 C to +85 CBHUADS1112 IDGSTTape and Reel, 250 ADS1112 MSOP-10 DGS 40 C to +85 CBHUADS1112 IDGSRTape and Reel, 2500 ADS1112 SON-10 DRC 40 C to +85 CBHVADS1112 IDRCTTape and Reel, 250 ADS1112 SON-10 DRC 40 C to +85 CBHVADS1112 IDRCRTape and Reel, 3000(1)

5 For the most current specification and package information, refer to our web site at ViewMSOP-10 Top ViewSON-10 Terminal Channel 1; Positive InputSingle-ended Channel 1 InputAIN12 Differential Channel 1; Negative InputSingle-ended Channel 2 InputGND3 GroundAIN24 Differential Channel 2; Positive InputSingle-ended Channel 3 InputAIN35 Differential Channel 2; Negative InputSingle-ended Common InputVDD6 Power Supply: to Data: Transmits and receivesdataSCL8 Serial Clock Input : Clocks outputdata on SDAA09I2C Slave Address SelectA110I2C Slave Address Select "###$SBAS282D JUNE 2003 REVISED MARCH CHARACTERISTICS All specifications at 40 C to +85 C, VDD = 5V, and all PGAs, unless otherwise INPUTFull-Scale Input Voltage(VIN+) (VIN )

6 Input VoltageVIN+ to GND or VIN to GNDGND + Input Common-Mode Input ImpedancePGA = PGA = PGA = PGA = SYSTEM PERFORMANCER esolution and No Missing CodesDR = 001212 BitsResolution and No Missing CodesDR = 011414 BitsDR = 101515 BitsDR = 111616 BitsData RateDR = 00180240308 SPSData RateDR = 01456077 SPSDR = 10223039 SPSDR = 11111520 SPSO utput NoiseSee Typical Characteristic CurvesIntegral NonlinearityDR = 11, PGA = 1, End Point Fit(1) of FSR(2)Offset ErrorPGA = ErrorPGA = = = DriftPGA = V/ COffset DriftPGA = V/ CPGA = V/ CPGA = V/ COffset vs VDDPGA = 1800 V/VOffset vs VDDPGA = 2400 V/VPGA = 4200 V/VPGA = 8150 V/VChannel Offset MatchMatch between any two channels30 VGain Error(3) Gain Error Match(3)Match between any two PGA Error Drift(3)

7 540ppm/ CGain vs VDD80ppm/VChannel Gain MatchMatch between any two RejectionAt DC and PGA = 895105dBCommon-Mode RejectionAt DC and PGA = 1100dBDIGITAL Input /OUTPUTL ogic VDD6 VVILGND VDDVVOLIOL = LeakageIHVIH = AILVIL = GND 10 APOWER-SUPPLY REQUIREMENTSP ower-Supply ASupply CurrentActive Mode240350 APower DissipationVDD = DissipationVDD = (1)99% of full-scale.(2)FSR = full-scale range = 2 = (3)Includes all errors from onboard PGA and reference. "###$SBAS282D JUNE 2003 REVISED MARCH CHARACTERISTICSAt TA = 25 C and VDD = 5V, unless otherwise noted. "###$SBAS282D JUNE 2003 REVISED MARCH CHARACTERISTICS (continued)At TA = 25 C and VDD = 5V, unless otherwise noted.

8 "###$SBAS282D JUNE 2003 REVISED MARCH CHARACTERISTICS (continued)At TA = 25 C and VDD = 5V, unless otherwise OF OPERATIONThe ADS1112 is a 16-Bit , self-calibrating, delta-sigma A/Dconverter with an Input multiplexer. Extremely easy to de-sign with and configure, the ADS1112 allows precise mea-surements to be obtained with a minimum of ADS1112 consists of a delta-sigma A/D convertercore with adjustable gain, a reference, a clock os-cillator, and an I2C interface. Each of these blocks are de-scribed in detail in the sections that CONVERTERThe ADS1112 A/D Converter core consists of a differentialswitched-capacitor delta-sigma modulator followed by adigital filter.

9 The modulator measures the voltage differ-ence between the positive and negative analog inputs se-lected by the Input multiplexer and compares it to a refer-ence voltage, which, in the ADS1112 , is The digitalfilter receives a high-speed bitstream from the modulatorand outputs a code, which is a number proportional to theinput ADS1112 has an Input multiplexer that provides fortwo differential or three single-ended Input channels. Twobits in the configuration register control the REFERENCEThe ADS1112 contains an onboard voltage refer-ence. This reference is always used as the ADC voltagereference; an external reference cannot be ADS1112 voltage reference is internal only, and can-not be measured directly or used by external onboard reference specifications are part of the over-all gain and drift specifications of the ADS1112 .

10 The con-verter drift and gain error specifications reflect the perfor-mance of the onboard reference as well as theperformance of the A/D Converter core. There are no sepa-rate specifications for the onboard reference CODE CALCULATIONThe output code is a scaled value that is proportional, ex-cept for clipping, to the voltage difference between the twoanalog inputs. The output code is confined to a finite rangeof numbers; this range depends on the number of bitsneeded to represent the code. The number of bits neededto represent the output code for the ADS1112 depends onthe data rate, as shown in Table RATENUMBER OFBITSMINIMUMCODEMAXIMUMCODE15 SPS16 32,76832,76730 SPS15 16,38416,38360 SPS14 81928191240 SPS12 20482047 Table 1.