ADS7844: 12-Bit, 8-Channel Serial Output Sampling …

1 ADS784412-Bit, 8-Channel Serial Output SamplingANALOG-TO-DIGITAL CONVERTERFEATURES SINGLE SUPPLY: to 5V 8-Channel SINGLE-ENDED OR4- channel DIFFERENTIAL INPUT UP TO 200kHz CONVERSION RATE 1 LSB MAX INL AND DNL NO MISSING CODES 72dB SINAD Serial INTERFACE 20-LEAD QSOP AND20-LEAD SSOP PACKAGES ALTERNATE SOURCE FOR MAX147 DESCRIPTIONThe ADS7844 is an 8-Channel , 12-bit Sampling analog -to-digital converter (ADC) with a synchronous Serial power dissipation is 3mW at a 200kHz throughputrate and a +5V supply.

2 The reference voltage (VREF) can bevaried between 100mV and VCC, providing a correspondinginput voltage range of 0V to VREF. The device includes ashutdown mode that reduces power dissipation to under1 W. The ADS7844 is ensured down to power, high speed, and onboard multiplexer make theADS7844 ideal for battery-operated systems such as personaldigital assistants, portable multichannel data loggers, andmeasurement equipment. The Serial interface also provideslow-cost isolation for remote data acquisition.

3 The ADS7844is available in a 20-lead QSOP package and the MAX147equivalent 20-lead SSOP package and is ensured over the 40 C to +85 C temperature DATA ACQUISITION TEST AND MEASUREMENT INDUSTRIAL PROCESS CONTROL PERSONAL DIGITAL ASSISTANTS BATTERY-POWERED SYSTEMSCDACSARC omparatorEightChannelMultiplexerSerialIn terfaceandControlCH4CH5CH6CH7 COMVREFCH0CH1CH2CH3 CSSHDNDINDOUTBUSYDCLKADS7844 ADS7844 SBAS100A JANUARY 1998 REVISED OCTOBER DATA information is current as of publication conform to specifications per the terms of Texas Instrumentsstandard warranty.

4 Production processing does not necessarily includetesting of all 1998-2003, Texas Instruments IncorporatedPlease be aware that an important notice concerning availability, standard warranty, and use in critical applications ofTexas Instruments semiconductor products and disclaimers thereto appears at the end of this data trademarks are the property of their respective : +5 VAt TA = 40 C to +85 C, +VCC = +5V, VREF = +5V, fSAMPLE = 200kHz, and fCLK = 16 fSAMPLE = , unless otherwise , NADS7844EB, NBPARAMETERCONDITIONSMINTYPMAXMINTYPMAXU NITSANALOG INPUTFull-Scale Input SpanPositive Input - Negative Input0 VREF VAbsolute Input RangePositive Input +VCC + VNegative Input + VCapacitance25 pFLeakage Current 1 ASYSTEM PERFORMANCER esolution12 BitsNo Missing Codes12 BitsIntegral Linearity Error 2 1 LSB(1)

5 Differential Linearity Error 1 LSBO ffset Error 3 LSBO ffset Error LSBGain Error 4 3 LSBGain Error LSBN oise30 VrmsPower Supply Rejection70 dBSAMPLING DYNAMICSC onversion Time12 Clk CyclesAcquisition Time3 Clk CyclesThroughput Rate200 kHzMultiplexer Settling Time500 nsAperture Delay30 nsAperture Jitter100 psDYNAMIC CHARACTERISTICST otal Harmonic Distortion(2)VIN = 5 VPP at 10kHz 76 78dBSignal-to-(Noise + Distortion)VIN = 5 VPP at 10kHz7172dBSpurious Free Dynamic RangeVIN = 5 VPP at 10kHz7678dBChannel-to- channel IsolationVIN = 5 VPP at 50kHz120 dBREFERENCE +VCC VResistanceDCLK Static5 G Input Current45100 AfSAMPLE = ADCLK ADIGITAL INPUT/OUTPUTL ogic FamilyCMOS Logic LevelsVIH| IIH | +5 VVIL| IIL | +5 A + VVOHIOH = 250 VVOLIOL = 250 VData FormatStraight Binary POWER SUPPLY REQUIREMENTS+VCCS pecified VQuiescent Current550900 AfSAMPLE = APower-Down Mode(3)

6 , CS = +VCC3 APower mWTEMPERATURE RANGES pecified Performance 40+85 C Same specifications as ADS7844E, : (1) LSB means Least Significant Bit. With VREF equal to + , one LSB is (2) First five harmonics of the test frequency. (3) Auto power-down mode(PD1 = PD0 = 0) active or SHDN = : + TA = 40 C to +85 C, +VCC = + , VREF = + , fSAMPLE = 125kHz, and fCLK = 16 fSAMPLE = 2 MHz, unless otherwise , NADS7844EB, NBPARAMETERCONDITIONSMINTYPMAXMINTYPMAXU NITSANALOG INPUTFull-Scale Input SpanPositive Input - Negative Input0 VREF VAbsolute Input RangePositive Input +VCC + VNegative Input + VCapacitance25 pFLeakage Current 1 ASYSTEM PERFORMANCER esolution12 BitsNo Missing Codes12 BitsIntegral Linearity Error 2 1 LSB(1)

7 Differential Linearity Error 1 LSBO ffset Error 3 LSBO ffset Error LSBGain Error 4 3 LSBGain Error LSBN oise30 VrmsPower Supply Rejection70 dBSAMPLING DYNAMICSC onversion Time12 Clk CyclesAcquisition Time3 Clk CyclesThroughput Rate125 kHzMultiplexer Settling Time500 nsAperture Delay30 nsAperture Jitter100 psDYNAMIC CHARACTERISTICST otal Harmonic Distortion(2)VIN = at 10kHz 75 77dBSignal-to-(Noise + Distortion)VIN = at 10kHz7172dBSpurious Free Dynamic RangeVIN = at 10kHz7880dBChannel-to- channel IsolationVIN = at 50kHz100 dBREFERENCE +VCC VResistanceDCLK Static5 G Input Current1340 AfSAMPLE = ADCLK ADIGITAL INPUT/OUTPUTL ogic FamilyCMOS Logic LevelsVIH| IIH | +5 A+VCC VVIL| IIL | +5 A + VVOHIOH = 250 A+VCC VVOLIOL = 250 VData FormatStraight Binary POWER SUPPLY REQUIREMENTS+VCCS pecified VQuiescent Current280650 AfSAMPLE = APower-Down Mode(3)

8 , CS = +VCC3 APower mWTEMPERATURE RANGES pecified Performance 40+85 C Same specifications as ADS7844E, : (1) LSB means Least Significant Bit. With VREF equal to + , one LSB is 610mV. (2) First five harmonics of the test frequency. (3) Auto power-down mode(PD1 = PD0 = 0) active or SHDN = CONFIGURATIONTop ViewPIN DESCRIPTIONSPINNAMEDESCRIPTION1CH0 analog Input channel Input channel Input channel Input channel Input channel Input channel Input channel Input channel reference for analog inputs.

9 Sets zero codevoltage in single ended mode. Connect this pin to groundor ground reference When LOW, the device enters a very lowpower shutdown Reference Input. See Specification Table +VCCP ower Supply, to Data Output . Data is shifted on the falling edge ofDCLK. This Output is high impedance whenCS is Output . Busy goes low when the DIN control bitsare being read and also when the device is Output is high impedance when CS is Data Input. If CS is LOW, data is latched on risingedge of Select Input.

10 Active LOW. Data will not be clockedinto DIN unless CS is low. When CS is high DOUT is Clock Input. The clock speed determines theconversion rate by the equation fCLK = 16 +VCCP ower Supply12345678910CH0CH1CH2CH3CH4CH5CH6CH 7 COMSHDN+VCCDCLKCSDINBUSYDOUTGNDGND+VCCVR EF20191817161514131211 ADS7844 MINIMUMRELATIVEMAXIMUMSPECIFIEDACCURACYG AIN ERROR TEMPERATUREPACKAGEORDERINGTRANSPORTPRODU CT(LSB)(LSB)RANGEPACKAGE-LEADDESIGNATORN UMBERMEDIA, QUANTITYADS7844E 2 4 40 C to +85 CQSOP-20 DBQADS7844 ERails, 56""""""ADS7844E/2K5 Tape and Reel, 2500 ADS7844N"""SSOP-20 DBADS7844 NRails, 68""""""ADS7844N/1 KTape and Reel,1000 ADS7844EB 1 3 40 C to +85 CQSOP-20 DBQADS7844 EBRails, 56""""""ADS7844EB/2K5 Tape and Reel, 2500 ADS7844NB"""SSOP-20 DBADS7844 NBRails, 68""""""ADS7844NB/1 KTape and Reel, 1000 NOTES.