Datasheet AD7796, AD7797 (Analog Devices) - 3

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Data Sheet AD7796/AD7797 SPECIFICATIONS
AVDD = 2.7 V to 5.25 V, DVDD = 2.7 V to 5.25 V, GND = 0 V, all specifications TMIN to TMAX, unless otherwise noted.
Table 1. Parameter AD7796B/ AD7797B1 Unit Test Conditions/Comments
ADC CHANNEL Output Update Rate 4.17 to 123 Hz nom No Missing Codes2 24 Bits min AD7797 only 16 Bits min AD7796 only Resolution See Table 7 and Table 8 RMS Noise and Update Rates See Table 6 Integral Nonlinearity ±10 ppm of FSR typ Offset Error3, 4 ±1 µV typ Offset Error Drift vs. Temperature4 ±10 nV/°C typ Full-Scale Error3, 4, 5 ±10 µV typ Gain Drift vs. Temperature4 ±3 ppm/°C typ Power Supply Rejection 90 dB min AIN = 1 V/128 ANALOG INPUTS Differential Input Voltage Ranges ±VREF/128 V nom VREF = REFIN(+) – REFIN(–) Absolute AIN Voltage Limits2 GND + 300 mV V min AVDD − 1.1 V max Common-Mode Voltage, VCM 0.5 V min VCM = (AIN(+) + AIN(–))/2 Analog Input Current Average Input Current2 ±250 pA max Update rate < 100 Hz Average Input Current Drift ±2 pA/°C typ Normal Mode Rejection2 Internal Clock At 50 Hz, 60 Hz 65 dB min 80 dB typ, 50 ± 1 Hz, 60 ± 1 Hz, FS[3:0] = 10106 At 50 Hz 80 dB min 90 dB typ, 50 ± 1 Hz, FS[3:0] = 10016 At 60 Hz 90 dB min 100 dB typ, 60 ± 1 Hz, FS[3:0] = 10006 External Clock At 50 Hz, 60 Hz 80 dB min 90 dB typ, 50 ± 1 Hz, 60 ± 1 Hz, FS[3:0] = 10106 At 50 Hz 94 dB min 100 dB typ, 50 ± 1 Hz, FS[3:0] = 10016 At 60 Hz 90 dB min 100 dB typ, 60 ± 1 Hz, FS[3:0] = 10006 Common-Mode Rejection At DC 90 dB min AIN = 7.81 mV At 50 Hz, 60 Hz2 90 dB min 50 ± 1 Hz, 60 ± 1 Hz, FS[3:0] = 10106 At 50 Hz, 60 Hz2 90 dB min 50 ± 1 Hz (FS[3:0] = 10016), 60 ± 1 Hz, FS[3:0] = 10006 REFERENCE External REFIN Voltage 2.5 V nom REFIN = REFIN(+) – REFIN(–) Reference Voltage Range2 0.1 V min AVDD V max Absolute REFIN Voltage Limits2 GND − 30 mV V min AVDD + 30 mV V max Average Reference Input Current 400 nA/V typ Average Reference Input Current Drift ±0.03 nA/V/°C typ Normal Mode Rejection Same as for analog inputs Common-Mode Rejection 100 dB typ TEMPERATURE SENSOR Accuracy ±2 °C typ Applies if user calibrates the temperature sensor Sensitivity 0.81 mV/°C typ Rev. B | Page 3 of 24 Document Outline FEATURES INTERFACE APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS TIMING DIAGRAMS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS RMS NOISE AND RESOLUTION SPECIFICATIONS TYPICAL PERFORMANCE CHARACTERISTICS ON-CHIP REGISTERS COMMUNICATION REGISTER RS2, RS1, RS0 = 0, 0, 0 STATUS REGISTER RS2, RS1, RS0 = 0, 0, 0; Power-On/Reset = 0x80 MODE REGISTER RS2, RS1, RS0 = 0, 0, 1; Power-On/Reset = 0x000A CONFIGURATION REGISTER RS2, RS1, RS0 = 0, 1, 0; Power-On/Reset = 0x0710 DATA REGISTER RS2, RS1, RS0 = 0, 1, 1; Power-On/Reset = 0x0000 (AD7796)/0x000000 (AD7797) ID REGISTER RS2, RS1, RS0 = 1, 0, 0; Power-On/Reset = 0x5A (AD7796)/0x5B (AD7797) OFFSET REGISTER RS2, RS1, RS0 = 1, 1, 0; Power-On/Reset = 0x8000 (AD7796)/0x800000 (AD7797) FULL-SCALE REGISTER RS2, RS1, RS0 = 1, 1, 1; Power-On/Reset = 0x5XXX (AD7796)/0x5XXX00 (AD7797) ADC CIRCUIT INFORMATION OVERVIEW DIGITAL INTERFACE Single Conversion Mode Continuous Conversion Mode Continuous Read Mode CIRCUIT DESCRIPTION ANALOG INPUT CHANNEL BIPOLAR/UNIPOLAR CONFIGURATION DATA OUTPUT CODING REFERENCE RESET BURNOUT CURRENTS AVDD MONITOR TEMPERATURE MONITOR CALIBRATION GROUNDING AND LAYOUT APPLICATIONS INFORMATION WEIGH SCALES OUTLINE DIMENSIONS ORDERING GUIDE