Datasheet

AD7794/AD7795
Rev. D | Page 4 of 36
Parameter
1
AD7794/AD7795 Unit Test Conditions/Comments
Common-Mode Rejection
AD7794B/AD7795B
@ DC 100 dB min AIN = 1 V/gain, gain ≥ 4
@ 50 Hz, 60 Hz
2
100 dB min 50 ± 1 Hz, 60 ± 1 Hz, FS[3:0] = 1010
@ 50 Hz, 60 Hz
2
100 dB min 50 ± 1 Hz, FS[3:0] = 1001; 60 ± 1 Hz, FS[3:0] = 1000
AD7794C
@ DC 97 dB min AIN = 1 V/gain, gain ≥ 4
@ 50 Hz, 60 Hz
2
97 dB min 50 ± 1 Hz, 60 ± 1 Hz, FS[3:0] = 1010
@ 50 Hz, 60 Hz
2
97 dB min 50 ± 1 Hz, FS[3:0] = 1001; 60 ± 1 Hz, FS[3:0] = 1000
CHOP DISABLED
Output Update Rate 4.17 to 470 Hz nom Settling time = 1/output update rate
No Missing Codes
2
AD7794 24 Bits min f
ADC
≤ 123 Hz
AD7795 16 Bits min
Resolution See the RMS Noise and Resolution Specifications section
RMS Noise and Update Rates See the RMS Noise and Resolution Specifications section
Integral Nonlinearity ±15
ppm of FSR
max
Offset Error
3
±100/gain μV typ Without calibration
Offset Error Drift vs. Temperature
4
±100/gain nV/°C typ Gain = 1 to 16
10 nV/°C typ Gain = 32 to 128
Full-Scale Error
3, 5
±10 μV typ
Gain Drift vs. Temperature
4
±1 ppm/°C typ Gain = 1 to 16, external reference
±3 ppm/°C typ Gain = 32 to 128, external reference
Power Supply Rejection 100 dB typ AIN = 1 V/gain, gain ≥ 4, external reference
ANALOG INPUTS
Differential Input Voltage Ranges ±V
REF
/gain V nom
V
REF
= REFIN(+) − REFIN(−), or internal reference,
gain = 1 to 128
Absolute AIN Voltage Limits
2
Unbuffered Mode GND − 30 mV V min Gain = 1 or 2
AV
DD
+ 30 mV V max
Buffered Mode GND + 100 mV V min Gain = 1 or 2
AV
DD
− 100 mV V max
In-Amp Active GND + 300 mV V min Gain = 4 to 128
AV
DD
− 1.1 V max
Common-Mode Voltage, V
CM
0.2 + (gain/2 × (AIN(+) −
AIN(−)))
V min AMP − CM = 1, VCM = (AIN(+) + AIN(–))/2, gain = 4 to 128
AV
DD
− 0.2 − (gain/2 ×
(AIN(+) − AIN(−)))
V max
Analog Input Current
Buffered Mode or In-Amp
Active
Average Input Current
2
AD7794B/AD7795B ±1 nA max Gain = 1 or 2
±250 pA max Gain = 4 to 128
±1 nA max AIN6(+)/AIN6(−)
AD7794C ±3 nA max Gain = 1 or 2
±2 nA max Gain = 4 to 128
±3 nA max AIN6(+)/AIN6(−)
Average Input Current Drift ±2 pA/°C typ
Unbuffered Mode Gain = 1 or 2
Average Input Current ±400 nA/V typ Input current varies with input voltage
Average Input Current Drift ±50 pA/V/°C typ