Datasheet
AD7794/AD7795
Rev. D | Page 5 of 36
Parameter
1
AD7794/AD7795 Unit Test Conditions/Comments
Normal Mode Rejection
2,
6
Internal Clock
@ 50 Hz, 60 Hz 60 dB min 70 dB typ, 50 ± 1 Hz, 60 ± 1 Hz, FS[3:0] = 1010
@ 50 Hz 78 dB min 90 dB typ, 50 ± 1 Hz, FS[3:0] = 1001
@ 60 Hz 86 dB min 100 dB typ, 60 ± 1 Hz, FS[3:0] = 1000
External Clock
@ 50 Hz, 60 Hz 60 dB min 70 dB typ, 50 ± 1 Hz, 60 ± 1 Hz, FS[3:0] = 1010
@ 50 Hz 94 dB min 100 dB typ, 50 ± 1 Hz, FS[3:0] = 1001
@ 60 Hz 90 dB min 100 dB typ, 60 ± 1 Hz, FS[3:0] = 1000
Common-Mode Rejection
AD7794B/AD7795B
@ DC 100 dB min AIN = 1 V/gain, with gain = 4, AMP-CM Bit = 1
@ 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, with gain = 4, AMP-CM Bit = 1
@ 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 ENABLED or DISABLED
REFERENCE INPUT
Internal Reference
Internal Reference Initial
Accuracy
1.17 ± 0.01% V min/max AV
DD
= 4 V, T
A
= 25°C
Internal Reference Drift
2
4 ppm/°C typ
15 ppm/°C max
Power Supply Rejection 85 dB typ
External Reference
External REFIN Voltage 2.5 V nom REFIN = REFIN(+) − REFIN(−)
Reference Voltage Range
2
0.1 V min
AV
DD
V max
When V
REF
= AV
DD
, the differential input must be
limited to 0.9 × V
REF
/gain if the in-amp is active
Absolute REFIN Voltage Limits
2
GND − 30 mV V min
AV
DD
+ 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
2
Same as for analog inputs
Common-Mode Rejection 100 dB typ
Reference Detect Levels 0.3 V min
0.65 V max NOXREF bit active if V
REF
< 0.3 V
EXCITATION CURRENT SOURCES
(IEXC1 and IEXC2)
Output Current 10/210/1000 μA nom
Initial Tolerance at 25°C ±5 % typ
Drift 200 ppm/°C typ
Current Matching ±0.5 % typ Matching between IEXC1 and IEXC2, V
OUT
= 0 V
Drift Matching 50 ppm/°C typ
Line Regulation (AV
DD
) 2 %/V typ AV
DD
= 5 V ± 5%
Load Regulation 0.2 %/V typ
Output Compliance AV
DD
− 0.65 V max Current sources programmed to 10 μA or 210 μA
AV
DD
− 1.1 V max Current sources programmed to 1 mA
GND − 30 mV V min