Data Sheet
AD7798/AD7799
Rev. B | Page 3 of 28
SPECIFICATIONS
AVDD = 2.7 V to 5.25 V; DVDD = 2.7 V to 5.25 V; GND = 0 V; REFIN(+) = AVDD; REFIN() = 0 V. All specifications TMIN to TMAX, unless
otherwise noted.
Table 1.
Parameter
Unit
Test Conditions/Comments
ADC CHANNEL
Output Update Rate
4.17 470
Hz nom
24
Bits min
AD7799: fADC < 242 Hz
16
Bits min
AD7798
Resolution
Output Noise and Update Rates
Integral Nonlinearity
±15
ppm of FSR max
±1
V typ
Offset Error Drift vs. Temperatur
e4±10
nV/°C typ
±10
V typ
Gain Drift vs. Temperatur
e4±1
ppm/°C typ
Power Supply Rejection
100
dB min
AIN = 1 V/gain, gain ≥ 4
ANALOG INPUTS
Differential Input Voltage Ranges
±VREF/gain
V nom
VREF = REFIN(+) – REFIN(–), gain = 1 to 128
Absolute AIN Voltage Limi
ts2Unbuffered Mode
GND 30 mV
V min
Gain = 1 or 2
AVDD + 30 mV
V max
Buffered Mode
GND + 100 mV
V min
Gain = 1 or 2
AVDD – 100 mV
V max
In-Amp Active
GND + 300 mV
V min
Gain = 4 to 128
AVDD 1.1
V max
Common-Mode Voltage, VCM
0.5
V min
VCM = (AIN(+) + AIN())/2, gain = 4 to 128
Analog Input Current
Buffered Mode or In-Amp Active
±1
nA max
Gain = 1 or 2, update rate < 100 Hz
±250
pA max
Gain = 4 to 128, update rate < 100 Hz
±1
nA max
AIN3(+)/AIN3(), update rate < 100 Hz
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
@ 50 Hz, 60 Hz
65
dB min
80 dB typ, 50 ± 1 Hz, 60 ± 1 Hz (FS[3:0] = 1010)
6@ 50 Hz
80
dB min
90 dB typ, 50 ± 1 Hz (FS[3:0] = 10
01)6@ 60 Hz
90
dB min
100 dB typ, 60 ± 1 Hz (FS[3:0] = 1000
)6Common-Mode Rejection
@ DC
100
dB min
AIN = 1 V/gain, gain ≥ 4
100
dB min
50 ± 1 Hz, 60 ± 1 Hz (FS[3:0] = 10
10)6100
dB min
50 ± 1 Hz (FS[3:0] = 100
16), 60 ± 1 Hz