AD7788/AD7789 Data Sheet
Rev. C | Page 4 of 20
AD7788
V
DD
= 2.5 V to 5.25 V (B grade); V
DD
= 2.7 V to 5.25 V (A grade); REFIN(+) = 2.5 V; REFIN(−) = GND; GND = 0 V; all specifications
T
MIN
to T
MAX
, unless otherwise noted.
Table 2.
Parameter
1
AD7788A, AD7788B Unit Test Conditions/Comments
ADC CHANNEL SPECIFICATION
Output Update Rate 16.6 Hz nom
ADC CHANNEL
No Missing Codes
2
16 Bits min
Resolution 16 Bits p-p
Output Noise 1.5 µV rms typ
Integral Nonlinearity ±15 ppm of FSR max B grade
Offset Error ±3 µV typ
Offset Error Drift vs. Temperature ±10 nV/°C typ
Full-Scale Error
3
±10 µV typ
Gain Drift vs. Temperature ±0.5 ppm/°C typ
Power Supply Rejection 90 dB min B grade
90 dB typ A grade
ANALOG INPUTS
Differential Input Voltage Ranges ±REFIN V nom REFIN = REFIN(+) − REFIN(−)
Absolute AIN Voltage Limits
2
GND − 30 mV V min
V
DD
+ 30 mV V max
Analog Input Current
Input current varies with input
voltage
Average Input Current
2
±400 nA/V typ
Average Input Current Drift
Normal-Mode Rejection
2
At 50 Hz, 60 Hz 65 dB min B grade, 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
60 dB min A grade, 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
Common-Mode Rejection AIN = 1 V
At DC 90 dB min B grade, 100 dB typ
90 dB typ A grade
At 50 Hz, 60 Hz
2
100 dB min B grade, 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
100 dB typ A grade, 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
REFERENCE INPUT
REFIN Voltage 2.5 V nom REFIN = REFIN(+) − REFIN(−)
Reference Voltage Range
2
0.1 V min
V
DD
V max
Absolute REFIN Voltage Limits
2
GND − 30 mV V min
DD
Average Reference Input Current 0.5 µA/V typ
Average Reference Input Current Drift ±0.03 nA/V/°C typ
Normal-Mode Rejection
2
At 50 Hz, 60 Hz 65 dB min B grade, 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
60 dB min A grade
Common-Mode Rejection AIN = 1 V
At DC 100 dB typ
At 50 Hz, 60 Hz 110 dB typ 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
1
Temperature range: B grade: −40°C to +105°C; A grade: −40°C to +85°C.
2
Specification is not production tested but is supported by characterization data at initial product release.
3
Full-scale error applies to both positive and negative full scale and applies at the factory calibration conditions (V
DD
= 4 V).