Datasheet

AD7788/AD7789
Rev. B | Page 3 of 20
SPECIFICATIONS
AD7789
V
DD
= 2.5 V to 5.25 V; REFIN(+) = 2.5 V; REFIN(−) = GND; GND = 0 V; all specifications T
MIN
to T
MAX
, unless otherwise noted.
Table 1.
Parameter
1
AD7789B Unit Test Conditions/Comments
ADC CHANNEL SPECIFICATION
Output Update Rate 16.6 Hz nom
ADC CHANNEL
No Missing Codes
2
24 Bits min
Resolution 19 Bits p-p
Output Noise 1.5 μV rms typ
Integral Nonlinearity ±15 ppm of FSR max
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 100 dB typ, AIN = 1 V
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 ±50 pA/V/°C typ
Normal-Mode Rejection
2
@ 50 Hz, 60 Hz 65 dB min 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
Common-Mode Rejection AIN = 1 V
@ DC 90 dB min 100 dB typ
@ 50 Hz, 60 Hz
2
100 dB min 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
V
DD
+ 30 mV V max
Average Reference Input Current 0.5 μA/V typ
Average Reference Input Current Drift ±0.03 nA/V/°C typ
Normal-Mode Rejection
2
@ 50 Hz, 60 Hz 65 dB min 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
Common-Mode Rejection AIN = 1 V
@ DC 110 dB typ
@ 50 Hz, 60 Hz 110 dB typ 50 Hz ± 1 Hz, 60 Hz ± 1 Hz
1
Temperature range: −40°C to +105°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).