Data Sheet
Parameter
SYSTEM CALIBRATION
Full-Scale Calibration Limit
Zero-Scale Calibration Limit
Input Span
POWER REQUIREMENTS
Power Supply Voltage
AV
DD
– GND
DV
DD
– GND
Power Supply Currents
I
DD
Current
AD7798B/AD7799B
1.05 × FS
−1.05 × FS
0.8 × FS
2.1 × FS
Unit
V max
V min
V min
V max
AD7798/AD7799
Test Conditions/Comments
FS = Full-scale analog input. When V
REF
= AV
DD
, the
differential input must be limited to (0.9 × V
REF
/gain)
if the in-amp is active.
2.7/5.25
2.7/5.25
140
180
400
500
V min/max
V min/max
µA max
µA max
µA max
µA max
µA max
Unbuffered mode, 110 µA typ @ AV
DD
= 3 V,
125 µA typ @ AV
DD
= 5 V
Buffered mode, gain = 1 or 2, 130 µA typ @ AV
DD
= 3 V,
165 µA typ @ AV
DD
= 5 V
AD7798: gain = 4 to 128, 300 µA typ @ AV
DD
= 3 V,
350 µA typ @ AV
DD
= 5 V
AD7799: gain = 4 to 128, 380 µA typ @ AV
DD
= 3 V,
440 µA typ @ AV
DD
= 5 V
I
DD
(Power-Down Mode)
1
1
Temperature range is –40°C to +105°C. At the 19.6 Hz and 39.2 Hz update rates, the INL, power supply rejection (PSR), common-mode rejection (CMR), and normal
mode rejection (NMR) do not meet the data sheet specification if the voltage on the AIN(+) or AIN(−) pins exceeds AV
DD
− 1.6 V typically. When this voltage is
exceeded, the INL, for example, is reduced to 18 ppm of FS typically and the PSR is reduced to 69 dB typically. Therefore, for guaranteed performance at these update
rates, the absolute voltage on the analog input pins needs to be below AV
DD
− 1.6 V.
2
Specification is not production tested, but is supported by characterization data at initial product release.
3
Following a calibration, this error is in the order of the noise for the programmed gain and update rate selected.
4
Recalibration at any temperature removes these errors.
5
Full-scale error applies to both positive and negative full-scale and applies at the factory calibration conditions (AV
DD
= 4 V, gain = 1, T
A
= 25°C).
6
FS[3:0] are the four bits used in the mode register to select the output word rate.
7
Digital inputs equal to DV
DD
or GND.
Rev. B | Page 5 of 28
AD [ ANALOG DEVICES ]
