Datasheet

AD7798/AD7799 Data Sheet
Rev. B | Page 4 of 28
Parameter AD7798B/AD7799B
1
Unit Test Conditions/Comments
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 x 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 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
LOW-SIDE POWER SWITCH
R
ON
7 Ω max AV
DD
= 5 V
9 Ω max AV
DD
= 3 V
Allowable Current
2
30 mA max Continuous current
DIGITAL OUTPUTS (P1 and P2)
Output High Voltage, V
OH
2
AV
DD
− 0.6 V min AV
DD
= 3 V, I
SOURCE
= 100 µA
Output Low Voltage, V
OL
2
0.4
V max
AV
DD
= 3 V, I
SINK
= 100 µA
Output High Voltage, V
OH
2
4 V min AV
DD
= 5 V, I
SOURCE
= 200 µA
Output Low Voltage, V
OL
2
0.4 V max AV
DD
= 5 V, I
SINK
= 800 µA
INTERNAL CLOCK
Frequency
2
64 ± 3% kHz min/max
LOGIC INPUTS
CS
2
Input Low Voltage, V
INL
0.8 V max DV
DD
= 5 V
Input High Voltage, V
INH
0.4
2.0
V max
V min
DV
DD
= 3 V
DV
DD
= 3 V or 5 V
SCLK and DIN
(Schmitt-Triggered Input)
2
V
T
(+) 1.4/2 V min/max DV
DD
= 5 V
V
T
(–) 0.8/1.7 V min/max DV
DD
= 5 V
V
T
(+) – V
T
(–) 0.1/0.17 V min/max DV
DD
= 5 V
V
T
(+) 0.9/2 V min/max DV
DD
= 3 V
V
T
(–) 0.4/1.35 V min/max DV
DD
= 3 V
V
T
(+) − V
T
(–) 0.06/0.13 V min/max DV
DD
= 3 V
Input Currents ±10 µA max V
IN
= DV
DD
or GND
Input Capacitance 10 pF typ All digital inputs
LOGIC OUTPUTS
Output High Voltage, V
OH
2
DV
DD
− 0.6 V min DV
DD
= 3 V, I
SOURCE
= 100 µA
Output Low Voltage, V
OL
2
0.4 V max DV
DD
= 3 V, I
SINK
= 100 µA
Output High Voltage, V
OH
2
4 V min DV
DD
= 5 V, I
SOURCE
= 200 µA
Output Low Voltage, V
OL
2
0.4 V max DV
DD
= 5 V, I
SINK
= 1.6 mA
Floating-State Leakage Current ±10 µA max
Floating-State Output Capacitance 10 pF typ
Data Output Coding
Offset binary