Datasheet

AD7781
Rev. 0 | Page 10 of 16
OUTPUT NOISE AND RESOLUTION
Table 7 and Table 8 show the rms noise of the AD7781 for the two output data rates and gain settings when using a 3 V and a 5 V reference.
These numbers are typical and are generated with a differential input voltage of 0 V. The peak-to-peak (p-p) resolution is also listed. The
p-p resolution represents the resolution for which there is no code flicker. These numbers are typical.
Table 7. RMS Noise and Peak-to-Peak Resolution When AV
DD
= 3 V and V
REF
= 3 V
Parameter Gain = 128 Gain = 1
Update Rate 10 Hz 16.7 Hz 10 Hz 16.7 Hz
RMS Noise
C Grade 44 nV 65 nV 2.4 V 2.7 V
B Grade 55 nV 90 nV 2.4 V 2.7 V
P-P Resolution
C Grade 17.6 17.1 18.8 18.7
B Grade 17.3 16.6 18.8 18.7
Table 8. RMS Noise and Peak-to-Peak Resolution When AV
DD
= 5 V and V
REF
= 5 V
Parameter Gain = 128 Gain = 1
Update Rate 10 Hz 16.7 Hz 10 Hz 16.7 Hz
RMS Noise
C Grade 49 nV 69 nV 3.0 V 2.7 V
B Grade 60 nV 90 nV 3.0 V 2.7 V
P-P Resolution
C Grade 18.2 17.7 19.3 19.4
B Grade 17.9 17.3 19.3 19.4