Datasheet

AD7192
Rev. A | Page 14 of 40
RMS NOISE AND RESOLUTION
The AD7192 has a choice of two filter types: sinc
4
and sinc
3
.
In addition, the AD7192 can be operated with chop enabled
or chop disabled.
The following tables show the rms noise of the AD7192 for some
of the output data rates and gain settings with chop disabled
and enabled for the sinc
4
and sinc
3
filters. The numbers given
are for the bipolar input range with the external 5 V reference.
These numbers are typical and are generated with a differential
input voltage of 0 V when the ADC is continuously converting
on a single channel. The effective resolution is also shown, and
the output peak-to-peak (p-p) resolution, or noise-free resolution,
is listed in parentheses. It is important to note that the effective
resolution is calculated using the rms noise, whereas the p-p
resolution is calculated based on peak-to-peak noise. The p-p
resolution represents the resolution for which there is no code
flicker. These numbers are typical and are rounded to the
nearest ½ LSB.
SINC
4
CHOP DISABLED
Table 6. RMS Noise (nV) vs. Gain and Output Data Rate
Filter Word
(Decimal)
Output
Data Rate
(Hz)
Settling
Time
(ms) Gain of 1 Gain of 8 Gain of 16 Gain of 32 Gain of 64 Gain of 128
1023 4.7 852.5 350 50 30 18 13 11
640 7.5 533 425 62 36 21 15 13
480 10 400 490 85 43 23 17 15
96 50 80 2000 260 134 73 46 34
80 60 66.7 2100 273 139 77 48 38
40 120 33.3 2400 315 175 95 64 51
32 150 26.7 2500 335 185 110 71 58
16 300 13.3 3100 420 240 145 95 81
5 960 4.17 4800 690 390 240 170 145
2 2400 1.67 7500 1100 640 390 273 235
1 4800 0.83 16,300 2200 1200 670 427 345
Table 7. Effective Resolution (Peak-to-Peak Resolution) vs. Gain and Output Data Rate
Filter Word
(Decimal)
Output
Data Rate
(Hz)
Settling
Time
(ms) Gain of 1
1
Gain of 8
1
Gain of 16
1
Gain of 32
1
Gain of 64
1
Gain of 128
1
1023 4.7 852.5 24 (22) 24 (22) 24 (21.5) 24 (21.5) 23.5 (21) 22.5 (20)
640 7.5 533 24 (22) 24 (21.5) 24 (21.5) 23.5 (21) 23 (20.5) 22.5 (20)
480 10 400 24 (21.5) 23.5 (21) 23.5 (21) 23.5 (21) 23 (20.5) 22 (19.5)
96 50 80 22 (19.5) 22 (19.5) 22 (19.5) 22 (19.5) 21.5 (19) 21 (18.5)
80 60 66.7 22 (19.5) 22 (19.5) 22 (19.5) 21.5 (19) 21.5 (19) 20.5 (18)
40 120 33.3 22 (19.5) 21.5 (19) 21.5 (19) 21.5 (19) 21 (18.5) 20.5 (18)
32 150 26.7 21.5 (19) 21.5 (19) 21.5 (19) 21 (18.5) 21 (18.5) 20 (17.5)
16 300 13.3 21.5 (19) 21.5 (19) 21 (18.5) 21 (18.5) 20.5 (18) 19.5 (17)
5 960 4.17 20.5 (18) 20.5 (18) 20.5 (18) 20 (17.5) 19.5 (17) 19 (16.5)
2 2400 1.67 20 (17.5) 20 (17.5) 19.5 (17) 19.5 (17) 19 (16.5) 18 (15.5)
1 4800 0.83 19 (16.5) 19 (16.5) 19 (16.5) 18.5 (16) 18.5 (16) 17.5 (15)
1
The output peak-to-peak (p-p) resolution is listed in parentheses.