Datasheet

Data Sheet AD7190
Rev. C | Page 15 of 40
RMS NOISE AND RESOLUTION
The AD7190 has a choice of two filter types: sinc
4
and sinc
3
.
In addition, the AD7190 can be operated with chop enabled
or chop disabled.
The following tables show the rms noise of the AD7190 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 resol-
ution, is listed in parentheses. It is important to note that the
effective resolution is calculated using the rms noise, wheras 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 4.7 852.5 250 38 21 12 10 8.5
640 7.5 533 310 45 25 16 12 10.5
480 10 400 330 50 30 18 14 11.5
96 50 80 900 125 78 45 33 28
80 60 66.7 970 140 88 52 36 31
32 150 26.7 1460 215 125 75 55 48
16
300
13.3
1900
285
170
100
75
67
5 960 4.17 3000 480 280 175 140 121
2 2400 1.67 5000 780 440 280 220 198
1 4800 0.83 14,300 1920 1000 550 380 295
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 (22.5) 24 (22) 24 (22) 24 (22) 24 (21) 23 (20.5)
640 7.5 533 24 (22) 24 (22) 24 (22) 24 (21.5) 23.5 (21) 23 (20)
480
10
400
24 (22)
24 (22)
24 (21.5)
24 (21.5)
23.5 (20.5)
22.5 (20)
96 50 80 23.5 (20.5) 23.5 (20.5) 23 (20) 22.5 (20) 22 (19.5) 21.5 (18.5)
80 60 66.7 23.5 (20.5) 23 (20.5) 22.5 (20) 22.5 (20) 22 (19.5) 21.5 (18.5)
32 150 26.7 22.5 (20) 22.5 (19.5) 22.5 (19.5) 22 (19.5) 21.5 (18.5) 20.5 (18)
16 300 13.3 22.5 (19.5) 22 (19.5) 22 (19) 21.5 (19) 21 (18.5) 20 (17.5)
5 960 4.17 21.5 (19) 21.5 (18.5) 21 (18.5) 21 (18) 20 (17.5) 19.5 (16.5)
2 2400 1.67 21 (18) 20.5 (18) 20.5 (17.5) 20 (17.5) 19.5 (16.5) 18.5 (16)
1 4800 0.83 19.5 (16.5) 19.5 (16.5) 19.5 (16.5) 19 (16.5) 18.5 (16) 18 (15.5)
1
The output peak-to-peak (p-p) resolution is listed in parentheses.