Datasheet

Data Sheet AD7194
Rev. A | Page 15 of 56
RMS NOISE AND RESOLUTION
The following tables show the rms noise, peak-to-peak noise,
effective resolution, and noise-free (peak-to-peak) resolution of
the AD7194 for various output data rates and gain settings with
chop disabled for the sinc
4
and sinc
3
filters and for fast settling
mode. The numbers given are for the bipolar input range with
an 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. It is important
to note that the effective resolution is calculated using the rms
noise, whereas the peak-to-peak resolution is calculated based
on peak-to-peak noise. The peak-to-peak resolution represents
the resolution for which there is no code flicker. With chop
enabled, the resolution improves by 0.5 bits.
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 8 16 32 64 128
1023 4.7 852.5 370 57 35 18 13 11
640 7.5 533 440 73 41 24 17 13
480 10 400 470 83 45 28 18 16
96 50 80 1100 150 85 52 38 34
80 60 66.7 1200 170 94 56 42 38
32
150
26.7
1800
260
150
86
65
59
16 300 13.3 2500 360 210 130 95 83
5 960 4.17 4500 640 370 230 170 150
2 2400 1.67 7500 1100 600 380 280 240
1 4800 0.83 26,000 3400 1800 940 550 390
Table 7. Peak-to-Peak Noise (nV) vs. Gain and Output Data Rate
Filter Word
(Decimal)
Output Data
Rate (Hz)
Settling
Time (ms)
Gain of
1 8 16 32 64 128
1023 4.7 852.5 2200 340 200 120 84 70
640 7.5 533 2700 430 260 150 100 85
480 10 400 3000 480 300 170 120 100
96 50 80 6600 950 540 350 250 210
80 60 66.7 7200 1000 610 370 270 220
32 150 26.7 11,000 1600 970 580 430 370
16 300 13.3 17,000 2400 1400 840 620 530
5
960
4.17
35,000
4800
2500
1500
1100
1000
2 2400 1.67 56,000 7500 4200 2900 1800 1700
1 4800 0.83 175,000 23,000 12,000 7100 3600 2600
Table 8. 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 8 16 32 64 128
1023 4.7 852.5 24 (22.1) 24 (21.8) 24 (21.6) 24 (21.3) 23.5 (20.8) 22.8 (20.1)
640 7.5 533 24 (21.8) 24 (21.5) 23.9 (21.2) 23.6 (21) 23.1 (20.6) 22.5 (19.8)
480 10 400 24 (21.7) 24 (21.3) 23.7 (21) 23.4 (20.8) 23 (20.3) 22.2 (19.6)
96 50 80 23.1 (20.5) 23 (20.3) 22.8 (20.1) 22.5 (19.8) 22 (19.3) 21.1 (18.5)
80 60 66.7 23 (20.4) 22.9 (20.3) 22.7 (20) 22.4 (19.7) 21.8 (19.1) 21 (18.4)
32 150 26.7 22.4 (19.8) 22.3 (19.6) 22 (19.3) 21.8 (19) 21.2 (18.5) 20.3 (17.7)
16 300 13.3 21.9 (19.2) 21.8 (19) 21.5 (18.8) 21.2 (18.5) 20.7 (17.9) 19.8 (17.2)
5 960 4.17 21.1 (18.4) 21 (18) 20.7 (17.9) 20.4 (17.7) 19.8 (17.1) 19 (16.3)
2 2400 1.67 20.4 (17.6) 20.3 (17.3) 20 (17.2) 19.6 (16.7) 19.1 (16.4) 18.3 (15.5)
1
4800
0.83
18.6 (15.8)
18.5 (15.7)
18.4 (15.7)
18.3 (15.4)
18.1 (15.4)
17.6 (14.9)
1
The output peak-to-peak (p-p) resolution is listed in parentheses.