Datasheet
AD7195
Rev. 0 | Page 41 of 44
SUMMARY OF FILTER OPTIONS
The 50 Hz/60 Hz rejection can be improved by setting the
REJ60 bit in the mode register to 1. With FS[9:0] set to 96 and
REJ60 set to 1, the filter response shown in Figure 49 is achieved.
The output data rate is unchanged, but the 50 Hz/60 Hz ± 1 Hz
rejection improves to 73 dB typically.
The AD7195 has several filter options. The filter that is chosen
affects the output data rate, settling time, the rms noise, the stop
band attenuation, and the 50 Hz/60 Hz rejection.
Table 35 shows some sample configurations and the corres-
ponding performance in terms of throughput, settling time and
50 Hz/60 Hz rejection.
–120
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
0 25 50 75 100 125 150
FREQUENCY (Hz)
FILTER GAIN (dB)
08771-059
Figure 49. Sinc
3
Filter Response
(FS[9:0] = 96, Chop Enabled, REJ60 = 1)
Table 35. Filter Summary
1
Filter FS[9:0]
Output Data
Rate (Hz)
Settling
Time (ms) Throughput
2
(Hz) REJ60 50 Hz Rejection (dB)
Sinc
4
, Chop Disabled
3
1 4800 0.83 1200 0 No 50 Hz or 60 Hz rejection
Sinc
4
, Chop Disabled 5 960 4.17 240 0 No 50 Hz or 60 Hz rejection
Sinc
3
, Chop Disabled 5 960 3.125 320 0 No 50 Hz or 60 Hz rejection
Sinc
4
, Chop Disabled 480 10 400 2.5 0 120 dB ( 50 Hz and 60 Hz)
Sinc
3
, Chop Disabled 480 10 300 3.33 0 100 dB (50 Hz and 60 Hz)
Sinc
4
, Chop Disabled 96 50 80 12.5 0 120 dB (50 Hz only)
Sinc
4
, Chop Disabled 96 50 80 12.5 1 82 dB ( 50 Hz and 60 Hz)
Sinc
3
, Chop Disabled 96 50 60 16.7 0 95 dB (50 Hz only)
Sinc
3
, Chop Disabled 96 50 60 16.7 1 67 dB ( 50 Hz and 60 Hz)
Sinc
4
, Chop Disabled 80 60 66.67 15 0 120 dB (60 Hz only)
Sinc
3
, Chop Disabled 80 60 50 20 0 95 dB (60 Hz only)
Sinc
4
, Chop Disabled, Zero
Latency
96 12.5 80 12.5 0
120 dB (50 Hz only)
Sinc
4
, Chop Disabled, Zero
Latency
96 12.5 80 12.5 1
82 dB ( 50 Hz and 60 Hz)
Sinc
4
, Chop Disabled, Zero
Latency
80 15 66.67 15 0
120 dB (60 Hz only)
Sinc
4
, Chop Enabled 96 12.5 160 6.25 1 80 dB (50 Hz and 60 Hz)
Sinc
3
, Chop Enabled 96 16.7 120 8.33 1 67 dB (50 Hz and 60 Hz)
1
These calculations assume a 4.92 MHz stable master clock.
2
Throughput is the rate at which conversions are available when several channels are enabled. In zero latency mode, the output data rate and throughput are equal.
3
For output dates rates greater than 1 kHz, the sinc
4
filter is recommended.