AD7195 Analog Devices, AD7195 Datasheet - Page 41

• Manufacturer Part Number: AD7195
• Description: 4.8 kHz, Ultralow Noise, 24-Bit Sigma-Delta ADC with PGA and AC Excitation
• Manufacturer: Analog Devices

Specifications of AD7195

• Resolution (bits): 24bit
• # Chan: 4
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni,SE-Bip,SE-Uni
• Ain Range: (2Vref/PGA Gain) p-p
• Adc Architecture: Sigma-Delta
• Pkg Type: CSP

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.
Table 35. Filter Summary
Filter
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
Sinc
1
2
3
These calculations assume a 4.92 MHz stable master clock.
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.
For output dates rates greater than 1 kHz, the sinc
Latency
Latency
Latency
4
4
3
4
3
4
4
3
3
4
3
4
4
4
4
3
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled
, Chop Disabled, Zero
, Chop Disabled, Zero
, Chop Disabled, Zero
, Chop Enabled
, Chop Enabled
–100
–110
–120
–10
–20
–30
–40
–50
–60
–70
–80
–90
0
0
(FS[9:0] = 96, Chop Enabled, REJ60 = 1)
25
Figure 49. Sinc
3
50
FREQUENCY (Hz)
1
FS[9:0]
1
5
5
480
480
96
96
96
96
80
80
96
96
80
96
96
3
Filter Response
75
100
Output Data
Rate (Hz)
4800
960
960
10
10
50
50
50
50
60
60
12.5
12.5
15
12.5
16.7
4
filter is recommended.
125
150
Settling
Time (ms)
0.83
4.17
3.125
400
300
80
80
60
60
66.67
50
80
80
66.67
160
120
Rev. 0 | Page 41 of 44
SUMMARY OF FILTER OPTIONS
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.
Throughput
1200
240
320
2.5
3.33
12.5
12.5
16.7
16.7
15
20
12.5
12.5
15
6.25
8.33
2
(Hz)
REJ60
0
0
0
0
0
0
1
0
1
0
0
0
1
0
1
1
50 Hz Rejection (dB)
No 50 Hz or 60 Hz rejection
120 dB ( 50 Hz and 60 Hz)
100 dB (50 Hz and 60 Hz)
82 dB ( 50 Hz and 60 Hz)
95 dB (50 Hz only)
67 dB ( 50 Hz and 60 Hz)
95 dB (60 Hz only)
82 dB ( 50 Hz and 60 Hz)
No 50 Hz or 60 Hz rejection
No 50 Hz or 60 Hz rejection
120 dB (50 Hz only)
120 dB (60 Hz only)
120 dB (50 Hz only)
120 dB (60 Hz only)
80 dB (50 Hz and 60 Hz)
67 dB (50 Hz and 60 Hz)
AD7195