SBASAE7 August 2022 ADS131M02-Q1
PRODUCTION DATA
The ADS131M02-Q1 includes an optional high-pass filter to eliminate any systematic offset or low-frequency noise. The filter is enabled by writing any value in the DCBLOCK[3:0] bits in the CD_TH_LSB register besides 0h. The DC block filter can be enabled and disabled on a channel-by-channel basis by the DCBLKn_DIS bit in the CHn_CFG register for each respective channel.
Figure 8-8 shows the topology of the DC block filter. Coefficient a represents a register configurable value that configures the cutoff frequency of the filter. The cutoff frequency is configured using the DCBLOCK[3:0] bits in the CD_TH_LSB register. Table 8-4 describes the characteristics of the filter for various DCBLOCK[3:0] settings. The data provided in Table 8-4 is provided for an 8.192-MHz CLKIN frequency and a 4-kSPS data rate. The frequency response of the filter response scales directly with the frequency of CLKIN and the data rate.
DCBLOCK[3:0] | a COEFFICIENT | –3-dB CORNER(1) | PASS-BAND ATTENUATION(1) | SETTLING TIME (Samples) | ||
---|---|---|---|---|---|---|
50 Hz | 60 Hz | SETTLED >99% | FULLY SETTLED | |||
0h | DC block filter disabled | |||||
1h | 1/4 | 181 Hz | 11.5 dB | 10.1 dB | 17 | 88 |
2h | 1/8 | 84.8 Hz | 5.89 dB | 4.77 dB | 36 | 187 |
3h | 1/16 | 41.1 Hz | 2.24 dB | 1.67 dB | 72 | 387 |
4h | 1/32 | 20.2 Hz | 657 mdB | 466 mdB | 146 | 786 |
5h | 1/64 | 10.0 Hz | 171 mdB | 119 mdB | 293 | 1585 |
6h | 1/128 | 4.99 Hz | 43.1 mdB | 29.9 mdB | 588 | 3182 |
7h | 1/256 | 2.49 Hz | 10.8 mdB | 7.47 mdB | 1178 | 6376 |
8h | 1/512 | 1.24 Hz | 2.69 mdB | 1.87 mdB | 2357 | 12764 |
9h | 1/1024 | 622 mHz | 671 µdB | 466 µdB | 4714 | 25540 |
Ah | 1/2048 | 311 mHz | 168 µdB | 116 µdB | 9430 | 51093 |
Bh | 1/4096 | 155 mHz | 41.9 µdB | 29.1 µdB | 18861 | 102202 |
Ch | 1/8192 | 77.7 mHz | 10.5 µdB | 7.27 µdB | 37724 | 204447 |
Dh | 1/16384 | 38.9 mHz | 2.63 µdB | 1.82 µdB | 75450 | 409156 |
Eh | 1/32768 | 19.4 mHz | 655 ndB | 455 ndB | 150901 | 820188 |
Fh | 1/65536 | 9.70 mHz | 164 ndB | 114 ndB | 301803 | 1627730 |