JAJSOX0A March 2024 – June 2024 ADS127L18
ADVANCE INFORMATION
The sinc4 + sinc1 filter is the cascade of a sinc4 and a sinc1 filter section. The fixed OSR = 32 of the sinc4 stage multiplied by the programmable OSR of the sinc1 stage determines the ADC output data rate. The sinc4 + sinc1 filter mode has comparably less latency time than that of the single-stage sinc4 filter. Table 7-7 summarizes the sinc4 + sinc1 filter characteristics.
MODE | fCLK (MHz) |
OSR (A × B)2 |
DATA RATE (kSPS) |
–3dB FREQUENCY (kHz) |
LATENCY TIME (µs)1 |
---|---|---|---|---|---|
Max speed | 32.768 | 64 (32 × 2) |
256 | 87.49 | 10.26 |
High speed | 25.6 | 200 | 68.35 | 13.13 | |
Mid speed | 12.8 | 100 | 34.18 | 26.26 | |
Low speed | 3.2 | 25 | 8.544 | 105.04 | |
Max speed | 32.768 | 128 (32 × 4) |
128 | 52.44 | 14.16 |
High speed | 25.6 | 100 | 40.97 | 18.13 | |
Mid speed | 12.8 | 50 | 20.49 | 36.26 | |
Low speed | 3.2 | 12.5 | 5.121 | 145.04 | |
Max speed | 32.768 | 320 (32 × 10) |
51.2 | 22.36 | 25.88 |
High speed | 25.6 | 40 | 17.47 | 33.13 | |
Mid speed | 12.8 | 20 | 8.735 | 66.26 | |
Low speed | 3.2 | 5 | 2.184 | 265.04 | |
Max speed | 32.768 | 640 (32 × 20) |
25.6 | 11.28 | 45.41 |
High speed | 25.6 | 20 | 8.814 | 58.13 | |
Mid speed | 12.8 | 10 | 4.407 | 116.26 | |
Low speed | 3.2 | 2.5 | 1.102 | 465.04 | |
Max speed | 32.768 | 1280 (32 × 40) |
12.8 | 5.658 | 84.48 |
High speed | 25.6 | 10 | 4.420 | 108.13 | |
Mid speed | 12.8 | 5 | 2.210 | 216.26 | |
Low speed | 3.2 | 1.25 | 0.552 | 865.04 | |
Max speed | 32.768 | 3200 (32 × 100) |
5.12 | 2.266 | 201.66 |
High speed | 25.6 | 4 | 1.770 | 258.13 | |
Mid speed | 12.8 | 2 | 0.885 | 516.26 | |
Low speed | 3.2 | 0.5 | 0.221 | 2065.0 | |
Max speed | 32.768 | 6400 (32 × 200) |
2.56 | 1.133 | 396.98 |
High speed | 25.6 | 2 | 0.885 | 508.13 | |
Mid speed | 12.8 | 1 | 0.443 | 1016.26 | |
Low speed | 3.2 | 0.25 | 0.111 | 4065.04 | |
Max speed | 32.768 | 12800 (32 × 400) |
1.28 | 0.566 | 787.60 |
High speed | 25.6 | 1 | 0.442 | 1008.13 | |
Mid speed | 12.8 | 0.5 | 0.221 | 2016.26 | |
Low speed | 3.2 | 0.125 | 0.055 | 8065.04 | |
Max speed | 32.768 | 32000 (32 × 1000) |
0.512 | 0.226 | 1959.47 |
High speed | 25.6 | 0.4 | 0.177 | 2508.13 | |
Mid speed | 12.8 | 0.2 | 0.089 | 5016.26 | |
Low speed | 3.2 | 0.05 | 0.022 | 20065.04 |
Figure 7-20 illustrates the frequency response of the sinc4 + sinc1 filter for three OSR values. The combined frequency response is the overlay response of the sinc1 filter to the sinc4 filter. For low values of OSR, the response profile is dominated by the rolloff of the sinc4 filter. Nulls in the frequency response occur at n · fDATA, n = 1, 2, 3, and so on. At the null frequencies, the filter has zero gain.