SBAS970 October 2019 ADS1235-Q1
PRODUCTION DATA.
To reduce 50-Hz and 60-Hz noise interference, configure the data rate and filter to reject noise at 50 Hz and 60 Hz. Table 5 summarizes the 50-Hz and 60-Hz noise rejection versus data rate and filter mode. The table values are based on 2% and 6% tolerance of signal frequency to ADC clock frequency. For the sinc filter, increase noise rejection by increasing the order of the filter. Common-mode noise is also rejected at these frequencies.
| DATA RATE (SPS) | FILTER TYPE | DIGITAL FILTER RESPONSE (dB) | |||
|---|---|---|---|---|---|
| 50 Hz ±2% | 60 Hz ±2% | 50 Hz ±6% | 60 Hz ±6% | ||
| 2.5 | FIR | –113 | –99 | –88 | –80 |
| 2.5 | Sinc1 | –36 | –37 | –40 | –37 |
| 2.5 | Sinc2 | –72 | –74 | –80 | –74 |
| 2.5 | Sinc3 | –108 | –111 | –120 | –111 |
| 2.5 | Sinc4 | –144 | –148 | –160 | –148 |
| 5 | FIR | –111 | –95 | –77 | –76 |
| 5 | Sinc1 | –34 | –34 | –30 | –30 |
| 5 | Sinc2 | –68 | –68 | –60 | –60 |
| 5 | Sinc3 | –102 | –102 | –90 | –90 |
| 5 | Sinc4 | –136 | –136 | –120 | –120 |
| 10 | FIR | –111 | –94 | –73 | –68 |
| 10 | Sinc1 | –34 | –34 | –25 | –25 |
| 10 | Sinc2 | –68 | –68 | –50 | –50 |
| 10 | Sinc3 | –102 | –102 | –75 | –75 |
| 10 | Sinc4 | –136 | –136 | –100 | –100 |
| 16.6 | Sinc1 | –34 | –21 | –24 | –21 |
| 16.6 | Sinc2 | –68 | –42 | –48 | –42 |
| 16.6 | Sinc3 | –102 | –63 | –72 | –63 |
| 16.6 | Sinc4 | –136 | –84 | –96 | –84 |
| 20 | FIR | –95 | –94 | –66 | –66 |
| 20 | Sinc1 | –18 | –34 | –18 | –24 |
| 20 | Sinc2 | –36 | –68 | –36 | –48 |
| 20 | Sinc3 | –54 | –102 | –54 | –72 |
| 20 | Sinc4 | –72 | –136 | –72 | –96 |
| 50 | Sinc1 | –34 | –15 | –24 | –15 |
| 50 | Sinc2 | –68 | –30 | –48 | –30 |
| 50 | Sinc3 | –102 | –45 | –72 | –45 |
| 50 | Sinc4 | –136 | –60 | –96 | –60 |
| 60 | Sinc1 | –13 | –34 | –12 | –24 |
| 60 | Sinc2 | –27 | –68 | –24 | –48 |
| 60 | Sinc3 | –40 | –102 | –36 | –72 |
| 60 | Sinc4 | –53 | –136 | –48 | –96 |