SLAU847D October 2022 – May 2024 MSPM0L1105 , MSPM0L1106 , MSPM0L1227 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1 , MSPM0L1343 , MSPM0L1344 , MSPM0L1345 , MSPM0L1346 , MSPM0L2227 , MSPM0L2228 , MSPM0L2228-Q1
The OPA peripheral implements chopper stabilization to reduce offset, drift, and 1/f noise. CFG.CHOP can be set to 0x1 for standard chopping mode which requires an external filter. Note that the OPA automatically scales the chopping frequency based on CFG.GAIN which is used to select the OPA PGA gain but is also needed with external filter when the standard chopping is used as shown in Table 17-19.
GAIN | Inverting / Non-inverting Gain | Chopping Frequency (Hz) | Resistor(kΩ) | Capacitor(nF) |
---|---|---|---|---|
0x0 | 1x | 125k | 1 | 10 |
0x1 | -1x / 2x | 62.5k | 1 | 30 |
0x2 | -3x / 4x | 31.25k | 1 | 90 |
0x3 | -7x / 8x | 15.6k | 1 | 270 |
0x4 | -15x / 16x | 7.8k | 1 | 810 |
0x5 | -31x / 32x | 3.9k | 1 | 2400 |