SPRUJF2A March 2026 – March 2026 AM13E23019
The PGA output can be routed to a pin through an embedded series resistor for the purpose of low-pass filtering the amplified signal. The filter resistance is software selectable using the PGACTL[FILT_RES_SEL] register field. The default selection of PGACTL[FILT_RES_SEL] = 0 disables the filter path.
The cutoff frequency can be estimated using the standard low-pass RC given by:
Each gain mode requires a minimum amount of series resistance when filtering is enabled. The values are shown in Table 17-6. Also, the external capacitor value CFILTER influences the ADC sampling performance. See Section 17.10.2.2 for more information.
| PGACTL[GAIN] | Minimum RFILT Required PGACTL[FILT_RES_SEL] |
|---|---|
| 0 | 50Ω |
| 1 | 50Ω |
| 2 | 50Ω |
| 3 | 100Ω |
| 4 | 100Ω |
| 5 | 200Ω |
| 6 | 400Ω |