The Butterworth Sallen-Key (SK) high-pass (HP) filter is a 2nd-order active filter. Vref provides a DC offset to accommodate for single-supply applications. An SK filter is usually preferred when small Q factor is desired, noise rejection is prioritized and when a non-inverting gain of the filter stage is required. The Butterworth topology provides a maximally flat gain in the pass band.
- Input: Vi = -2.45 V to 2.45 V
- Output: Vo = 0.05 V to 4.95 V
- Gain: 1 V/V
- Cutoff frequency: 1 kHz
- Max frequency: 10 kHz
- Vref = 2.5 V