Single-supply, second-order, multiple feedback high-pass filter circuit

The multiple-feedback (MFB) high-pass (HP) filter is a 2nd-order active filter. Vref provides a DC offset to accommodate for single-supply applications. This HP filter inverts the signal (Gain = –1 V/V) for frequencies in the pass band. An MFB filter is preferable when the gain is high or when the Q-factor is large (for example, 3 or greater)