3rd-Order Multiple-Feedback High-Pass Filter

Cascade: a 1st-order RC stage (R3, C4) feeds the 2nd-order multiple-feedback high-pass stage shown above. Inverting.

Design from specification

3rd-order all-pole filter as a 1st-order RC stage + a 2nd-order MFB stage. Pick an approximation and cutoff; all seven R/C values are computed and rounded to the chosen E-series.

Approximation: Cutoff f_c [Hz]: C [F] (optional): R series: C series:

Components (analyse / override)

R1 [Ω]: R2 [Ω]: C1 [F]: C2 [F]: C3 [F]: R3 [Ω] (RC): C4 [F] (RC):

Results

Components: R1 = — R2 = — C1 = — C2 = — C3 = — R3 = — C4 = —

2nd-order section: f₀ = — Hz Q = — ζ = — HF gain = —

Transfer function:
H(s) = —

Equivalent block diagram

—

Poles

—

Phase margin

—

Oscillation (ringing) frequency

—

Overshoot of the step response

—

Final value of the step response

—