Reduction of Operational Amplifiers Finite Gain Effects in Switched-Capacitor Biquads

Abstract

A combined approach for reducing the errors in the pole frequency f_p , the pole Q - factor Q_p and the magnitude at the pole frequency H_p , of switched capacitor biquads is presented. First, the conventional integrators in the biquads are replaced with gain-and offset-compensated integrators. Next, the errors ∆f_p / f_p, ∆Q_p / Q and ∆H_p / H are minimized by modifying three capacitances: two feedback capacitances and feed forward capacitance. The effectiveness of this approach is demonstrated by designing a bandpass biquad.