Double-Capacitor Technique for Wide Frequency Range Phase Compensation in G_m-C and MOSFET-C Filters

Abstract

A double-capacitor phase error compensation configuration is proposed for G_m-C and MOSFET-C filters. The use of two capacitors enables the effective compensation capacitance to track with the tuning resistance, thereby making it more effective over a wider frequency tuning range as compared to the conventional single-capacitor configuration. Simulations of 5th-order Chebyshev filters in a 0.18µm CMOS process with more than one octave tuning range were carried out to demonstrate the viability of the proposed double-capacitor configuration for both G_m-C and MOSFET-C filters.