An area-efficient switched-capacitor relaxation oscillator with digitally controlled frequency tunability

This paper describes a programmable low-jitter switched-capacitor (SC) square-wave oscillator for the use in a variety of voice-band signal-processing applications. The core of the circuit is a relaxation oscillator whose oscillation frequency programmability does not resort to variations either in capacitor values or in the sampling frequency. As a result, total capacitance is reduced and, hence, silicon area is minimized while low phase jitter and high resolution programmability are achieved. Simulation results referred to the design of an SC oscillator in 0.35-mu m CMOS technology are presented to demonstrate the feasibility of the proposed approach. Copyright (C) 2008 John Wiley & Sons, Ltd.