A Silicon Micromechanical Resonator Based CMOS Bandpass Sigma-Delta Modulator

Abstract

This paper describes a bandpass SigmaDelta modulator employing a silicon micromechanical resonator as the loop filter. The micromechanical resonator is chosen primarily for its high quality factor and low power consumption. A 2nd-order prototype bandpass SigmaDelta modulator is realized in a 0.35-mum CMOS process and tested with a 19.6-MHz silicon micromechanical resonator. The measured results show a peak SNDR of 51 dB and a dynamic range of 52.5 dB in a 200-kHz signal bandwidth.