A low-pass continuous-time delta-sigma interface circuit for wideband MEMS gyroscope readout ASIC

This paper presents a low-noise, low-power CMOS interface circuit for MEMS gyroscope readout ASIC. Our interface circuit is composed of a continuous-time delta-sigma modulator, an anti-aliasing filter, and an on-chip reference generator. By using a low-pass delta-sigma modulator instead of a band-pass delta-sigma modulator, a frequency matching circuit is unnecessary which enables wideband operation. A switched-capacitor resistor digital-to-analog converter is exploited to reduce clock jitter sensitivity of the modulator. An anti-aliasing filter rejects the out-band signal, and a low-noise on-chip reference generator is embedded for miniaturization. The proposed circuit is realized in a 0.18 μm CMOS process. It achieves 70.3 dB signal-to-noise ratio in a signal bandwidth from 29.5 kHz to 30.5 kHz with only 0.2 V differential peak-peak input. It dissipates 2.6 mW from a 3.3 V supply.