An Interface ASIC for MEMS Vibratory Gyroscopes With a Power of 1.6 mW, 92 dB DR and 0.007°/s/<inline-formula> <tex-math notation="LaTeX">$\sqrt {\rm {Hz}} $ </tex-math> </inline-formula> Noise Floor Over a 40 Hz Band

Abstract

This paper reports on the implementation of an interface ASIC for MEMS vibratory gyroscopes exhibiting a wide tuning range from 7 to 31 kHz with a power consumption of 1.6 mW and a dynamic range of 92 dB over a signal band of 40 Hz. The drive loop of the system employs a high voltage stage based on flying capacitors for the excitation of the drive mass allowing a startup time of 44 ms. For the detection of the Coriolis signal, a fourth-order closed-loop electromechanical sense loop deploying continuous-time (CT) circuit techniques and ΔΣ-modulation is implemented. The sense loop deploys a high-Q electronic resonator based on gm-C circuits and a collocated charge-integrator for signal readout and for generating feedback forces. The readout interface with an active circuit area of 2.42 mm2 is fabricated in a 0.35 μm CMOS technology with a HV-module. The ASIC achieves a noise floor of 0.007°/s/√Hz over 40 Hz while the full-scale range is higher than ±1400°/s and the bias stability measures 2.6°/h. The wide tuning capability of the ASIC is demonstrated on the basis of two tested MEMS gyroscopes for different applications with an equal ASIC performance.