A 0.4 \mu \text Bias Instability and 1.2 \mu \text/\surd Hz Noise Floor MEMS Silicon Oscillating Accelerometer With CMOS Readout Circuit

• Published in: IEEE journal of solid-state circuits 2017-02, Vol.52 (2), p.472-482
• Main Authors: Wang, Xi, Zhao, Jian, Zhao, Yang, Xia, Guo Ming, Qiu, An Ping, Su, Yan, Xu, Yong Ping
• Format: Article
• Language: English
• Subjects: Acceleration; Accelerometers; Amplitude control; bias instability; flicker noise; Frequency measurement; inertial navigation; inertial sensor; MEMS oscillating accelerometer; MEMS oscillator; Micromechanical devices; Phase noise; readout circuit; resonant accelerometer; Semiconductor optical amplifiers; time-domain ΣΔ modulator
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2016.2609385

This paper describes a silicon-on-insulator MEMS oscillating accelerometer with a fully differential CMOS continuous-time oscillation sustaining circuit and a digital frequency measurement circuit. To reduce the amplitude-stiffness-induced frequency variation, the effects of flicker noise in the automatic amplitude control circuit are classified into additive and multiplicative components, which are suppressed by chopper stabilization and tail current source free structures, respectively. A low-power digital frequency measurement circuit employing a time-domain ΣA ADC is integrated on chip. The accelerometer achieves a bias instability of 0.4/2 μg, a bias stability of 4.13/13.2 μg, and a noise floor of 1.2/2.6 μg/√Hz, as measured from the analog/digital outputs, respectively, with a scale factor of 280 Hz/g and a full scale of ±20 g. The chip is fabricated in 0.35 μm standard CMOS technology, and consumes 4.37 mW under a 1.5 V supply.