A 10 NANO-G/RT-HZ RESONANT MEMS ACCELEROMETER EMPLOYING ANTI-ALIASING CONTROL

Abstract

Optimization of the oscillator front-end for resonant sensors is critical to addressing key metrics such as noise floor and output stability. This paper reports a method to improve the noise floor of resonant MEMS accelerometers by avoiding aliasing of high-frequency seismic noise for long-period measurements. In particular, the optimization of a Phase Locked Loop (PLL) front-end is employed for continuous tracking of the output. A noise floor improvement of 13x is seen in comparison to the case with no anti-aliasing control. A custom PLL is designed to mitigate the impact of high-frequency noise enabling the realization of a resonant accelerometer sensor module with a noise floor of 10 ng/√Hz.