A high precision time-multiplexed fully differential interface ASIC for capacitive MEMS accelerometer

Abstract

A high precision time-multiplexed fully differential interface Application specific integrated circuit (ASIC) for micromechanical capacitive accelerometer is presented in this paper. A time-multiplexed fully differential capacitor-to-voltage (C-V) converter employs the half-bridge sensing structure and two paralleled single-end charge integrators to substitute the full-bridge or fully differential sensing element and restrain the influence of the common-mode voltage. A time-multiplexed fully differential switch-capacitor (SC) programmable gain amplifier (PGA) with continuous output is proposed, providing continuous signals to the following circuits. The proposed interface is fabricated in a 0.18 [Formula: see text]m CMOS process, occupying an area of [Formula: see text]. The measured results indicate that the total power dissipation is 8.25 mW from a 3.3 V power supply. The noise floor of the accelerometer is 10.5 [Formula: see text]g/Hz1/2, and the achieved figure of merit (FOM, 5.5 pW/Hz) is better than the previously reported works.