A Micropower Front-End for Capacitive Microaccelerometers

This paper presents the measurement results of a micropower differential switched-capacitor front-end designed for capacitive microaccelerometers. Before considering the measurement results, the negative effects of the electrostatic forces are analysed. The designed front-end is capable of reducing these effects. Chopper stabilisation is used to decrease the offset voltage. The front-end was realised with a 0.13 ¿m CMOS process. The silicon area of the front-end is 0.325 mm2. The measurements show that the functionality of the front-end is in line with the theory and it achieves a 53.2 dB maximum SNR with 10 kHz sampling frequency. The worst case current consumption from a 1.8 V supply is 39 ¿A, when four masses are read.