A Micropower Front End for Three-Axis Capacitive Microaccelerometers

This paper presents the measurement results of a micropower switched-capacitor front end that was designed for three-axis capacitive microaccelerometers. The designed front end can reduce the distorting effects of the electrostatic forces and can be used in single-ended and differential modes. The front end was realized with a 0.13-mum bipolar complimentary metal-oxide-semiconductor process. The silicon area of the front end is 0.30 mm². The measurements show that the functionality of the front end follows the theory in both modes. Consuming 20 muA from a 1.8-V supply, it achieves noise densities of 424, 607, and 590 mug/radic(Hz) in the x-, y-, and z-directions, respectively, when each mass is sampled at 1 kHz in the differential mode.