Precision readout circuits for capacitive microaccelerometers

2004-01-01
Yazdi, N
Külah, Haluk
Najafi, K
This paper presents a review of capacitive readout front-end circuits for high-precision accelerometers. The primary design parameters and the trade-offs affecting the resolution are presented. The discussions apply to all capacitive microsensor interfaces. Also a high-sensitivity capacitive accelerometer interface circuit for hybrid-integration with a surface/bulk micromachined micro-g accelerometer is described [7, 10]. The first generation of the circuit resolves 75aF of capacitance on similar to 120pF parasitic capacitance with a 200kHz sampling rate, and the second generation resolves 20aF with 1MHz sampling rate. The overall sensor-circuit module has a noise floor of 1.6 mu g/root HZ at ambient atmosphere.