Title :
Precision readout circuits for capacitive microaccelerometers
Author :
Yazdi, Navid ; Kulah, Haluk ; Najafi, Khalil
Author_Institution :
Center of Wireless Integrated Microsystems, Michigan Univ., Ann Arbor, MI, USA
Abstract :
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. The first generation of the circuit resolves 75 aF of capacitance on ∼120 pF parasitic capacitance with a 200 kHz sampling rate, and the second generation resolves 20 aF with 1 MHz sampling rate. The overall sensor-circuit module has a noise floor of 1.6 μg/√Hz at ambient atmosphere.
Keywords :
accelerometers; capacitive sensors; microsensors; modules; readout electronics; switched capacitor networks; 1 MHz; 120 pF; 20 aF; 200 kHz; 75 aF; AC-bridge; MEMS accelerometer; accelerometer hybrid-integration; capacitive microaccelerometers; capacitive microsensor interfaces; capacitive readout front-end circuits; high DC stability; high-precision accelerometers; micromachined micro-g accelerometer; noise floor; parasitic capacitance; precision readout circuits; resolution based trade-offs; sampling rate; sensor-circuit module; switched-capacitor circuit; Accelerometers; Capacitive sensors; Capacitors; Circuits; Microsensors; Packaging; Parasitic capacitance; Pulse amplifiers; Sampling methods; Voltage;
Conference_Titel :
Sensors, 2004. Proceedings of IEEE
Print_ISBN :
0-7803-8692-2
DOI :
10.1109/ICSENS.2004.1426091
