A High-Performance Self-clocked Digital-Output Quartz Gyroscope

Abstract

High-performance electro-static gyroscopes require expensive vacuum-packaging, to maintain the high-Q of the MEMS, and may require high actuation voltages. Piezo sensors, on the other hand, do not suffer from these shortcomings. In this work, the architecture and the measurements results of a high-performance quartz gyro are presented. The architecture of the gyroscope interface ASIC adopts a mostly-digital implementation, where the drive-loop processing, demodulation, and post-filtering are implemented in the digital domain. Furthermore, the ASIC clock is based on self-clocking scheme, where the gyro drive frequency drives all internal clocks. The digital implementation, combined with self-clocking, allows the read-out ASIC to interface to different quartz-gyro sensing elements, with a wide range of drivefrequencies. The ASIC is tested with a tuning fork quartz gyro sensing element. The complete gyro sensor module achieves a ±500 deg/s input range, and a noise-floor of 2.5 mdeg/s/√Hz.