Interface IC Design for MEMS Resonant Devices

This book provides an overview of different circuits and systems that can be interfaced with a MEMS resonant micro-gyroscope. Techniques for measuring the rotation rate of the gyroscope based on either amplitude- or phase-shift modulation of its output signal are introduced, along with challenges associated with optimizing the noise performance to achieve navigation-grade levels of sensitivity as the frequency is scaled into the MHz regime. Mathematical models are derived to describe the operation of the sensor and used to generate equivalent electrical circuit models of the gyroscope. An IC design strategy is then outlined and implemented to optimize the drive loop and sense channel for power and noise, and steps toward reducing this noise as the system is pushed to navigation-grade performance are presented that maintain optimum system power consumption. DC charge pump design is also examined, and strategies that can be used to generate larger polarization voltages on the ASIC are presented. The material discussed in this book can also be applied to other resonant devices, such as low-frequency gyroscopes and RF resonators.