ABSTRACT
This chapter presents a phase locked loop (PLL)-based readout circuit architecture for a micro-electromechanical system (MEMS) silicon oscillating accelerometer (SOA). It describes the design of the PLL-based readout circuit and presents a prototype high-performance MEMS oscillating accelerometer with the readout circuit implemented in CMOS technology. The chapter discusses a MEMS SOA with a PLL-based readout circuit, aiming to improve the bias-instability. The phase detectors can be divided into two categories, namely, the discrete time PD and continuous time PD. Discrete PD is usually edge-triggered, such as XOR PD and tri-state phase frequency detector. Since the output signal from the MEMS oscillator is sinusoidal, a waveform shaping circuit is required. In AAC-based MEMS SOA readout circuit, the front-end amplifier not only needs to amplify the transducer signal, but also to provide correct phase shift to satisfy the oscillation condition. In the PLL-based MEMS SOA, the PLL can conveniently provide additional phase shift to satisfy the oscillation condition.
