Performance limits of a closed-loop, micro-g silicon accelerometer with deposited rigid electrodes

Silicon micro-g accelerometers are of increasing demand for the new generation of lightweight low cost inertial measurement units (IMUs) and microgravity measurement systems. This paper presents modeling and noise analysis of a closed-loop micro-g accelerometer with deposited sense and feedback electrodes, and direct digital output. Modeling and noise analysis have been essential to identifying the performance limits in addition to design and development of the accelerometer. The paper first briefly reviews the sensor and its interface electronics, followed by the complete time domain modeling and simulation of the closed-loop electromechanical accelerometer. The simulation results show achievement of less than 10 μg direct digital output in a ±1 g range, which is equivalent to 17.6 bits dynamic range. Also, the mechanical and electrical noise analysis indicate a noise floor of 0.72 μg/√Hz without vacuum packaging