Analog VLSI Circuits for Inertial Sensory Systems

Vibration sensors are needed in a variety of applications, such as geophysical sensing, machinery vibration and failure prediction, tracking of vehicles, underwater pressure gradient detection, microphones, and in robotic applications. Low noise electronics is critical for creating a highsensitivity vibration sensor, especially in low proof mass MEMS designs. We have designed, fabricated, and tested an ultra low noise analog VLSI circuit with feedback adaptation for use as the electronic portion of a MEMS vibration sensor. The electronics performs novel multiplicative feedback offset compensation to improve the performance of demodulator building blocks used in traditional low noise sensing electronics. The design is robust to parasitics and flicker noise. Experimental noise measurements show that the sensing electronics is capable of detecting 2.5x1iangstrom of displacement, about one order of magnitude more sensitive than electronics in state-of-the-art commercial sensors. Thesis Supervisor: Rahul Sarpeshkar Title: Assistant Professor of Electrical Engineering