Design of an Energy-Efficient Interface Circuit for a MEMS-based Capacitive Pressure Sensor

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This thesis presents an incremental ?? capacitance-to-digital converter (CDC) that serves as an interface circuit for a MEMS-based pressure sensor. The thesis presents a systematic analysis of the CDC and compares different CDC architectures. A novel non-linear CDC is also proposed and analysed. Energy-efficiency of the CDC is improved by implementation of various design techniques like double sampling, system-level chopping and a novel inverter-based OTA. The CDC has been designed in such a way that it can operate with either an on-chip or external pressure sensor. The CDC can be tuned to compensate for a wide range of baseline capacitance. The CDC operates over a pressure range of 0-1.3 bar and achieves a pressure resolution of 1e?5 bar (equivalent to a resolution of 16 bits). The CDC is implemented in NXP 0.16?m 1P6M technology. The circuit design and layout of the CDC are presented. The CDC consumes 2.33?A from a 1.2V supply resulting in an energy consumption of only 2.01nJ, a significant improvement over the state-of-the-art.