Noise and mismatch optimization for capacitive MEMS readout

• 作 者: 张翀 吴其松 尹韬 杨海钢
• 机 构: Institute of Electronics,Chinese Academy of Sciences,Graduate University of the Chinese Academy of S
• 出 处: 半导体学报
• 发表日期: 2009年11期
• 关键词: readout capacitive mismatch capacitance topology capacitor maximize bandwidth am

This paper presents a high precision CMOS readout circuit for a capacitive MEMS gyroscope.A continuous time topology is employed as well as the chopper noise cancelling technique.A detailed analysis of the noise and mismatch of the capacitive readout circuit is given.The analysis and measurement results have shown that thermal noise dominates in the proposed circuit,and several approaches should be used for both noise and mismatch optimization.The circuit chip operates under a single 5V supply,and has a measured capacitance resolution of 0.2 aF/Hz~(1/2).With such a readout circuit,the gyroscope can accurately measure the angular rate with a sensitivity of 15.3 mV/°/s.

This paper presents a high precision CMOS readout circuit for a capacitive MEMS gyroscope. A continuous time topology is employed as well as the chopper noise canceling technique. A detailed analysis of the noise and mismatch of the capacitive readout circuit is given. Analysis and measurement results have shown that thermal noise dominates in the proposed circuit, and several approaches should be used for both noise and mismatch optimization. The circuit chip operates under a single 5V supply, and has a measured capacitance resolution of 0.2 aF / Hz ~ (1 / 2) .With such a readout circuit, the gyroscope can accurately measure the angular rate with a sensitivity of 15.3 mV / ° / s.