Integration and implementation of CMOS-MEMS accelerometer and capacitive sensing circuits

This paper presents a capacitance sensing circuit with low noise and tuned-sensitivity by integrating an in-plane micro-accelerometer. The interface of micro-accelerometer is fully-differential which is capable of reducing common-mode noise and offering higher resolution. Furthermore, this work constructs a noise model to study how to suppress the noise, which influences the sensitive signal effectively. The microstructure and the capacitive sensing circuit were fabricated through the tsmc 0.35 μm mixed-signal 2P4M polycide 3.3/5 V process. As a result, the microstructure with one-axis sensing is successfully integrating with capacitive sensing circuit. Experimental results showed that the whole chip sensitivity measurement is 6.1 mV/g.