Abstract
This study presents a capacitance sensing circuit with high sensitivity and linearity, by integrating a vertical microaccelerometer. The proposed capacitive sensing circuit is composed of a capacitance-voltage converter to amplify the readout signals, and a differential circuit, which is capable of reducing common-mode noise and offering high resolution. The microstructure and the capacitive sensing circuit were fabricated through TSMC 0.35 μm mixed-signal 2P4M polycide 3.3/5 V process. Experimental results demonstrated that the sensing circuit exhibited a linear capacitance-to-voltage relation. The sensitivity and resolution of differential sensing circuit are 21.32 mV/fF/V and 0.28 aF/√Hz, respectively. Moreover, the microstructure is successfully integrating with capacitive sensing circuit, in which with high resolution and linearity. The sensitivity and nonlinearity of the accelerometer are 9.8 mV/g/V and 4.7 ％, respectively.