Low-noise CMOS integrated sensing electronics for capacitive MEMS strain sensors

This paper describes a high-performance strain sensing microsystem. A MEMS capacitive strain sensor converts an input strain to a capacitance change with a sensitivity of 26.5 aF per 0.1 /spl mu//spl epsiv/. Low-noise integrated sensing electronics, employing a continuous time synchronous detection architecture, convert the capacitive signal to an output voltage for further signal processing. The prototype microsystem achieves a minimum detectable strain of 0.09 /spl mu//spl epsiv/ over a 10 kHz bandwidth with a dynamic range of 81 dB. The sensing electronics consume 1.5 mA from a 3 V supply.