Technology-portable mixed-signal sensing architecture for CMOS-integrated z-axis surface-micromachined accelerometers

This paper reports mixed-signal front-end architecture for z-axis capacitive inertial surface-micromachined MEMS accelerometer. The method consists in capacitance to frequency to digital conversion with the aid of relaxation oscillator and high-precision digital frequency demodulator based on counters for coarse measurement and tapped delay line for fine measurement. This approach allows rapid prototyping based mainly on standard digital synthesis and automated place-and-route, what is especially important in case of CMOS integrated microsensors - the target application of the architecture.