Low-noise smart sensor based on silicon nanowire for MEMS resistive microphone

The design of CMOS integrated circuits dedicated to hybrid integration of a MEMS resistive microphone with readout interface is presented. Audio sensing is achieved with an innovative low-cost technology that implements piezoresistive detection in MEMS devices with single crystal silicon nanowires. The complete circuit includes a custom designed analog front-end consisting of a sensor conditioning and a fourth order single bit continuous-time sigma-delta modulator (CT-ΣΔM). The complete interface circuit exhibits a current consumption of 2mA. The obtained smart-sensor features a reduced output data rate that is suitable for a wireless sensor network with direct transmission of the raw data to a remote base station.