A fourth-order /spl Sigma//spl Delta/ interface for micromachined inertial sensors

A high-order electromechanical /spl Sigma//spl Delta/ modulator uses additional electronic filtering in the loop to eliminate excessive in-band quantization noise inherently present in second-order implementations. The interface is fabricated in a 0.5/spl mu/m CMOS process and tested with a gyroscope and accelerometer achieving 1/spl deg//s/4Hz and 150/spl mu/g/Hz of resolution, respectively. Active chip area is 0.9mm/sup 2/ and the IC consumes a total of 18mW.