A monolithically integrated three axial accelerometer using stress sensitive CMOS differential amplifiers

A CMOS integrated three axial accelerometer based on a novel detection approach is presented. Applied acceleration is translated to voltage signal with "stress sensitive differential amplifier" (SSDA). Outputs of X, Y and Z axis SSDAs are selected by a 3-ch analog multiplexer, and are amplified by a fully differential amplifier. The chopper stabilization technique was applied to them in order to improve the signal to noise ratio of the total system. The 192 mV/G of Z axis, and 23 mV/G of X and Y axis overall sensitivity were obtained. A time division multiplex technique which makes it possible to detect three components at the same time, can be realized with the accelerometer, if sample and hold circuits and additional signal processing circuits are combined with the accelerometer.