Process Variability Monitor for Embedded MEMS Inertial Sensors Exploiting Digital Calibration Coefficients

Abstract

MEMS inertial sensors based on capacitive comb electrodes provide very low signal amplitudes. To accurately process these signals, the connected read-out system needs to be robust against process, voltage and temperature variation. This is accomplished through digital calibration techniques, which use adaptive linear filters to correct the digital output signal. In this paper we expand the digital calibration part to introduce an innovative monitor concept for process variability. By using the signal of an available temperature sensor and the filter coefficients of the calibration system, a measure for the influence of process variability is provided. The proposed concept has successfully been verified to monitor process corners in a 350nm CMOS sensor interface.