Single-resonator, time-switched FM MEMS accelerometer with theoretical offset drift complete cancellation

Abstract

The work presents the first frequency modulated (FM) accelerometer operating in time-switched differential mode: readout is based on a double sampling of the oscillation frequency of a single resonator, consecutively biased in two different configurations in time. This technique theoretically enables zeroing of offset drift components related to the temperature coefficient of frequency (TCf), even in presence of process nonuniformities. Additionally, the TCf offset drift component can be tuned to compensate the thermal-stress component, delivering compact, ultra-low-drift, accelerometers. Experiments on various samples demonstrate repeatable sub-50μg/K drift without post-acquisition corrections, at a consumer-grade 100μg/VHz noise density.