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This work advances the research on continuous mode-reversal frequency modulated accelerometers by characterizing in depth some of their nonidealities, proposing methods for their compensation, and exploiting a renovated sensor design that enables closed-loop compensation of shock and vibrations. The scale factor nonlinearity is first investigated and compensated through a cubic calibration term, yielding a 50% larger range for a 2.5-fold larger scale factor than in former implementations. Additionally, temperature effects on the zero-g offset are compensated by exploiting the value of the low-pass filtered resonance frequency, which yields a valuable information of the silicon sensor temperature. This enables reducing the zero-g-offset temperature dependence by a factor 5 over previous works on similar structures. Finally, a closed-loop compensation of the quality factor, implemented through additional driving electrodes in the structure, guarantees a 25-fold reduction on effects of shocks and vibrations exciting the acceleration-sensitive mode. [2022-0117] [ABSTRACT FROM AUTHOR]

This work presents a long-term characterization of a newly designed microelectromechanical-system (MEMS) micromirror capable of achieving a field-of-view (FOV) of almost 94°. The process used to fabricate the device allows to combine piezoelectric (PZT) actuation and piezoresistive (PZR) sensing of the tilt angle, enabling testing under closed loop control. Consistently with the adopted design guidelines, which considered fatigue limits on the silicon springs, the tested devices are able to withstand up to 3.6 billion continuous operating cycles in an uncontrolled laboratory environment when operated in resonant mode at 500 Hz. [2020-0366] [ABSTRACT FROM AUTHOR]

This article presents a real-time clock (RTC) system based on a microelectromechanical system (MEMS) resonator coupled to an integrated circuit (IC) that implements a frequency-compensating machine. The MEMS resonator is built with a standard, industrial-grade polysilicon process characterized by a −30-ppm/K linear temperature coefficient of frequency ($TCf$) and the frequency-drift compensation is entirely carried out within the IC using a fractional frequency division. The large, but deterministic, output jitter (≈1 $\mu s_{rms}$) is then suppressed down to less than 40 $ns_{rms}$ with a low-power digital-to-time converter (DTC), whose usefulness in this kind of application is then analyzed. With a single-point temperature calibration, a ±8-ppm output frequency stability is demonstrated at ≈800-nA current consumption from a 1.2-V supply. [ABSTRACT FROM AUTHOR]