A 1 MHz 4 ppm CMOS-MEMS oscillator with built-in self-test and sub-mW ovenization power

Abstract

A 1 MHz 4 ppm temperature-stable micro-oven μOven) controlled monolithic CMOS-MEMS oscillator has been demonstrated in this work, exhibiting heating power in sub-mW across the 100°C temperature span. The proposed novel isothermal μOven platform consists of dual heaters, one of which stabilizes the resonator temperature while the other of which serves as built-in self-test (BIST) to mimic ambient temperature, and a resistive temperature detector (RTD) for local resonator temperature monitoring. By adapting the constant-resistance (CR) feedback temperature control scheme, the integrated 1 MHz CMOS-MEMS oscillator shows a maximum frequency inaccuracy of only 4 ppm during a fast temperature ramp across the 94°C testing span (i.e., < 43 ppb/°C). The oscillator circuit shows a worst-case bias instability of 60 ppb and phase noise (PN) of −105 dBc/Hz at 1-kHz offset (Q = 1,700).