Low phase noise 70 MHz micromechanical reference oscillators

Abstract

70 MHz temperature compensated micromechanical resonator oscillators (TCMRO) have been demonstrated by combining non-intrusive, temperature insensitive flexural beam resonator with Q above 16,000 and low-noise off chip electronics. Benefiting from the robust resonator design, the oscillators output power exceeds 0 dBm without post power amplifiers. It is 30 dB higher than that of the clamped-clamped beam oscillators. Therefore, the oscillator shows -130 dBc far-from-carrier and -117 dBc/Hz 1kHz away from carrier phase noise performance, which is equivalent to -128dBc/Hz for 19.2MHz and -132dBc/Hz for 12 MHz oscillators at the same offset. Moreover, with electrical stiffness temperature compensation features, this oscillator shows greatly improved temperature coefficient of frequency (TC/sub f/) in simulation.