Series-resonant micromechanical resonator oscillator

Abstract

A 10-MHz series resonant micromechanical resonator oscillator has been demonstrated using a custom-designed, single-stage, zero-phase-shift sustaining amplifier together with a clamped-clamped beam micromechanical resonator, designed with a relatively large width of 40 /spl mu/m to achieve substantially lower series motional resistance R/sub x/ and higher power handling than previous such devices. Using automatic level control (ALC) circuitry to remove an unexpected 1/f/sup 3/ close-to-carrier phase noise component, this oscillator achieves a phase noise density of -95 dBc/Hz at 1 kHz offset from the carrier, while consuming only 820 /spl mu/W of power.