An integrated CMOS micromechanical resonator high-Q oscillator

C.T.-C. Nguyen, R.T. Howe
1999 IEEE Journal of Solid-State Circuits  
A completely monolithic high-Q Q Q oscillator, fabricated via a combined CMOS plus surface micromachining technology, is described, for which the oscillation frequency is controlled by a polysilicon micromechanical resonator with the intent of achieving high stability. The operation and performance of micromechanical resonators are modeled, with emphasis on circuit and noise modeling of multiport resonators. A series resonant oscillator design is discussed that utilizes a unique,
more » ... le transresistance sustaining amplifier. We show that in the absence of an automatic level control loop, the closed-loop, steady-state oscillation amplitude of this oscillator depends strongly upon the dc-bias voltage applied to the capacitively driven and sensed resonator. Although the high-Q Q Q of the micromechanical resonator does contribute to improved oscillator stability, its limited power-handling ability outweighs the Q Q Q benefits and prevents this oscillator from achieving the high short-term stability normally expected of high-Q Q Q oscillators.
doi:10.1109/4.753677 fatcat:awv63erwuvgbljn4xys7a3xi5m