| | |
Summary: A Two-Chip, 4-MHz, Microelectromechanical
Reference Oscillator
Krishnakumar Sundaresan, Gavin K. Ho, Siavash Pourkamali and Farrokh Ayazi
School of Electrical and Computer Engineering
Georgia Institute of Technology, Atlanta, GA 30332
krishnak@ece.gatech.edu, ayazi@ece.gatech.edu
Abstract -- The paper describes a 4-MHz temperature
compensated reference oscillator based on a capacitive silicon
micro-mechanical resonator. The design of the resonator has
been optimized to offer large quality factors (22000), while
maintaining tunability in excess of 3000ppm for fine tuning
and temperature compensation. Oscillations are sustained with
a CMOS amplifier and temperature compensation is
performed with a novel resonator bias generator. When
interfaced with the bias circuit, the oscillator exhibits a
temperature drift of 380ppm over a 90ºC range, a 6X
improvement in stability over an uncompensated oscillator.
The sustaining amplifier and compensation circuitry were
fabricated in a 2P3M 0.5µm CMOS process. The oscillator is
designed to prototype highly stable, low phase-noise reference
|
