Summary: IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 42, NO. 6, JUNE 2007 1425
Electronically Temperature Compensated Silicon
Bulk Acoustic Resonator Reference Oscillators
Krishnakumar Sundaresan, Member, IEEE, Gavin K. Ho, Student Member, IEEE, Siavash Pourkamali, Member, IEEE,
and Farrokh Ayazi, Senior Member, IEEE
Abstract--The paper describes the design and implementation
of an electronically temperature compensated reference oscillator
based on capacitive silicon micromechanical resonators. The de-
sign of a 5.5-MHz silicon bulk acoustic resonator has been opti-
mized to offer high quality factor ( 100 000) while maintaining
tunability in excess of 3000 ppm for fine-tuning and temperature
compensation. Oscillations are sustained with a CMOS amplifier.
When interfaced with the temperature compensating bias circuit,
the oscillator exhibits a frequency drift of 39 ppm over 100 C as
compared to an uncompensated frequency drift of 2830 ppm over
the same range. The sustaining amplifier and compensation cir-
cuitry were fabricated in a 2P3M 0.6- m CMOS process.
Index Terms--Reference oscillators, MEMS resonators, MEMS
oscillators and temperature compensation.