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Summary: LOW-MOTIONAL-IMPEDANCE HIGHLY-TUNABLE I2
RESONATORS FOR TEMPERATURE-
COMPENSATED REFERENCE OSCILLATORS
Gavin K. Ho, Krishnakumar Sundaresan, Siavash Pourkamali, Farrokh Ayazi
Georgia Institute of Technology, Atlanta, Georgia, USA
ABSTRACT
A new capacitive micromechanical resonator design
optimized for high Q, low motional impedance, and large
tuning range is presented. The I2
resonator was fabricated
using a conservative, by present standards, HARPSS-on-
SOI process, and demonstrated quality factors up to 57000
in vacuum. From the designed resonators between 3MHz
and 6MHz, the lowest measured impedance is 2.4k and
the largest electrostatic tuning coefficient is -10ppm/V2
. An
oscillator interface circuit comprising of a trans-impedance
amplifier and an automatic tunable charge pump providing
an automatic temperature-compensating bias voltage was
also designed and fabricated in a standard 0.5Pm CMOS
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