Title :
Low-motional-impedance highly-tunable I2 resonators for temperature-compensated reference oscillators
Author :
Ho, Gavin K. ; Sundaresan, Karthikeyan ; Pourkamali, Siavash ; Ayazi, Farrokh
Author_Institution :
Georgia Inst. of Technol., Atlanta, GA, USA
fDate :
30 Jan.-3 Feb. 2005
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 24kΩ 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 0.5μm CMOS process. Preliminary tests show temperature drift reduction of a 4MHz resonator from 2400ppm to 240ppm over a 90°C range.
Keywords :
CMOS integrated circuits; Q-factor; micromechanical resonators; oscillators; silicon-on-insulator; 0.5 micron; 3 to 6 MHz; CMOS process; HARPSS-on-SOI process; automatic temperature-compensating bias voltage; automatic tunable charge pump; capacitive micromechanical resonator; electrostatic tuning coefficient; highly-tunable I2 resonators; low-motional-impedance I2 resonators; oscillator interface circuit; quality factors; temperature drift reduction; temperature-compensated reference oscillators; trans-impedance amplifier; Charge pumps; Circuit optimization; Design optimization; Electrostatic measurements; Impedance measurement; Micromechanical devices; Oscillators; Q factor; Tunable circuits and devices; Tuning;
Conference_Titel :
Micro Electro Mechanical Systems, 2005. MEMS 2005. 18th IEEE International Conference on
Print_ISBN :
0-7803-8732-5
DOI :
10.1109/MEMSYS.2005.1453881
