Temperature Compensated IBAR Reference Oscillators

This work presents a two-chip automatically temperature-compensated micromechanical IBAR reference oscillator with a temperature drift of 39ppm over 100 ° C. Temperature compensation is provided by a parabolic V
P
correction scheme and provides 10X improvement over previously reported results. Tunable 6MHz, 10MHz, and 20MHz resonators were characterized with 2000– 4500ppm tuning and Q up to 119000. Motional impedances as low as 218Ω were extracted from measurement data with V
P
= 18V. The interface IC for temperature compensation and oscillation consumes only 1.9mW. Measurements also show that temperature compensation of a 10MHz resonator with 65nm gaps is possible with less than 5V.