Mark A. Unkrich

A Temperature-Stable Film Bulk Acoustic Wave Oscillator

This letter reports a passively temperature-compensated CMOS oscillator utilizing a film bulk acoustic resonator. The resonator exhibiting an f ldr Q product of 2-4 X 1012 s-1 is composed of molybdenum, aluminum nitride, and a compensation material that has a positive temperature coefficient of Youngs modulus. The 604-MHz oscillator consumes 5.3 mW from a 3.3-V supply and achieves excellent phase noise performances of -102, -130, and -149 dBc/Hz at 1, 10, and 100 kHz carrier offsets, respectively. The oscillators temperature-dependent frequency drift is less than 80 ppm over a temperature range of -35degC to +85degC.

Film-bulk acoustic wave resonator with motion plate and method

An apparatus and method for measuring a target environmental variable (TEV) that employs a film-bulk acoustic resonator with motion plate. The film-bulk acoustic resonator (FBAR) includes an acoustic reflector formed in an FBAR wafer and a surface. A first electrode is formed on the surface of the acoustic reflector and has a surface. A piezoelectric layer is formed on the surface of the first electrode and has a surface. A second electrode is formed on the surface of the piezoelectric layer. A motion plate is suspended in space at a predetermined distance relative to the surface of the second electrode and is capacitively coupled to the FBAR.

Effects of FBAR resonator dissipated power on discrete oscillator phase noise

We present single-ended and balanced configurations of modified Colpitts voltage controlled oscillators utilizing zero drift FBARs that are compatible with high volume manufacturing. These oscillators have been built with resonators spanning frequencies between 384 MHz and 3900 MHz, demonstrating that temperature compensated FBAR is useful over a decade frequency range for oscillator applications. Over the 1 GHz to 2.5 GHz range, we have observed mean jitter less than 10 fsec (integrated over a 12 kHz to 20 MHz offset), with the best devices demonstrating performance of 5.5 fs. The resonator is 27,000 square microns in a .43 × .35 × .23 mm package. The oscillators are designed to support a temperature range from -40 to 85°C. Due to the ability of the resonator to remain linear at dissipated power values up to 25 mW, far-from-carrier phase noise as low as -185 dBc/Hz @ 10 MHz has been achieved.