A low-power 6.3 GHz FBAR overtone-based oscillator in 90 nm CMOS technology

Film bulk acoustic wave resonators (FBARs) are useful to make very selective filters and low-power oscillators in the low-GHz frequency region. To extend the useful range of FBARs to higher frequencies, we demonstrate the use of an FBAR at an overtone frequency. A Colpitts oscillator has been designed by combining via wire bonding 90 nm CMOS circuitry with an FBAR on a separate chip. The simulated oscillation frequency of the oscillator is 6.3 GHz with a power consumption of 475 muW in the core. The oscillator achieves phase noise of-110 dBc/Hz at 1 MHz offset from the carrier. To the authors´ knowledge this is the first FBAR overtone- based oscillator in the low-GHz range.