A 13.2 mW 1.9 GHz interpolative BAW-based VCO for miniaturized RF frequency synthesis

This paper presents a continuous frequency tuned bulk acoustic wave (BAW) resonator based oscillator without varactors. The frequency of oscillation is derived by interpolating between the resonant frequencies of two different resonators. Changing the interpolation factors allows a continuous tuning of the oscillation frequency between these two resonant frequencies. A proof of concept circuit was implemented in 0.4 mum CMOS and achieved a measured tuning range of more than 3 MHz with a phase noise between -134 and -109.5 dBc/Hz at 1 MHz offset while running at 3.3 V and consuming 4 mA of current. Additionally, an extended version of this circuit utilizing a bank of resonators to enhance the tuning range while keeping the power constant is introduced.