An Octave Tuning Range and Low Phase Noise Multi-Core Mode-Switching Oscillator Using Compact Hybrid Parallel-Series Resonator

In this article, a multi-core mode-switching voltage-controlled oscillator (VCO) using a hybrid parallel-series resonator is proposed to achieve octave tuning range, low phase noise, and area efficiency, simultaneously. By reconfiguring operating mode of the hybrid parallel-series resonator, the equivalent inductance and capacitance can be changed to synthesize three distinct frequency modes, while high resonator impedance and the constructive coupling suppresses phase noise. Meanwhile, the proposed hybrid parallel-series resonator employs the benefits of area efficiency of the series resonator without the phase noise degradation caused by mismatch and parasitics introduced by switches on taps. Prototyped in a 40-nm CMOS process, the proposed VCO displays an 86.2% tuning range from 6.4 to 16.1 GHz and a figure-of-merit-tuning (FoM_T) of 206.6 dBc/Hz. The chip consumes 5.5 to 17.5 mW power from 0.6 V supply voltage across frequency tuning range and occupies only 0.17