A 6.4-to-16.1GHz Hybrid Parallel-Series Resonator Mode-Switching Oscillator with 206.6dBc/Hz FoM_T at 1MHz Offset in 40nm CMOS

This paper presents an octave tuning range and low phase noise multi-core voltage-controlled oscillator using a compact hybrid parallel-series resonator. By reconfiguring operating mode of the 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 retains the benefits of small area of the series resonators. The proposed oscillator is implemented in 40 nm CMOS, displays an 86.2% tuning range from 6.4 to 16.1 GHz and a state-of-the-art peak figure-of-merit-tuning $\left(\mathrm{FoM}_{\mathrm{T}}\right)$ of $206.6 \mathrm{dBc} / \mathrm{Hz}$. The chip consumes 5.5 to 17.5 mW power and occupies only $0.17 \mathrm{~mm}^{2}$.