A Low-Phase-Noise Multi-Phase Oscillator Based on Left-Handed LC-Ring

This paper presents a distributed multi-phase oscillator based on left-handed LC-ring. In contrast to traditional designs that couple multiple LC-tanks through MOSFETs, it uses an LC-ring as a single high-order resonator that generates multi-phase resonant signal. By avoiding coupling MOSFETs which deteriorate phase noise significantly, it can synthesize multiple phases while maintaining the same phase-noise figure-of-merit (FoM) as a single-stage LC oscillator. This also provides a systematic way of trading power for phase noise. The dynamics and the phase noise of the LC-ring oscillator are analyzed based on a mode-decomposition model. We also address the duality of left-/right-handed resonator in the context of oscillator in detail. These analysis was verified by prototypes in a 0.13 μm CMOS process with 0.5 V supply voltage: a four-stage LC-ring oscillator at 5.12 GHz draws 8 mA current and achieves a phase noise of -121.6 dBc/Hz@600 kHz, while a single-stage one at 5.34 GHz draws 2 mA and achieves -116.1 dBc/Hz@600 kHz. There is a good agreement among analysis, simulation, and measurement.