26.5 A 0.1-to-0.2V Transformer-Based Switched-Mode Folded DCO in 22nm FDSOI With Active Step-Down Impedance Achieving 197dBc/Hz Peak FoM and 40MHz/V Frequency Pushing

Abstract

The continuous improvement in ultra-low-power/voltage (ULP/V) circuits paves the way for new near-battery-free IoE applications. In this work, we propose an LC oscillator that can significantly improve phase-noise (PN) performance and the figure of merit (FoM) at ULV supply levels. The structure is applied to a 4.15-to-4.97GHz switched-mode DCO that operates from a less-than-100mV supply and achieves a peak FoM of 197dBc/Hz at a 150mV supply.