A 12.9-to-24 GHz Dual-Mode Multi-Coil VCO Achieving 199.2 dBc/Hz Peak FoM<sub>T</sub> in 65-nm CMOS
Ya Zhao, Chao Fan, Yuanxing Peng, Chenglong Liang, Jun Yin, Pui‐In Mak, Li Geng
Abstract
This brief reports a mode-switching dual-core multi-coil voltage-controlled oscillator (VCO) with improved frequency tuning range (FTR) and phase noise (PN). Specifically, our VCO utilizes the head transformer (HT) and source center-tap inductor to enable dual-mode operation for FTR extension. Besides, the multi-coil VCO features two-port configuration, where the inherent boosted transformer voltage gain help reducing the PN injection. We also propose a compact HT layout to aid eliminating the parasitic common mode (CM) inductance. The tiny mode-selection switches at the drain terminal introduce negative resistance at the desired mode, averting the oscillation state ambiguity. The VCO fabricated in 65-nm CMOS occupies a core area of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.098~{\mathrm{ mm}}^{2}$ </tex-math></inline-formula> while dissipating 16.8 mW at a 0.7-V supply. The measured PN peaks to -129.1 dBc/Hz at 10-MHz offset throughout the entire FTR of 58% (12.9 to 24 GHz) with the corresponding peak <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm{ FoM}}_{\mathrm{ ~T}}$ </tex-math></inline-formula> of 199.2 dBc/Hz.