A 47.6–71.0-GHz 65-nm CMOS VCO Based on Magnetically Coupled $\pi $-Type LC Network

Abstract

A wide tuning range millimeter-wave voltage-controlled oscillator (VCO) based on a magnetically coupled $\pi $ -type LC network in 65-nm CMOS is proposed. By configuring the switched negative-resistance unit, the VCO can oscillate at the even mode or the odd mode of the magnetically coupled $\pi $ -type LC network, thus the tuning range is widened without introducing the switch loss into the resonator. The proposed VCO achieves a measured continuous tuning range of 39%, from 47.6 to 71.0 GHz. The measured phase noise for a 47.6-GHz carrier at the even mode and 56.2-GHz carrier at the odd mode are $-{\hbox{110.3}}$ and $-{\hbox{107.3 dBc/Hz}}$ at 10-MHz offset with a corresponding ${\rm FOM}_{\rm T}$ of $-{\hbox{185.5}}$ and $-{\hbox{183.9 dBc/Hz}}$ , respectively. The measured phase noise in the whole frequency tuning range varies from $-{\hbox{101.7}}$ to $-{\hbox{113.4 dBc/Hz}}$ at 10-MHz offset, while the corresponding figure-of-merit (FOM) and ${\rm FOM}_{\rm T}$ vary from $-{\hbox{167.8}}$ to $-{\hbox{179.0 dB}}$ and $-{\hbox{179.6}}$ to 190.6 dB, respectively. The VCO core consumes 8.9–10.4-mA current from 1.0-V power supply and 320 $\,\times \,$ 230 $\mu {\hbox{m}} ^{2}$ die area.