Low-power three-path inductor class-C VCO without any dynamic bias circuit

A 2.48 GHz class-C voltage controlled oscillator (VCO) without any dynamic back bias circuit is presented. The VCO uses three-path high Q-factor inductor as the low loss resonator and class-C cross-coupled nMOSFET pairs for high dc/RF conversion efficiency and direct cross-coupled pMOSFET for dc current reuse. At the supply voltage of 1.2 V, the core power consumption is 0.24 mW. The phase noise of the VCO is −124 dBc/Hz and the VCO figure of merit is −197.0 dBc/Hz. The VCO was implemented in the TSMC standard 0.18 μm SiGe BiCMOS process and occupies a die area of 0.799 × 0.809 mm2.