A power-optimized widely-tunable 5-GHz monolithic VCO in a digital SOI CMOS technology on high resistivity substrate

This paper describes the design and technology optimization of power-efficient monolithic VCOs with wide tuning range. Four 5-GHz LC-tank VCOs were fabricated in a 0.12-μm SOI CMOS technology that was not enhanced for RF applications. High and regular resistivity substrates were used, as were single-layer and multiple-layer copper inductors. Using a new figure-of-merit (FOMT) that encompasses power dissipation, phase noise and tuning range, our best VCO has an FOMT of -189 dBc/Hz. The measured frequency tuning range is 22 % and the phase noise is -126 dBc/Hz at 1 MHz offset for 4.5-GHz. Oscillation was achieved at 5.4-GHz at a minimum power consumption of 500 μW.