Low-power VCO with phase-noise improvement in 0.18 μm CMOS technology

A low-power 5.25 GHz voltage-controlled oscillator (VCO) with phase-noise improvement is designed in a 0.18 μm CMOS 1P6M process. Owing to the use of a larger value of parallel capacitor, an additional harmonic-suppressed capacitor, and an appropriate bulk bias voltage of transistor, a good figure of merit of -190 dBc/Hz can be achieved without extra chip area and CMOS process steps. The fabricated VCO operates from 5.12 to 5.36 GHz with a core power consumption of 1.9 mW and active chip area of 0.15 mm². The measured phase noise at 1 MHz offset is about -119 dBc/Hz.