A 2.7-mW 1.36–1.86-GHz LC-VCO With a FOM of 202 dBc/Hz Enabled by a 26%-Size-Reduced Nano-Particle-Magnetic-Enhanced Inductor

This paper reports the first LC voltage-controlled oscillator (LC-VCO) in CMOS utilizing a novel nontraditional compact inductor with integrated vertical nano particles magnetic core (Ni-Zn-Cu) to improve the figure-of-merit (FOM) of the VCO circuit. The new magnetic-enhanced inductor, fabricated in an integrated-circuit back-end using a CMOS-compatible process, improves inductance density ( L-density) and quality factor ( Q-factor) up to 7 GHz. A 1.36-1.86-GHz VCO with a nano-ferrite-integrated inductor was fabricated in a 180-nm RF CMOS. Measurements show that the magnetic-cored inductor improves the L-density and Q-factor by 49.8% and 59.2% at 1.8 GHz, respectively, while reducing the size by 26%. The VCO achieves reduced power consumption of 2.7 mW at a 1.8-V supply, low phase noise of less than -121, and -126 dBc/Hz at 100-kHz and 1-MHz frequencies offset, and a high FOM of 202 dBc/Hz. This prototype VCO demonstrates that the new vertical-nano-magnetic-cored inductor technology is a potential solution to high-performance low-cost compact RF systems-on-chip.