CMOS quadrature VCO using a passive coupling device

This article presents a new fully-integrated quadrature voltage-controlled oscillator (QVCO), which consists of two differential VCOs coupled via an inductor-ring. The proposed CMOS QVCO has been implemented with the TSMC 0.18-μm CMOS technology and the die area is 0.693 × 0.976 mm2. At the supply voltage of 0.7 V, the total power consumption is 2.58 mW. The free-running frequency of the QVCO is tunable from 5.15 to 5.55 GHz as the tuning voltage is varied from 0 to 0.7 V. The measured phase noise at 1 MHz frequency offset is −120.88 dBc/Hz at the oscillation frequency of 5.28 GHz and the figure of merit of the proposed QVCO is −191.21 dBc/Hz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:310–313, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27283