A 1.2-3.2 GHz CMOS VCO IC Utilizing Transformer-Based Variable Inductors and AMOS Varactors

Qing LIU  Yusuke TAKIGAWA  Satoshi KURACHI  Nobuyuki ITOH  Toshihiko YOSHIMASU  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E94-A   No.2   pp.568-573
Publication Date: 2011/02/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E94.A.568
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
AMOS varactor,  CMOS,  transformer-based variable inductor,  wide-tuning range,  

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A novel resonant circuit consisting of transformer-based switched variable inductors and switched accumulation MOS (AMOS) varactors is proposed to realize an ultrawide tuning range voltage-controlled-oscillator (VCO). The VCO IC is designed and fabricated using 0.11 µm CMOS technology and fully evaluated on-wafer. The VCO exhibits a frequency tuning range as high as 92.6% spanning from 1.20 GHz to 3.27 GHz at an operation voltage of 1.5 V. The measured phase noise of -120 dBc/Hz at 1 MHz offset from the 3.1 GHz carrier is obtained.