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

Research output: Contribution to journalArticle

6 Citations (Scopus)


A novel resonant circuit consisting of transformer-based switched variable inductors and switched accumulationMOS (AMOS) varactors is proposed to realize an ultrawide tuning range voltage-controlledoscillator (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 1.5V. The measured phase noise of -120 dBc/Hz at 1MHz offset from the 3.1 GHz carrier is obtained.

Original languageEnglish
Pages (from-to)568-573
Number of pages6
JournalIEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Issue number2
Publication statusPublished - 2011 Feb



  • AMOS varactor
  • CMOS
  • Transformer-based variable inductor
  • Wide-tuning range

ASJC Scopus subject areas

  • Signal Processing
  • Computer Graphics and Computer-Aided Design
  • Electrical and Electronic Engineering
  • Applied Mathematics

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