Low-voltage/low-power 7-GHz transformer-coupled current-reused CMOS QVCO with wide tuning range

Yan Ru Tseng, Tzuen Hsi Huang, Shang Hsun Wu

Research output: Contribution to journalArticlepeer-review


In this article, we report the design of a transformercoupled current-reused quadrature voltage-controlled oscillator (QVCO) having low-voltage operation, low-power consumption, and a wide tuning range. An improved trifilar transformer that is fabricated by symmetrically interlacing two half circle secondary coils between the turns of the primary coil is proposed to provide a higher magnetic coupling factor. A QVCO integrated with such a trifilar transformer is implemented using 0.18-lm RF CMOS technology. When the QVCO is operated at a supply voltage of 1V at 7.263 GHz, the measured phase noise is -111.4 dBc/Hz at a 1-MHz offset. Further, the QVCO core draws only 1.58 mW. The total tuning range is -510 MHz over the whole tuning range (from 0 to 1.8 V). The calculated figure of merit is 186.6 dB and the power-frequency-tuning-normalized factor is -9.4 dB. As compared to the reported data in a previous study, a 28.2% reduction in power consumption and a 54.5% increase in tuning range can be achieved.

Original languageEnglish
Pages (from-to)797-801
Number of pages5
JournalMicrowave and Optical Technology Letters
Issue number4
Publication statusPublished - 2010 Apr 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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