A Wide-Tuning-Range VCO with Small VCO-Gain Variation for Multi-Band W-CDMA RFIC

Takahiro NAKAMURA  Tomomitsu KITAMURA  Nobuhiro SHIRAMIZU  Toru MASUDA  

IEICE TRANSACTIONS on Electronics   Vol.E96-C   No.6   pp.790-795
Publication Date: 2013/06/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E96.C.790
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuits and Related SoC Integration Technologies)
VCO,  VCO gain,  WCDMA,  and RFIC,  

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A wide-tuning-range LC-tuned voltage-controlled oscillator (LC-VCO) – featuring small VCO-gain (KVCO) variation – has been developed. For small KVCO variation, a serial LC-resonator that consists of an inductor, a fine-tuning varactor, and a capacitor bank was added to a conventional parallel LC-resonator that uses a capacitor bank scheme. The resonator was applied to a 3.9-GHz VCO for multi-band W-CDMA RFIC fabricated using 0.25-µm Si-BiCMOS technology. The VCO exhibited KVCO variation of only 21%, which is one third that of a conventional VCO, with a 34% tuning range. The VCO also exhibited a low phase noise of -121 dBc/Hz at 1-MHz offset frequency and a low current consumption of 6.0 mA.