Degraded Frequency-Tuning Range and Oscillation Amplitude of LC-VCOs due to the Nonquasi-Static Effect in MOS Varactors

Masataka MIYAKE  Daisuke HORI  Norio SADACHIKA  Uwe FELDMANN  Mitiko MIURA-MATTAUSCH  Hans Jurgen MATTAUSCH  Tatsuya OHGURO  Takahiro IIZUKA  Masahiko TAGUCHI  Shunsuke MIYAMOTO 

Publication
IEICE TRANSACTIONS on Electronics  Vol.E92-C  No.6  pp.777-784
Publication Date: 2009/06/01
Online ISSN: 1745-1353
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuits and Related SoC Integration Technologies)
Category: 
Keyword: 
accumulation-mode,  MOS varactor,  carrier-transit delay,  nonquasi-static effect,  compact model,  surface potential,  circuit simulation,  LC-VCO,  frequency-tuning range,  FTR,  oscillation amplitude, 

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Summary: 
Frequency dependent properties of accumulation-mode MOS varactors, which are key elements in many RF circuits, are dominated by Non-Quasi-Static (NQS) effects in the carrier transport. The circuit performances containing MOS varactors can hardly be reproduced without considering the NQS effect in MOS-varactor models. For the LC-VCO circuit as an example it is verified that frequency-tuning range and oscillation amplitude can be overestimated by over 20% and more than a factor 2, respectively, without inclusion of the NQS effect.