A Dual-Conduction Class-C VCO for a Low Supply Voltage

Kenichi OKADA  You NOMIYAMA  Rui MURAKAMI  Akira MATSUZAWA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E95-A   No.2   pp.506-514
Publication Date: 2012/02/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E95.A.506
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
Category: 
Keyword: 
VCO,  class-C,  dual conduction,  CMOS,  low supply voltage,  impulse sensitivity function (ISF),  

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Summary: 
This paper proposes a dual-conduction class-C VCO for ultra-low supply voltages. Two cross-coupled NMOS pairs with different bias points are employed. These NMOS pairs realize an impulse-like current waveform to improve the phase noise in the low supply conditions. The proposed VCO was implemented in a standard 0.18 µm CMOS technology, which oscillates at a carrier frequency of 4.5 GHz with a 0.2-V supply voltage. The measured phase noise is -104 dBc/Hz@1 MHz-offset with a power consumption of 114 µW, and the FoM is -187 dBc/Hz.