An AM-PM Noise Mitigation Technique in Class-C VCO

Kento KIMURA  Aravind THARAYIL NARAYANAN  Kenichi OKADA  Akira MATSUZAWA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E98-C   No.12   pp.1161-1170
Publication Date: 2015/12/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E98.C.1161
Type of Manuscript: PAPER
Category: Electronic Circuits
Keyword: 
VCO,  Class-C,  AM-PM conversion,  parasitic capacitance,  cross coupled pair,  noise sensitivity,  

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Summary: 
This paper presents a 20GHz Class-C VCO using a noise sensitivity mitigation technique. A radio frequency Class-C VCO suffers from the AM-PM conversion, caused by the non-linear capacitance of cross coupled pair. In this paper, the phase noise degradation mechanism is discussed, and a desensitization technique of AM-PM noise is proposed. In the proposed technique, AM-PM sensitivity is canceled by tuning the tail impedance, which consists of 4-bit resistor switches. A 65-nm CMOS prototype of the proposed VCO demonstrates the oscillation frequency from 19.27 to 22.4GHz, and the phase noise of -105.7dBc/Hz at 1-MHz offset with the power dissipation of 6.84mW, which is equivalent to a Figure-of-Merit of -183.73dBc/Hz.