A Constant-Current-Controlled Class-C Voltage-Controlled Oscillator using Self-Adjusting Replica Bias Circuit

Teerachot SIRIBURANON  Wei DENG  Kenichi OKADA  Akira MATSUZAWA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E98-C   No.6   pp.471-479
Publication Date: 2015/06/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E98.C.471
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuits and Related SoC Integration Technologies)
Category: 
Keyword: 
low power,  low phase noise,  class-C VCO,  start-up,  CMOS,  replica-bias circuit,  

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Summary: 
This paper presents a constant-current-controlled class-C VCO using a self-adjusting replica bias circuit. The proposed class-C VCO is more suitable in real-life applications as it can maintain constant current which is more robust in phase noise performance over variation of gate bias of cross-coupled pair comparing to a traditional approach without amplitude modulation issue. The proposed VCO is implemented in 180 nm CMOS process. It achieves a tuning range of 4.8–4.9 GHz with a phase noise of -121 dBc/Hz at 1 MHz offset. The power consumption of the core oscillators is 4.8 mW and an FoM of -189 dBc/Hz is achieved.