A Phase Noise Optimized 4 GHz Differential Colpitts VCO

Hee-Tae AHN  Jinwook BURM  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E93-C   No.3   pp.420-422
Publication Date: 2010/03/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E93.C.420
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Electronic Circuits
Keyword: 
low phase noise,  amplitude control,  differential Colpitts VCO,  

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Summary: 
This letter presents the design and analysis of phase noise optimization of a 4-GHz differential Colpitts voltage-controlled-oscillator (VCO). A low phase noise is achieved by a Colpitts oscillator and a VCO bias optimization using an amplitude control method. The measured phase noise is -134.8 dBc/Hz at 1.25 MHz offset frequency from 4 GHz operating frequency. The VCO is implemented using 0.24 µm SiGe BiCMOS process with integrated copper inductors. The wide VCO frequency range covers both PCS and IMT bands and draws about 15.9 mA from a 2.7 V power supply.