1200-MHz Fully Integrated VCO with "Turbo-Charger" Technique

Nobuyuki ITOH
Shin-ichiro ISHIZUKA

IEICE TRANSACTIONS on Electronics   Vol.E85-C    No.8    pp.1569-1576
Publication Date: 2002/08/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on High-Performance Analog Integrated Circuits)
fully integrated VCO,  SiGe,  BiCMOS,  phase noise,  

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Fully integrated VCO using the "turbo-charger" technique to improve phase noise characteristics is presented. The phase noise degradation of relatively lower oscillation frequency in tuning range was caused by oscillation amplitude lowering due to large total capacitance. On the other hand, the phase noise degradation of relatively higher frequency in tuning range was caused by excess current noise. A new "turbo-charger" circuit increased operation current to obtain sufficient transconductance of amplifier when oscillation frequency was lower to improve phase noise characteristics. The phase noise of VCO employing this technique was extremely low and stable, below -140-dBc/Hz at 3-MHz offset from oscillation frequency, in wide oscillation frequency range, approximately 200-MHz for 1200-MHz oscillation. This VCO was operated with 5.8-7.4-mA current consumption at 3-V supply voltage. The manufacturing process was 0.6-µm SiGe BiCMOS.