Quadrature VCOs Using Single-Ended Injected Injection-Locked Frequency Dividers

Sheng-Lyang JANG  Cheng-Chen LIU  Jhin-Fang HUANG  Yuan-Kai WU  Jhao-Jhang CHEN  

IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.9   pp.1226-1229
Publication Date: 2009/09/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.1226
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Electronic Circuits
CMOS,  quadrature voltage-controlled oscillator (QVCO),  capacitor-feedback injection-locked technique,  

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This letter presents a new quadrature voltage-controlled oscillator (QVCO) consisting of two n-core Colpitts voltage-controlled oscillators (VCOs) with a tail inductor. The VCOs are used as a single-ended injected injection-locked frequency divider (ILFD). The output of the tail inductor in one ILFD is injected into the injection node in the other ILFD and vice versa. The proposed QVCO has been implemented in the 0.18 µm CMOS technology. At the supply voltage of 1.0 V, the power consumption is 1.8 mW. The free-running frequency is tunable from 4.68 GHz to 5.03 GHz as the tuning voltage is varied from 0.0 V to 1.8 V. The measured phase noise is -113.58 dBc/Hz at the 1 MHz frequency offset from the oscillation frequency of 5.03 GHz and the figure of merit (FOM) of the QVCO is -185.06 dBc/Hz.