Open AccessUltra‐low‐phase‐noise CMOS LC quadrature voltage controlled oscillator with Colpitts topology
Author(s) -
Hemmati M.J.
Publication year - 2014
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2013.3813
Subject(s) - colpitts oscillator , phase noise , voltage controlled oscillator , topology (electrical circuits) , cmos , oscillation (cell signaling) , electronic oscillator , electronic engineering , dbc , electrical engineering , voltage , vackář oscillator , engineering , chemistry , biochemistry
A new low‐phase‐noise colpitts LC quadrature voltage controlled oscillator (QVCO) is presented. The proposed QVCO is realised by coupling two differential current‐switching Colpitts oscillators in an ‘in‐phase–anti‐phase’ manner. The coupling technique between the two Colpitts LC‐voltage controlled oscillators (VCOs) has significantly improved the phase noise of the proposed circuit without using any extra elements. The oscillation frequency of the proposed LC‐QVCO is 4 GHz. The Colpitts QVCO exhibits a phase noise of −131.5 and −141.3 dBc/Hz at 1 and 3 MHz offset, respectively. By generalising the coupling scheme to more than two differential Colpitts VCOs in a loop, multiphase signals can be generated.