A low-power 4-GHz CMOS colpitts quadrature voltage controlled oscillatore

In this work, a new low-power low-noise colpitts quadrature voltage controlled oscillator (QVCO) made by coupling two identical current-switching differential colpitts voltage controlled oscillators (VCO) is proposed. The coupling technique that is used to combine the two identical VCOs is first-harmonic coupling technique. In fact, the two identical differential colpitts VCOs are coupled directly in an in-phase anti-phase scheme. Therefore, the coupling elements do not increase the power consumption of the core VCOs and do not adversely affect the phase noise. The proposed circuit is designed and simulated in a commercial 0.18 μm CMOS technology. The simulated phase noise of the proposed QVCO at 1 MHz offset frequency is -124.1 dBc/Hz, at center oscillation frequency of 4 GHz. The circuit dissipates 3.53 mW from a 1.2 V supply and its frequency can be tuned from 3.78 to 4.45 GHz

کلیدواژه ها:

voltage controlled oscillator ، low-power ، low-noise ، quadrature