A low phase noise LC VCO in 65 nm CMOS process using rectangular switching technique

Abstract

A low phase noise and low power LC voltage-controlled oscillator (VCO) has been designed using a 65-mn CMOS process. The phase noise is minimized by switching the differential core using a rectangular shaped voltage waveform, which is formed by a harmonic tuned,LC tank assisted by a g(m3) boosting circuit. The g(m3) boosting circuit effectively maximizes the slope at the zero crossing point and reduces the transition time in which the switching transistor is operated at the triode region. The rectangular switching technique has improved the phase noise of the oscillator by 10 dB. The 450 mu m * 540 mu m chip consumes 4.34 mW. The proposed VCO has phase noises of -83.3, -110.7, and -131.8 dBc/Hz at 10 KHz, 100 KHz, and 1 MHz offset frequencies, respectively, from the 1.6-GHz carrier frequency.