VCO论文——A Low Phase-Noise CMOS VCO With.pdf

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 54, NO. 7, JULY 2006 2917 A Low Phase-Noise CMOS VCO With Harmonic Tuned LC Tank Huijung Kim, Seonghan Ryu, Yujin Chung, Jinsung Choi, and Bumman Kim , Senior Member, IEEE Abstract— This paper presents a phase-noise reduction tech- nique for voltage-controlled oscillators (VCOs) using a harmonic tuned (HT) LC tank. The phase-noise suppression is achieved through almost rectangular-shaped voltage at the switching differ- ential cell, which effectively maximizes the slope of the switching cell output voltage at a zero crossing point. In addition, the pro- posed technique also suppresses the down-conversion of the noise around the second harmonic frequency by the second harmonic short of the tank. One second HT VCO and two third HT VCOs are designed and implemented to evaluate the concept using a - and - m CMOS process. The ?gure-of-merit (FOM) of the second HT VCO, third HT VCO1, and third HT VCO2 are , , and , respectively. The best FOM performance of the VCO has phase noises of , , and dBc/Hz at 100-kHz, 1-MHz, and 3-MHz offset frequencies at the 2-GHz carrier, respectively. This VCO consumes mA from a -V supply with the silicon area of 500 m 750 m. Index Terms— CMOS, harmonic tuned (HT) LC tank, lowphase noise, voltage-controlled oscillator (VCO). I. I NTRODUCTION A MAJO