低相位噪声CMOS环形压控振荡器的研究与设计

Design of Low Phase Noise CMOS Ring Voltage Controlled Oscillator

针对个人电脑和通讯系统对频率合成器中振荡器的低相位噪声的要求,对基本的环形振荡器结构进行改进,设计了两种宽带低相位噪声CMOS环形压控振荡器(VCO),在800 MHz振荡频率、1 MHz频偏下,测试的相位噪声分别为-123 dBc/Hz和-110 dBc/Hz。两个VCO的调谐范围分别为450～1 017 MHz和559～935 MHz。

In order to satisfy the demand of frequency synthesizers in PC and communication systems for low phase noise, 2 broad-band, low-noise 800-MHz voltage controlled oscillators （VCO） was designed and fabricated in 0. 7μm CMOS technology. The circuit structures were improved based on the basic inverter and differential struc- ture, respectively. Measured results showed that the two VCO＇s had a phase noise of -123 dBc/Hz and -110 dBc/ Hz, respectively, at 1 MHz offset from the carrier frequency, while operating at 800 MHz. As the control voltage changed, the VCO＇s had a tuning range from 450 MHz to 1 017 MHz, and from 559 MHz to 935 MHz, respectively.