基于电流源开关技术的双频VCO设计

Design of a Dual-Band VCO Using a Current-Source Switching Topology

基于0.18-μm CMOS工艺,采用电流源开关技术设计实现了一种双频压控振荡器(VCO).低频带和高频带振荡信号分别采用Colpitts模式和交叉耦合对(CCP)模式实现,不同于传统的采用谐振回路开关技术的双频VCO,所提出的VCO合成了Colpitts模块和CCP模块,避免了谐振回路额外的损耗,降低了电路功耗。设计实现的VCO芯片面积为0.97×0.81 mm^2,测试结果表明当VCO工作于Colpitts模式下时,功耗为7.2 mW,在5.4 GHz振荡频率下,相位噪声为-118.1 dBc/Hz;工作于CCP模式下时,功耗为9.1 mW,在20.4 GHz振荡频率下,相位噪声为-106.1 dBc/Hz。

In this paper,a dual-band voltage controlled oscillator（DVCO） using a current-source switching topology is designed,implemented,and verified in a 0.18-μm CMOS technology.The low- and high-frequency bands are obtained by the Colpitts mode oscillation and the cross-coupled pairs（CCPs）mode oscillation,respectively.Unlike conventional dual-band VCOs realized by resonator-switching topologies,the proposed VCO is based on the composite Colpitts and CCP architecture to avoid additional losses in the resonator,or lower its power consumption.The fabricated VCO occupies a chip area of0.97 x 0.81 mm^2.Measurements show that the VCO operating in the Colpitts mode provides a phase noise of- 118.1 dBc/Hz at 1 MHz offset from the 5.4 GHz oscillation frequency under 7.2-mW power consumption.When the VCO is operating in the CCP mode,it provides a phase noise of-106.1 dBc/Hz at 1 MHz offset from the 20.4 GHz oscillation frequency with 9.1 mW power dissipation.