A fully integrated w-band push-push CMOS VCO with low phase noise and wide tuning range
A fully integrated w-band push-push CMOS VCO with low phase noise and wide tuning range
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具有低相位噪声和宽调谐范围的全集成 W 频段推-推 CMOS VCO
DOI：
10.1109/tuffc.2011.1951
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发表时间：
2011
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提出了一种适用于低相位噪声、宽调谐范围推挽式压控振荡器（VCO）的电路拓扑。通过在交叉耦合对的漏极和源极终端之间连接变容二极管，有效地增加了调谐范围，改善了相位噪声。此外，在VCO内核和测试缓冲器之间插入一个小电容，以减少VCO内核上的负载效应。此外，增强的二次谐波输出信号在变容二极管的中间提取，从而消除了VCO的二次谐波输出端口处的RF扼流圈，并减小了芯片尺寸。基于所提出的结构，在0.18 μ mCMOS上制作的VCO具有6.35%的调谐范围。VCO内核工作在1.2 V电源电压下，直流功耗为7.5 mW，在77.8 GHz载波100 kHz和1 MHz偏移处测得的相位噪声分别为-75 dBc/Hz和-91.5 dBc/Hz。与先前发表的70 GHz以上硅基压控振荡器相比，该工作可以同时实现低相位噪声、宽调谐范围和低直流功耗，从而获得上级品质因数（FOM）和考虑调谐范围的更好品质因数（FOMτ）。此外，该全集成压控振荡器也是目前已发表的0.18 μ mCMOS压控振荡器中工作频率最高的。
A circuit topology suitable for a low-phase-noise wide-tuning-range push-push voltage-controlled oscillator (VCO) is proposed in this paper. By applying varactors connected between drain and source terminations of the cross coupled pair, the tuning range is effectively increased and the phase noise is improved. Moreover, a small capacitor is inserted between the VCO core and testing buffer to reduce loading effects on the VCO core. Furthermore, the enhanced second-harmonic output signal is extracted at middle of the varactors, leading to the elimination of RF choke at VCO's second-harmonic output port and a reduced chip size. Based on the proposed architecture, this VCO fabricated in 0.18-μm CMOS exhibits a measured 6.35% tuning range. Operating at a supply voltage of 1.2 V, the VCO core consumes 7.5-mW dc power, and the measured phase noise is -75 dBc/Hz and -91.5 dBc/Hz at 100-kHz and 1-MHz offsets from the 77.8 GHz carrier, respectively. Compared with previously published silicon-based VCOs over 70 GHz, this work can simultaneously achieve low phase noise, wide tuning range, and low dc power consumption, leading to a superior figure of merit (FOM), and better figure of merit considering the tuning range (FOMτ). In addition, this fully integrated VCO also demonstrates the highest operation frequency among previously published 0.18 μm CMOS VCOs.