基于可调谐LC谐振回路的双频VCO

A Dual-band VCO Based on Tuned LC-tank

采用嵌有交叉耦合晶体管对的LC谐振回路结构,利用其固有的多种振荡模式,设计了一款用于多标准射频收发器的压控振荡器(VCO)。该电路通过变容管开关偏置的作用,操作于高频串联谐振和低频并联谐振两个模式,并且输出的所有频率都与谐波无关。通过累积型MOS变容管的调谐作用对LC谐振回路的节点阻抗进行改变,实现振荡器在两个模式下的切换。基于TSMC 0.18μm 1P6M CMOS工艺实现文中所提出的VCO,测试表明:该VCO的振荡频率为2.92 GHz^3.23 GHz和7.31 GHz^8.2 GHz,该两个频带的相位噪声分别为-128.22 d Bc/Hz@1 MHz和-123.2 d Bc/Hz@1 MHz。

By exploiting the intrinsic multiple oscillation modes of LC resonator with cross-coupled transistor pair,a differential VCO is designed for multi-standard RF transceivers. It operates at the high frequency series-resonant and low-frequency parallelresonant mode via varactor switching bias. Both frequencies are not harmonically related. Accumulation-mode MOS varactor tuning changes the net impedance of LC-tank to shift the oscillations from one resonance mode to another. The proposed VCO has been implemented with the TSMC 0.18 μm 1P6 M CMOS technology and it can generate differential signals in the frequency range of 2.92 GHz ~ 3.23 GHz and 7.31 GHz ~ 8.2 GHz. The measured phase noise is-128.22 d Bc/Hz and-123.2 d Bc/Hz at a 1 MHz offset,respectively.