基于漏栅极反馈技术的低相位噪声VCO设计

Design of a Low-Phase-Noise VCO with Drain-Gate Feedback Technique

提出了一种新颖的嵌有阻抗变换模块(ITB),而不具有尾电流源的压控振荡器(VCO)。ITB的引入抑制了由有源器件引起的噪声退化问题,交叉耦合晶体管基本上工作于饱和状态,抑制了LC谐振回路品质因子的降低。而且,该结构相对于传统的VCO而言,具有更容易满足的起振条件,并且保持了低电压工作下的低噪声性能。基于0.18μm CMOS工艺对该VCO进行设计并流片实现,测试结果表明,所提出的VCO振荡频率为4.82 GHz^6.1 GHz,调谐范围为23.5%,相位噪声为-122.5 dBc/Hz@1 MHz^115.6 dBc/Hz@1 MHz,电路在1 V电压供电下,消耗了1.5 mW的功耗。

A new voltage controlled oscillator(VCO)without tail current source imbedded with an impedance transformation block(ITB)has been presented.Using this ITB,the noise generation from active devices is reduced.The cross-coupled transistors remain mostly in the saturation region and prevent decreasing of LC-tank quality factor.Moreover this structure benefits from more relaxed start-up condition as compared to the conventional VCO and preserves its low phase-noise performance even in low voltage operation.This VCO is designed and implemented in 0.18μm CMOS process.The measured results show that the proposed VCO achievs a phase noise between-122.5 dBc/Hz and-115.6 dBc/Hz at 1 MHz frequency offset with 23.5%tuning range between 4.82 GHz and 6.1 GHz.The circuit consumption is 1.5 mW from the 1 V supply.