前馈环形振荡器的结构与相位噪声研究

基于高速串行通信系统中锁相环和时钟数据恢复电路的需求,研究了前馈环形振荡器的结构与工作原理;在传统结构的基础上,将前馈路径耦合至主路径反相器的源极,可以提高输出信号的边沿速率;最后基于Hajimiri模型的脉冲灵敏度函数进行分析,提出的结构有效降低了热噪声和闪烁噪声的引入.在28 nm CMOS工艺下设计了单源极前馈型...

Structure and phase noise of feedforward ring oscillator

Based on the requirement of PLL and clock data recovery circuit in SerDes system, the structure and working principle of feedforward ring oscillator are discussed. On the basis of the traditional structure, the feedforward path is coupled to the source of the main path inverter, which can improve the edge rate of the output signal. Finally, based on the impulse sensitivity function of Hajimiri model, the proposed structure effectively reduces the introduction of thermal noise and flicker noise. Single-source feedforward and dual-source feedforward ring oscillators are designed in 28 nm CMOS process. The simulation results show that when the oscillation frequency is 2.5 GHz, the phase noise of two new structures are -99 dBc/Hz@1 MHz and -105 dBc/Hz@1 MHz respectively, and the FoM are 163 dBc/Hz and 164 dBc/Hz respectively.