高速电路PCB中串扰的仿真分析与抑制对策

摘要

针对串扰在高速电路印刷电路板(PCB)设计中造成严重的信号完整性问题,介绍一种可尽早发现串扰引起的问题的方法。首先利用信号完整性仿真软件HyperLynx,建立两条攻击线夹一条受害线的三线平行耦合串扰仿真模型；然后通过仿真分析传输线平行耦合长度、平行耦合间距、传输线类型、信号层与地平面层之间的介质厚度等因素对串扰噪声的影响；最后综合这些影响因素,并根据PCB设计顺序,给出抑制串扰的详细措施。实践表明,这些措施对高速PCB的设计,具有实用、可靠和提高设计效率的意义。%　　Crosstalk is one of the major factors impacting signal integrity in design of high speed printed circuit boards(PCB).This paper presents a method to find out the crosstalk problem as early as possible in PCB design.Firstly,the HyperLyx simulation software is used to set up a three-line crosstalk analysis model which consists of a pair of aggressor transimission lines and their in-between victim line.Secondly,Simulation is carried out to analyze the effect of the crosstalk noises by changing the length,distance and type of the paral el coupling transmission lines,and by changing medium thickness between the signal and groud layers.Final y,the strategies used to suppress the crosstalk are sorted out based on the analysis on these impact variables and the PCB design order and rules.Practical use of these strategies in high speed PCB design indicates that the method is feasible and reliable and can improve PCB design efficiency significantly.