高速高密度PCB的SI问题

随着数字电子产品向高速高密度发展,SI问题逐渐成为决定产品性能的因素之一,高速高密度PCB设计必须有效应对SI问题。在PCB级,影响SI的3个主要方面是互联阻抗不连续引起的反射、邻近互联引起的串扰和逻辑器件开关引起的SSN。从高速高密度PCB设计的角度,在介绍SI问题的产生的基础上,着重分析了反射、串扰和SSN的机理、特性及对SI的影响。分析结论对高速高密度PCB设计实践具有参考作用。

SI problems in high-speed and high-density PCBs

High-speed and high-density is a striking trend of digital electronic products, SI （signal integrity） has key impacts on performance of the products, and it＇s critically important to fix SI problems in high-speed and high-density PCB designs. At the level of PCB, the three main issues of concern for SI are reflections occurring because of interconnect discontinuities, noise induced by neighbouring connections （crosstalk）,andSSN （simuhaneous switching noise） caused by switehing of the digital devices. On the purpose of high-speed and high-density PCB designs, the root cause of SI problems are introduced, and the mechanisms, characteristics, and effects on SI of the three main issues of concem for SI are analyzed. The discussions and conclusions are useful for guiding the high-speed and high-density PCB design practices.