PCB布线中的过孔和电容效应分析和结构优化

摘要

Via hole and capacitance are common disconnecting structures in multi-layer PCB wiring. As signal line travels among different layers,signal integrity problems from parasitic capacitance and inductance between via hole and backflow layer occurs. The AC coupling capacitances on common transmission lines will also bring in a structure of the resistance mutation , which will result in reflection and other related problems. By modeling and simulation for via holes on multi-layer PCB ,the ef-fects of different variables on performance of the via holes were studied to assist the analysis of signal integrity. Compensation in different modes is conducted for the resistance mutation of capacitance. The simulation results were verified by the related tests. The solution to improve the signal transmission properties was obtained.%在多层PCB布线中,过孔和电容是常见的不连续结构.信号线在不同平面间转换传输路径时,过孔与回流层之间的寄生电容与寄生电感将引起信号完整性的相关问题;而常用的传输线上的AC耦合电容等,引入了阻抗突变的结构,由此带来了反射等相关问题.通过对多层PCB上的过孔进行建模仿真,研究不同变量对过孔性能的影响趋势,以协助信号完整性问题的分析;通过对电容阻抗突变处进行不同形式的补偿,仿真和测试结果相验证,得到提高信号传输质量的解决方案.