Abstract:
Aiming at the deficiency of signal integrity for the Printed Circuit Board(PCB) design of high-density Fourteen Data Rate(FDR) interconnection switch,this paper proposes a solution scheme in the aspects of material selection,stackup assignment,wiring and anti-crosstalk.The material for PCB board manufacture and the maximum channel length are determined based on the characteristics of three types of typical high-speed material in conductor loss and dielectric loss.Moreover,the wiring policy within the BGA area and stackup are designed according to the amount of wires as well as their width requirements.Based on the theoretical analysis and calculation,the paper proposes some wiring guidelines,such as the width of the differential lines,the space between the differential lines,the placement of the differential via hole and the minimum distance from the differential via hole to the partition lines of the power layer.Under the implementation limitation,some tradeoff policies are adopted by using the striplines in wiring and reserving one side of the stub without backdrill.Simulation experimental results show that the FDR interconnection switch board designed according to the guidelines mentioned above is successfully used in several supercomputer systems including TianHe-2,and it solves the problems of signal integrity for FDR high-speed PCB design.
Key words:
FDR interconnection,
high-speed board material,
high-speed signal,
stackup,
crosstalk,
stub,
differential via hole
摘要： 针对高密度FDR互连交换板PCB设计在信号完整性方面的不足,从工程实现的角度对板材选取、叠层设计、布线规则、抗干扰措施等问题进行分析,给出完整的解决方案。对3种典型高速板材的阻性衰减和介质衰减进行量化分析,确定设计方案的板材及最大通道长度。根据BGA区域走线数量和间距要求,明确BGA区域间隔出线方式和叠层结构。通过理论分析和计算,确定差分线的线宽、线间距、差分过孔设置、差分过孔距离电源分割线最小距离等布线规则。考虑工程实施条件的限制,提出使用微带线布线、保留一侧残桩不背钻等折中处理措施。仿真实验结果表明,基于以上规则设计的FDR互连交换板已应用于包括“天河二号”在内的多款高性能计算机系统,有效解决了FDR高速PCB设计遇到的各种信号完整性问题。
关键词:
FDR互连,
高速板材,
高速信号,
叠层,
串扰,
残桩,
差分过孔
CLC Number: