文件名称：PCI EXPRESS 板卡设计指南
文件大小：482KB
文件格式：PDF
更新时间：2012-09-15 02:50:59
PCI EXPRESS 板卡设计指南
PCI EXPRESS 板卡设计指南: 1. Physical Interconnect Layout Design................................................ 5 1.1 Introduction ........................................................................................................ 5 1.2 Topology and Interconnect Overview .............................................................. 5 1.2.1 Card Interoperability ............................................................................................... 7 1.2.2 Bowtie Topology Considerations ............................................................................ 7 1.2.2.1 Lane Polarity Inversion.................................................................................................... 8 1.2.2.2 Lane Reversal and Width Negotiation ............................................................................. 8 1.3 Physical Layout Design Constraints............................................................... 11 1.3.1 PCB Stackup.......................................................................................................... 11 1.3.1.1 Desktop System Board and Add-in Card (4-layer) Stackup .......................................... 12 1.3.1.2 Server, Workstation and Mobile (6-layer, 8-layer and 10-layer) Stackups.................... 15 1.3.1.3 Add-in Card and Mobile (6-layer) Stackup ................................................................... 16 1.3.2 PCB Trace and Other Element Considerations ..................................................... 17 1.3.2.1 Differential Pair Width and Spacing Impacts ................................................................ 20 1.3.2.2 Differential Pair Length Restrictions and Budgets ........................................................ 23 1.3.2.3 Length Matching............................................................................................................ 24 1.3.2.4 Reference Planes............................................................................................................ 25 1.3.2.5 Breakout Area Specific Routing Guidelines .................................................................. 27 1.3.2.6 Edge Finger Design: Add-in Card ................................................................................. 29 1.3.2.7 Via Usage and Placement .............................................................................................. 30 1.3.2.8 Bends ............................................................................................................................. 32 1.3.2.9 Test Points and Probing ................................................................................................. 35 1.3.3 PCI Express Topologies ........................................................................................ 35 1.3.3.1 Interconnect Topologies for Two Components on the Baseboard ................................. 36 1.3.3.2 Interconnect Topologies for Baseboard with Add-in Card ............................................ 37 1.3.4 Passive Components and Connectors .................................................................... 38 1.3.4.1 AC Coupling Capacitors ................................................................................................ 38 1.3.4.2 Connectors ..................................................................................................................... 40 1.4 Summary........................................................................................................... 41