Xilinx's recommendations on Board Routability Guidelines that are available in the Virtex-II/-II Pro User Guides are very aggressive and might not apply to every design situation. Are there more conservative designs that are available for reference?
The recommendations provided in the Virtex-II/-II Pro User Guides are aggressive. Xilinx has made these recommendations based on a less conservative design method, but Xilinx can also provide more conservative strategies on request. Xilinx typically groups routing strategies into two groups, as follows:
1. Conservative - For the conservative method, the trace width is 5 mils, and only one trace is routed between the drill holes. For this method, more board layers are needed.
2. Aggressive - For the aggressive method, the trace width is 4 mils, and there are two traces routed between the drill holes. For this method, fewer board layers are needed but more advanced PCB technology is required.
To request these recommendations, please contact Xilinx Technical Support at: