PCB Design Considerations - 2022.1 English

UltraFast Design Methodology Guide for Xilinx FPGAs and SoCs (UG949)

Document ID
UG949
Release Date
2022-06-08
Version
2022.1 English
The PCB should be designed considering the fastest signal interfacing with the device. These high-speed signals are extremely sensitive to trace geometry, vias, loss, and crosstalk. These aspects become even more prominent for multi-layer PCBs. For high-speed interfaces perform a signal integrity simulation. A board redesign with improved PCB material or altered trace geometries might be necessary to obtain the desired performance.

Xilinx recommends following these steps when designing your PCB:

  1. Review the following device documentation:
    • PCB Design Guide for your device.
    • Board design guidelines in the transceiver user guide for your device.
  2. Review memory IP and PCIe® design guidelines in the IP product guides.
  3. Use the Vivado tools to validate your I/O planning:
    • Run simultaneous switching noise (SSN) analysis.
    • Run built-in DRCs.
    • Export I/O buffer information specification (IBIS) models.
  4. Run signal integrity analysis as follows:
    • For gigabit transceivers (GTs), run Spice or IBIS-AMI simulations using channel parameters.
    • For lower performance interfaces, run IBIS simulation to check for issues with overshoot or undershoot.
  5. Use the Xilinx Power Estimator (XPE) spreadsheet tool (download at www.xilinx.com/power) with Process set to Maximum to generate an early estimate of the power consumption for the design.
  6. Complete and adhere to the schematic checklist for your device.
    Note: See the 7 Series Schematic Review Recommendations (XMP277), Kintex UltraScale and Virtex UltraScale FPGAs Schematic Review Checklist (XTP344), or UltraScale+ FPGAs and Zynq Ultrascale+ Devices Schematic Review Checklist (XTP427).
  7. Manually add XDC operating condition constraints to your XDC file for the Vivado tools. Use the XPE to generate a Xilinx design constraints (XDC) file, and import this file into the corresponding Vivado project. The XPE environment settings are translated to XDC constraints. The estimated total on-chip power becomes the design power budget for Vivado power analysis. For more information, see the Vivado Design Suite User Guide: Power Analysis and Optimization (UG907).