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AR# 65357

GT signal routing with non-ideal ground returns


I am unable to provide 2 reference Ground planes in a Printed Circuit Board (PCB) for GT signal routing.

Is there any issue with one of them being a Power plane and the other a Ground plane.


If the reference plane copper is solid and it is connected to Power or Ground, it should not matter for most cases.

For GT signals, One Ground Plane and one Power Plane as the reference is fine, provided the below factors are taken care of:

  1. Impedance Continuity [No Copper Voids, proximity of antipads].
  2. Reference Plane Integrity [No holes under the trace, no voids].
  3. If possible, referencing them to the power plane that drives the signal is preferred.
  4. No routing GT signals over split planes.
  5. Maintain a low impedance between the Power plane and Ground.
  6. Double check for crosstalk risk in the vertical direction.

AR# 65357
Date Created 09/08/2015
Last Updated 10/27/2015
Status Active
Type General Article
  • Virtex-7