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3.3V Decoupling



Section 4.4.2.1 of the PCI Spec Revision 2.1 states:

  Additionally, all +3.3V pins (even if they are not actually 
  delivering  power) . . . on the PCI edge connector provide 
  an AC return path, and must have plated edge fingers and be 
  coupled to the ground plane on the add-in board . . . to 
  ensure that they continue to function as efficient AC 
  reference points . . ."

Can someone explain why the specification does not allow 
unplated fingers? Would a board with unplated +3.3V fingers
have significantly different characteristics than an 
unpopulated PCI slot?
*********************
*    Jerry Sabath   *
*  (508) 658-5600   *
*  sabath@agfa.com  *
*********************
5,