The joys of SI tuning: I'm staring here at this sea of diffpairs that I need to get optimized before I order the board.
But if I jump too fast and start making changes before I'm done tweaking I might have to rip up and reroute 16 transceiver lanes *again* lol
Changes that need to be made so far:
* Replace elongated 0.5mm rounded-rectangle cutouts under top layer BGA lands with 0.45mm circular cutouts under each land individually
* Don't do linear fanouts with meanders outside the ball field to correct, fan out as a pair to the east or west then make a turn south
* Add power/ground plane void around vias under ARC6 connector on layers 4, 5, and 6 in addition to the existing layer 2 void
* Make fanout traces coming off the ARC6 fatter until they join together
* Adjust length tuning to make traces phase matched along their entire length not just end to end
Andrew Zonenberg