> Try to make room for bypass caps on the back of the board from the FPGA.


You can use 0402 resistors with 0.6mm round pads on 1mm centres.

This allows thm to be placed on the back of the BGA 'matching' the
BGA pads, and allows almost one cap per power & gnd pair.

Check with your assembly house that they're happy with this, mine does it
no problem (they built a couple of boards with 0.5mm pads before telling
me to make them bigger).



Nial