On 2/4/2010 1:41 PM, Nial Stewart wrote:
>> 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
>
I'll second that. It works for me. Make the pad size the limit of the
PCB fab's spec.

Cheers, Syms.