Re: Designing for and soldering a tiny BGA

On Apr 11, 11:36 am, zwsdot...@xxxxxxxxx wrote:
On Apr 11, 2:07 pm, rickman <gnu...@xxxxxxxxx> wrote:

I would strongly suggest that you not use eagle and instead use
FreePCB.  Eagle is not really freeware and you can get into problems

Nothing is truly free. EAGLE is a mature commercial package with good
peer and vendor support (even for the free edition). Ceteris paribus,
it is a much better choice than FreePCB for this reason alone. And of
course there is no problem creating a footprint for a BGA - simply set
the grid size to the pad spacing, click the left mousebutton 81 times,
and you're done. It's a matter of a few minutes to draw the footprint
for a 9x9 device. If you look in Cadsoft's download areas you'll
probably find some BGA libraries I drew up (StrongARM devices, I think
- it's been a long time).

However the point is moot; the free edition of EAGLE is limited to two
signal layers and that really isn't enough for this application. It is
difficult and IMHO very ill-advised to attempt fanout of a dense-pitch
MBGA without at least four layers. I know it's possible to do it in 2,
but it's not ideal.

If you need most of the pads, 2 is impossible. With filled-vias
(center of BGA pads) and/or blinds, 4 would be possible. Otherwise, I
would suggest 6 to 8.
.

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