Re: gEDA-user: six-layer stack

[Larry Doolittle <ldoolitt@xxxxxxxxxxxxxxx>]

Friends -

On Wed, Feb 01, 2006 at 11:20:38AM -0800, Larry Doolittle wrote:
> > If you're doing high speed stuff, it pays to subscribe to
> > [SI-list] list.
> 
> Well, lurk through its archives anyway.

http://www.freelists.org/archives/si-list/

The topic of 6-layer stackups is covered in the thread starting
http://www.freelists.org/archives/si-list/04-2005/msg00204.html
The expert conclusion (from Steve Weir) is
http://www.freelists.org/archives/si-list/04-2005/msg00275.html
http://www.freelists.org/archives/si-list/04-2005/msg00324.html
that my original stack makes perfect electrical sense.
They discuss layer thicknesses of 3.2+4+38+4+3.2, similar to but
even more aggressive than my original suggestion of 5+5+30+5+5.
Discussion of board warpage and workarounds is included.
Maybe I should email Graham Davies and ask what fab house he uses.

Just because it's electrically "Right", doesn't mean it's properly
engineered.  If 4+14+4+14+4 is cheaper and more available, I can
use that.  I just have to know and adapt before I can call my
layout finished.

I guess this has always been only marginally on-topic in geda-users.
It would be nice to work with fab shops that are supportive of
gEDA/pcb, like Advanced Circuits, if possible.  I look forward
to seeing DJ's complete list, and we can start filling in the column
"has correctly fabbed a board from pcb snapshot _____".

     - Larry