Re: gEDA-user: Cheap 4 layer manufacturer?

[Darrell Harmon <mail@xxxxxxxxxxxx>]

On Mon, Oct 10, 2005 at 06:39:12AM -0400, Bob Paddock wrote:
> On Sunday 22 May 2005 03:52 pm, Darrell Harmon wrote:
> 
> > I will be using PCB Train (http://pcbtrain.com) for my next board since
> > the sierra proto express vias would not fit between the pads of a 1mm
> > pitch BGA.  They have also answered a few of my questions quickly.  They
> > seem willing to do arrays of boards.  I like this since I am working on
> > 3 different credit card sized boards and can save money by combining
> > them.  I will let the list know how this goes.
> 
> How did http://pcbtrain.com  work out for you?  I'm looking for someplace that 
> can do four layer boards, with out breaking my budget.

I started with the idea of using PCBtrain, and while the via size is
nice, the clearances they want on the inner copper is unusable. You
basically lose your entire ground plane under the BGA to vias.

There is a PDF file on my website of the layout I ended up with.
http://dlharmon.com/dspcard/dspcard-art.pdf

I use http://www.protoexpress.com currently. With the no touch service,
you get 2 of any 4 layer board under 8x10 inches for $137 shipped. I
bumped the ball size down from the Xilinx recomended 0.4mm to 0.34mm,
and everything worked out fine. I will be putting the ball size back
to 0.4mm and using smaller vias for production. I am getting prices
of about $500-800 for 100 boards with 10 mil vias and 6mil track/space.
The board is about the size of a credit card.

Let me know if you have any questions.

-- 
Darrell Harmon
http://dlharmon.com/dspcard
Credit card size DSP/FPGA board