Re: gEDA-user: problem

[sdb@xxxxxxxxxx (Stuart Brorson)]

One other point about buried & blind vias:  Most garden-variety PCB
fab houses can't do them.  Check with your PCB vendor & verify they
have that capability before you get deep into a design using them.

Stuart


> not quite! but we are looking into 6 layer boards for PC applications, ru=
> nning at a few hundred MHz.
>  I am worried about signal reflections from such large height vias.
>  Thanks
>  Amr
> 
> Stuart Brorson <sdb@xxxxxxxxxx> wrote: Ummm, are you sure you need to use=
>  buried vias?  Most PCB fab houses
> don't support them; they are used on super-dense, high-tech boards,
> and you pay mucho extra $$$ to get them.  They are not used on
> entry-level to mid-level boards. =20
> 
> If you *are* using PCB to design a 20 layer OC-192 router board with
> 10Gig diff co-planar waveguides and 622Mbps parallel busses, then
> bully for you!  Let us know how it goes!=20
> 
> Stuart
> 
> 
> > Hello
> > Is there a work-around to the absence of buried vias? for example,=3D20
> > edit the drill file to remove a specific thru-hole, and copy this=3D20
> > via into the file for layer 2-3?
> > Best Regards
> > Amr Bayoumi