Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

previous by date index next by date
previous in topic topic list next in topic

Subject: RE: [Homebrew_PCBs] Layout considerations - BIG PADS!

From: "Pedro Perez de Ayala Rull" <payala@...>
Date: 2003-12-30

Yes, I totally agree with you. This board had to be aligned with very
special care for that reason, the small via size was an error(I learned that
in the drilling phase...). I think it is a valuable advice to keep in mind.

Pedro

-----Mensaje original-----
De: Stefan Trethan [mailto:stefan_trethan@...]
Enviado el: lunes, 29 de diciembre de 2003 13:03
Para: homebrew_pcbs@yahoogroups.com
Asunto: [Homebrew_PCBs] Layout considerations - BIG PADS!


Hi all.

I just want to throw in (again) the following:

If you make boards with no through hole plating YOU NEED BIGGER PADS.
The layout software standard pads are for plated holes, where the pad can't
lift off
that easy.

I made that mistake in the past too, since i enlarged my pads
the quality of the pcbs is much better.

The photos of Pedro reminded me of that.
(Great quality of TT Pedro but it would look much better with larger pads
that don't lift off.
My TT is still a bit less quality, i hope i get it up to your standards.)


The function of the pad is not only for electrical contact, but also
mechanical mounting
of that component. Keep that in mind.
A big pad also allows for some offset with two layer boards.

I use mostly oblong pads. they still allow 1 or 2 tracks between DIL ic
pins. But they are long enough to provide some support.

There is this saying amongst pilots, "nothin' more useless to a pilot than
air above
you an' runway behind you" (or similar).
For a pcb designer nothing is more useless than free pcb space beside a
lift-off pad rim.


As said, the larger pads were a great improvement for me - therefore i want
to share the thought.
Please don't mistake it as an offence to any of your designs.

Stefan








Be sure to visit the group home and check for new Bookmarks and files:
http://groups.yahoo.com/group/Homebrew_PCBs

Yahoo! Groups Links

To visit your group on the web, go to:
http://groups.yahoo.com/group/Homebrew_PCBs/

To unsubscribe from this group, send an email to:
Homebrew_PCBs-unsubscribe@yahoogroups.com

Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/