At 09:46 PM 3/12/2006, Dom Bragge wrote: > Does anyone know of a way to create off-center SMT pads in protel? > >The only way I can think of doing this is to have mutiple >overlapping pads or something similar. Not wonderful. I'd prefer to >have simply one pad per physical pin.
Pad center is not really relevant to SMT pads. It is a convenience (or nuisance) only, when pads don't have holes. It has a meaning with holes, i.e., the "pad center" is the hole center. For SMT, why would you want to create an "off-center" pad? You simply place the pads where you want! I've wished that pads could be defined by the edges, which is what is standard for SMT in spec. sheets. But it's not hard to appropriately position the pads, and there is always the wizard.... (which I haven't used in a long while....) Now, if you want a through hole or via in the pad, this is another story. One way is to simply put a via in the pad, where you want it. There is no particular reason for this to be at pad center. So, presto! you've created an "off-center pad." When one wants an off-center pad for through-hole components, Protel does not have a pad offset definition, and most of us have found we can live without it. If you want pad offset, the way to do it is to build out the pad in the desired direction with primitives that are part of the footprint, but not, I'd suggest, pads. Use, instead, track or fill on top or bottom layer. There is no reason that I have ever encountered to enlarge the inner layer pads to match an oversize or extended pad on the surface layers. So think of "pad" when there is a hole involved as the structure that extends through the board. Of course, you can also define different sizes by layer (the "padstack" option). All of them, though, will be centered on the hole. ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
