Sheesh, you try to help one person, and some one else complains. A square
pin is usually pin 1 on thru-hole ICs, and for surface mount it is
rectangular, with the other pads oval or rounded. Making every 10th pin
square or rectangular aids in troubleshooting, since the tech will have an
easier time counting pins.
This is the first time I've heard this possibly could be a problem. I would
be more worried on how to assemble those caps between the ICs and next to
the BGA!
David Ricketts
Pertek Engineering
Voice: 949-475-4485
Fax: 949-475-4493
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Steve Gregory
Sent: Friday, June 21, 2002 11:54 AM
To: [log in to unmask]
Subject: [TN] PCB lay-out problem...
Hi all,
We're having a board lay-out done outside, and as with new designs, I will
get asked to look at the preliminary gerbers to see if I can see anything
out of place that might need changing.
I looked the the gerbers that were given to me and the first think I noticed
was that on some IC footprints, there was 1 rectangular pad, then 9 pads
where the corners were rounded, then a rectangular pad, and on and on...
So I fed that back to our engineer here who is over this project, then he
fed that back to the individual who is doing the lay-out. Our engineer here
then came back to me and asked if that would be a problem, and I told him it
could be, but why not make all the pads uniform? Go to:
http://www.stevezeva.homestead.com and look at "OrCad" to see what I mean.
His reply was that the individual doing the layout told him he would have to
go in and manually edit each one of the pads that were rectangular, and that
it would be too much trouble. He said this is the way OrCad put the
footprint down, and if it was such a problem, why would OrCad have this
footprint in the library? Then he added that the IPC-SM-782 says that you
can either use rectangular pads or optionally round the corners, so that
tells him you can use either one or both, and it doesn't make any
difference. So he told the layout person to leave things as they are.
I don't know anything at all about OrCad, but something tells me there's an
operator problem here. I've never seen a footprint like this before, and no
matter what I say, I can't convince our engineer here that the footprint
needs to be fixed.
HELP!!! PLEASE!!!
Thanks,
-Steve Gregory-
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