When it comes to troubleshooting a fine pitch multi (>100) pin chip - I
silently thank the layout Engineers for putting a rectangle pad every
10th pad.....
Steve Gregory wrote:
>
> 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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