Steve, I use Orcad Layout quite regularly as well and the situation you're descibing is a 'regular feature' in Orcad. A good majority of the SMD footprints in their libraries have this alternating oblong/rectangular pad pattern. Mostly, as the others have mentioned, for troubleshooting but also for artwork inspection/net checking. Many of their QFPs and SOICs use this pattern. On most fine-pitched devices you'd never be able to tell the difference after soldering (unless you magnify). I generally change all the pad shapes to oblong -and generally before loading them into the design. It's not that much work to accomplish after the fact but is definitely a pain -you'd have to scan thru the padstack spreadsheet for that decal and replace each rect. pad reference with an oblong ref. for both horizontal and vertical pads - not as easy as modifying a gerber dcode (which you should always avoid anyway). There is a chance though that similar devices may use different decals in which case each one would have to be examined and modified -this may be what the designer was referring to as 'too much trouble'. The only problem I can see with the rect type pads is it may make routing a little more dense. From what I've read on the use of rounded corner or oval/oblong pads, is that they help in centering (to a small degree) the IC onto the pattern during reflow. If it's a production run it might be worth the trouble to change them but if prototype could be left as is. Ron O. Mindlink Technologies At 02:53 PM 6/21/02 -0400, you 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- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------