Vince Harlan asked: > I have a 12 layer PWB(Backplane) with 8 ground planes(all 2 oz.). > Each connector on this assembly has several pins that connect to > all 8 ground planes. Each connection is thermally relieved by 4 > separate .010" traces(spoked). Each trace is .035" in length. > The connectors that are on the top layer have been successfully > flowsoldered, ... > Does anyone have experience with this type of design and/or are > there any guidelines that might help me in reevaluating this Most interesting... These values are roughly 4x the maximums for IPC-D-275 on thermal reliefs. On *several* occaisions I've been faced with higher current levels than the IPC std would per- mit, and have needed to specify hand soldering since I could not get reassurance (on technet or otherwise) that reliable machine soldering was possible. Perhaps it's the .035" long hookup that helps? Perhaps it's also time to look at IPC-D-275's thermal relief spec- ification. Can anyone comment on the origins of that spec? Best regards, Jeff Seeger Applied CAD Knowledge Inc Chief Technical Officer Tyngsboro, MA 01879 [log in to unmask] 508 649 9800 *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************