Technet, I am looking for general design guidelines on thermal vias. Can someone please let me know if there's any reference material available? My customer has question on ways to direct maximum heat away from the bottom side of SMT LEDs. The LEDs all have a 0.4" diameter base, flat on the bottom. The PCB currently has 0.4" round pads which we paste and solder the LEDs directly onto. Rgds, Peter --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------