You should look up the spec of the specific device you are using. A generic spec or national standard is no good. We have just had a similar problem with a part and the data sheet only qualified the part for a minimum of 50% of the thermal pad soldered. (And that was not the first time we've had that constraint) Looking at your X-Ray there were lots of 'thermal' vias and therefore it appeared that the designer was very concerned about getting heat out. Having only 33% coverage seemed low where so much attention had been given to thermal vias. Regards Rex Rex Waygood Technical Manager PartnerTech Poole Ltd Benson Road Poole Dorset BH17 0RY United Kingdom Tel: +44 (0)1202 674333 Fax: +44 (0)1202 678028 DDI: +44 (0)1202 338222 Mob: +44 (0)7887 997403 [log in to unmask] www.PartnerTech.co.uk -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez Sent: 22 July 2008 13:04 To: [log in to unmask] Subject: Re: [TN] Thermal header Solder attachment Guidelines Rex & other contributors, You state " Many of these devices recommend a minimum of 50%. To me that would be a more serious problem." Where can I find related articles and industry standard for this statement. Victor, ----------------------------------------------------- ------------------------------------------------------------------------------- The information contained within this e-mail and any attachments contained therein may be confidential and/or legally privileged and is for the use of the intended recipient only. If you are not the intended recipient please delete it from your system and notify the sender by return e-mail. The content of this e-mail may not be copied or disclosed to any third parties without prior permission from the sender. E-mail is susceptible to data corruption, interception, tampering and viruses. We do not accept any liability for any such incidents or any consequences thereof. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 -----------------------------------------------------