Bob, I wouldn't be worried about the FR-4. They can cope with +200 C for short periods. I would rather be worried for the IC's. If they heat the board to more than one hundred centigrades, what then about the chip temperature? Chips withstands +150 C or more, but most use to derate them to a temperature for a long life. Why not use a multilayer ceramic board if you need a high temperature application? Inge ----- Original Message ----- From: "Robert Kondner" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, October 21, 2010 7:12 PM Subject: [TN] FR4 Temperature and Life > Hi, > > > > I was looking around and I found some references to "FR4" as having a Tg > from 100 to 130 C. I was surprised as I thought that seemed low. > > > > Now I understand that FR4 is a pretty wide brush and it covers a lot of > different materials and different suppliers. BUT, I was wondering what > "Most" PCB vendors are supplying and how the Tg affect life with hot > components. > > > > I have some small QFN parts that tend to run hot, PCB temps of 100C or a > little more. Forgetting thermal cycling for a moment does a 100 to 120 C > temperature induce failures in other area like copper foil to base > separation, de-lamination, solder interface or any other failure mode? > > > > Any pointers to literature? > > > > Thanks, > > Bob K. > > > > ______________________________________________________________________ > This email has been scanned by the MessageLabs Email Security System. > For more information please contact helpdesk at x2960 or [log in to unmask] > ______________________________________________________________________ > > --------------------------------------------------- > 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 > ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- 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 -----------------------------------------------------