TECHNET Archives

October 2010

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Condense Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Sender:
X-To:
TechNet E-Mail Forum <[log in to unmask]>
Date:
Thu, 21 Oct 2010 13:12:30 -0400
Reply-To:
Subject:
From:
Robert Kondner <[log in to unmask]>
Content-Transfer-Encoding:
7bit
Content-Type:
text/plain; charset="us-ascii"
Organization:
Index Designs
MIME-Version:
1.0
Parts/Attachments:
text/plain (48 lines)
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
-----------------------------------------------------

ATOM RSS1 RSS2