Sender: |
|
X-To: |
|
Date: |
Thu, 21 Oct 2010 13:12:30 -0400 |
Reply-To: |
|
Subject: |
|
From: |
|
Content-Transfer-Encoding: |
7bit |
Content-Type: |
text/plain; charset="us-ascii" |
Organization: |
Index Designs |
MIME-Version: |
1.0 |
Parts/Attachments: |
|
|
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
-----------------------------------------------------
|
|
|