The laminate will have an maximum operating temperature which is
different from Tg and Td.  Years back UL just tested materials to a 105C
maximum but newer materials have been tested at the 130C, which is the
case for most FR4's at "most" manufacturers.  

Jeffrey Bush
Director, Quality Assurance and Technical Support
VERMONT CIRCUITS INCORPORATED 
           76 Technology Drive - POB 1890 
              Brattleboro, Vermont 05302
                Voice - 802.257.4571 ext 37 
                    Fax - 802.257.0011
                       <http://www.vtcircuits.com/> 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Upton, Shawn
Sent: Friday, March 23, 2007 10:11 AM
To: [log in to unmask]
Subject: [TN] PCB Temp Guidelines

Had a recent question about using a PCB at 105C; I wasn't sure about it.
I usually spec FR4 for HASL finish, FR4 with Td_min=350C/CTE_max=3.5%
for immersion gold finish; and haven't done high temp (150C or more)
yet.  I figured, the board in question was RoHS compliant, so it
shouldn't outgas too quickly at 105C, at least not for brief testing --
but I wasn't sure about prolonged periods.

So, the question is, what is regular FR-4 recommended up to for
temperature?

Shawn Upton, KB1CKT
Test Engineer
Allegro MicroSystems, Inc
[log in to unmask]
603.626.2429/fax: 603.641.5336

---------------------------------------------------
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
-----------------------------------------------------

---------------------------------------------------
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
-----------------------------------------------------