Carl and Mike,
Far as I know, 130 C is the highest continuous operating temperature rating
that UL will give any FR4 material.

Regards,
Mark


        -----Original Message-----
        From:   Mcmaster, Michael [SMTP:[log in to unmask]]
        Sent:   Wednesday, May 14, 2003 2:30 PM
        To:     [log in to unmask]
        Subject:        Re: [TN] Hot Boards!

        Carl

        You got the 120C number from Table 4-1 in IPC-2222, right?  What's
the minimum dielectric thickness in the board?  It's also important to note
that this chart just lists FR4 and doesn't have a separate listing for
Higher Tg materials.   I think this is why they include footnote 6 "Other
materials in the same classification with higher operating temperatures may
be available."  You want to avoid low Tg FR4 materials since you'll be very
close to that transition point.  The best thing to do is find out from the
laminate manufacturer what the maximum continuous operating temperature for
their material is.  This information is not usually on the standard data
sheets but it is available.

        One other thing you need to watch out for is to make sure you're
fabricator has UL recognition for high enough Maximum Operating Temperature
(MOT) for the materials used in this board.  It's not enough to ask for
flammability.  You also need to specify a specific MOT if you want it and
you probably want at least 130C for this board.

        Mike McMaster
        RF Product Engineer
        Merix Corporation
        503-992-4263


---------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------