Earl,
Not sure what went on last year. We us a pad with full radius ends for our
0603 and 0402 components. The rounded ends seem to pull the solder
perpendicular to the length of the component, very few 'tombstones' almost
no reports of end cap cracking, not bad for a million + boards a month.
What is our pad formula? If you design a 'standard rectangular pad' and
round the 'width' of the pad on both ends you have it.

Jerry Galang
Xircom, Inc.

-----Original Message-----
From: Earl Moon [mailto:[log in to unmask]]
Sent: Tuesday, February 06, 2001 2:20 PM
To: [log in to unmask]
Subject: [TN] Chip device vs pad sizes

I'm still down sizing pads to mount/solder chip devices. We had a
conversation about mounting 0603's on 0402 pad configurations last year. I'm
still going with that with some modifications. Anyone have anything else to
contribute concerning increased reliability as fewer end cap cracking
problems and solder joint failures? It all goes back to the early '80's as
LCCC's and related stuff with TCE mismatch problems.

Earl Moon

Proof Of Design

----------------------------------------------------------------------------
-----
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send the following message: SET
Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail 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
----------------------------------------------------------------------------
-----

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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
---------------------------------------------------------------------------------