Bill,
This device looks as though it is plastic and probably some form of
laminate material. So I would imagine that the CTE deltas are much closer
together than FR4 and ceramic. It is only between FR4 and ceramics that I have
ever heard of CTE problems with leadless/leadframe devices.
Is that bottom view actually showing a large central soldered pad? If
so I would also think that you should have no CTE problems as the large pad
would help to stabilize the device and reduce the overall delta
expansion/contractions and the related stresses on the individual solder joints.
Sincerely,
Brad Velander
Senior PCB Designer
Northern Airborne Technology
#14 - 1925 Kirschner Road,
Kelowna, BC, V1Y 4N7.
tel (250) 763-2329 ext. 225
fax (250) 762-3374
-----Original Message-----
From: Brooks,Bill [mailto:[EMAIL PROTECTED]
Sent: Thursday, December 01, 2005 12:31 PM
To: 'Protel EDA Discussion List'
Subject: [PEDA] Footprint needed
I have a Analog devices part, 56-lead Lead Frame Chip Scale Package LFCSP
with an 8X8 mm body CP-56 supposed to be compliant with JEDEC MO-220-VLLD-2.
Having a tough time locating a recommended footprint for this one...
Any help?
Also any issues with mounting? Since this is a direct to board soldered
device, it may be subject to CTE mismatches and the like... anyone have
experience with this part?
Here's a link to the part description.
http://www.analog.com/UploadedFiles/Packages/352655155839944545242119821CP_5
6.pdf
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
Datron World Communications, Inc.
_______________________________________
San Diego Chapter of the IPC Designers Council
Communications Officer, Web Manager
http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
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