Yes on the package size; no on th lead count.
The parameters for different package sizes are covered in both the MSD
Classification Test Method IPC/JEDEC J-STD-020C and in the associiated
packaging, labeling and handling document IPC/JEDEC J-STD-033A.
Jack
Jack Crawford, IOM
IPC Director Certification and Assembly Technology
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Genny Gibbard
Sent: Friday, October 08, 2004 1:20 PM
To: [log in to unmask]
Subject: [TN] Moisture sensitivity
Just a question for interest sake. Are there any general correlations
between package size, and lead numbers, and moisture sensitivity that
can be made?
For instance, do you think a 17.5mm square 44 lead 4.5mm thick package
would have less or more moisture sensitivity than a 16mm square 64 lead
1 mm thick package. The IC's have different functions.
Gut feeling, I think the 64 lead would have more sensitivity. It is
smaller, with more and finer pitch outside connections. As dimensions
get smaller, I think the danger of moisture doing damage goes up. Also,
since there are more leads I feel that there are more locations that
possibly moisture could get in, as the potential for seal breaks is
probably greater at interfaces between plastic and metal?
Am I out to lunch in my general reasoning?
Just thought I would spice up Friday.
To all those Canadians out there, enjoy your turkey and pumpkin pie this
weekend.
Genny Gibbard (mailto:[log in to unmask])
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