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| Date: | Tue, 13 Jul 2010 16:07:31 -0400 |
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Hi Brad,
When you say 'radius lands'—what exactly do you mean? Can you share your experiences?
Werner
-----Original Message-----
From: Brad Saunders <[log in to unmask]>
To: [log in to unmask]
Sent: Tue, Jul 13, 2010 3:58 pm
Subject: Re: [TN] 0201 footprint requirements
Howdy Bill,
I was delighted to see Werner's answer on this question. I had done very
exhaustive reliability study on solder joint reliability specifically related to
footprint design and we concluded exactly what Werner was able to say so
eloquently. I found later the footprint also was a political platform and to
satisfy a consensus I constructed a formula that would give a bit of pad to the
sides and ends. I knew it would not subtract from reliability and -so long as
it didn't get to big I was OK- it did allow me to round off pad sizes which is
very nice, also I was able to manipulate center spacing which additional
benefits.
But don't grow that length under your parts... and don't get me going on radius
lands verses square.
Boston Brad
----- Original Message -----
From: Brooks, Bill<mailto:[log in to unmask]>
To: [log in to unmask]<mailto:[log in to unmask]>
Sent: Wednesday, July 07, 2010 2:37 PM
Subject: [TN] 0201 footprint requirements
I am looking for some assistance with the pad geometries for 0201 caps
and resistors...
Is there or is there not an industry consensus on what the optimum pad
geometry should be for them?
What I am hearing from our assembly houses differs greatly from what is
published in IPC-7351 and the land pattern tool from PCB Matrix.
Is the max material condition footprint actually a recipe for
tombstoning?
What have you folks seen? What do you recommend?
Bill Brooks | Datron World Communications, Inc.
PCB Designer/Engineer | Office: 760-602-7004| Fax: 760-597-3777 |
[log in to unmask]<mailto:[log in to unmask]>
1808 Aston Avenue, Suite 230, Carlsbad, CA 92008 | www.dtwc.com<http://www.dtwc.com/>
Performance You Require. Value You ExpectTM
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