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July 2003

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Subject:
From:
Mike Fenner <[log in to unmask]>
Reply To:
Date:
Thu, 31 Jul 2003 08:46:59 +0100
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I took your question to mean "what is the total pad size relative to the
weight of a device to retain it during double sided reflow without
adhesive?" If that is not what you mean then I think you need to enlarge
your question.

Regards

Mike

ps OK now Brian?


-----Original Message-----
From: Walters, Karen [mailto:[log in to unmask]]
Sent: Wednesday, July 30, 2003 4:35 PM
To: [log in to unmask]
Subject: RE: [TN]


Isn't this when you need to apply epoxy to hold down the unit.  Is there a
possibility that we have too much or to little pad spacing causing the unit
to float.

Please advise?  Thank you so much for your input.
-----Original Message-----
From: Mike Fenner [mailto:[log in to unmask]]
Sent: Wednesday, July 30, 2003 11:33 AM
To: [log in to unmask]
Subject: Re: [TN]


This comes up reasonably often and the answer is in the archive therefore.
I don't think there is a spec, two numbers are quoted
Zarro: 30 gm/ sq in
Willis: 44gm/sq in
Interesting that both mix their units:)

Regards
Mike Fenner
Indium Corporation of Europe
T: + 44 1908 580 400
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Charles Caswell
Sent: Wednesday, July 30, 2003 3:28 PM
To: [log in to unmask]
Subject: Re: [TN]


Idon't know of a spec. for pad size relative to weight.  Pad sizes are
generally determined by  by component footprint. Maybe somebody with SM-275
or SM-782 can help.
-----Original Message-----
From: Walters, Karen [mailto:[log in to unmask]]
Sent: Wednesday, July 30, 2003 8:17 AM
To: [log in to unmask]
Subject: [TN]



Can anyone reference for me the the IPC SPEC that states what the pad
surface area requirement is to the weight of the packaged device.  We may be
having an issue with a floating component during reflow.  Please also
provide the ratio if anyone knows it off hand.

thanks

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