We use tons of Dpaks as mentioned here, The large heatsink stencil aperture
is reduced 2/3 from the land and windowpaned into 4 to 10 smaller apertures
with window frame thickness of 0.5mm.  This prevents Dpak floating and
moving during reflow and ensures a good solder joint fillet at the solder
termination end.  Dpak will move if you use the same stencil aperture as the
land.

Matthew S. Park
Sr. Process Engineer
Phoenix International Inc.  Fargo, ND.
Tel: 701-282-9364, ext 434
Fax: 701-282-9365



-----Original Message-----
From: McMonagle, Mike [ mailto:[log in to unmask] <mailto:[log in to unmask]> ]
Sent: Friday, October 13, 2000 11:28 AM
To: [log in to unmask]
Subject: Re: [TN] paste area for case on a to 263 5 lead part


Leo,
    You might want to 'window' it into 4 squares, with an .030 web in
between the squares. Leave the overall outer footprint the same as the outer
footprint of the pad to ensure good wetting around the perimeter of the
device tab. With just one large open area or two rectangles, even a metal
blade will have a tendency to scoop out paste from such a large aperture.
Even with an .030 or larger web between the 'window panes', you should have
no problem with achieving adequate paste volume for the device tab.

Mike McMonagle
Senior SMT Engineer
Telxon Corporation
www.telxon.com <http://www.telxon.com>  < http://www.telxon.com
<http://www.telxon.com> >





-----Original Message-----
From: Flick, Leo [ mailto:[log in to unmask]
<mailto:[log in to unmask]> ]
Sent: Friday, October 13, 2000 10:40 AM
To: [log in to unmask]
Subject: [TN] paste area for case on a to 263 5 lead part





hi

our production is questioning the size of the land for solder paste for a
to263 5 lead part. they fear that there will be too much paste in that area.
the pad for the case is .410 x .425 and we specified the same size clearance
for the solder paste. their suggestion is to use two smaller rectangles
instead of one large square surface.

any suggestions or comments ?
thank you

Leo Flick or Dave Kissinger
DRS Communications Company
1200 E.  Mermaid Lane, Wyndmoor, PA 19038
[log in to unmask] < mailto:[log in to unmask]
<mailto:[log in to unmask]> >
[log in to unmask] < mailto:[log in to unmask]
<mailto:[log in to unmask]> >

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