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March 1999

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Subject:
From:
Cyrus Ringle <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 30 Mar 1999 13:19:22 -0700
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Regarding the definition of "heel" I have found a problem with J leaded PLCCs.

The IPC-SM-782 and IPC-A-610 definitions of heel for J leaded PLCC's do not
match.  In fact the IPC-SM-782 Section 12.1 page 3 and 4 contradict themselves.
You may have already run across this problem and I am assuming the correct
definition is page 3.  I make this assumption because it matches the IPC-A-610
spec 10.2.7 page 126.  Since there is a limitation to Email size I cannot attach
scanned in copies of the spec pages for your reference.  If you would like one
sent to you just send me an Email and I will forward it to you.



Cyrus Ringle
Sr. CAD Specialist at Inter-Tel ---- http://www.inter-tel.com
7300 West Boston Street
Chandler, AZ 85226
Email [log in to unmask]
Voice (602) 961-9000 x21216 or Direct 961-2263
Fax (602)961-1370

Vice President of the Greater Phoenix Designers Council ----  A part of the IPC
http://www.ipc.org/html/framesetdestypes.html
PO Box 3805
Scottsdale, AZ 85271




Phil Bavaro <[log in to unmask]> on 03/30/99 12:26:19 PM

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to
      Phil Bavaro <[log in to unmask]>

To:   [log in to unmask]
cc:    (bcc: Cyrus Ringle/Inter-Tel)
Subject:  Re: [TN] IPC Acceptance Criteria forGull Wing Leads




I came across an anomalie within the 610B document yesterday and need to
resolve it.  The criteria for the side joint length for a gull wing is what
is being questioned.

The spec states that the minimum side joint length is equal to "the heel
fillet" plus "the width of the lead".

My interpretation of this is as follows:

The assumption is that "the heel fillet" reference means the side view
length of the heel fillet as this length is never discussed in the section.
 It starts where the filletfeathers out to the pad and ends at the point
where the fillet joins the vertical section of the lead.

Now for the "the width of the lead":

A gull wing lead has a given lead width. I have two sizes of leads that
need to be addressed, the first where the lead to pad interface is
rectangular and the second where the interface is square shaped.

I'll further define this interface:
Rectangular: has a side length equal to twice the width
Square:  has a side length equal to the width

For the rectangular:  the minimum side joint length starts at the beginning
of  the heel fillet and ends halfway down the side of the side of the lead
(which equals the length of the lead width)

For the square:  the minimum side joint length starts at the beginning of
the heel fillet and ends at the toe of the lead.

All comments are welcome and appreciated.

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