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32L PLCC Dimension D2 Query

Printed From: PCB Libraries Forum
Category: PCB Footprint Expert
Forum Name: Questions & Answers
Forum Description: issues and technical support
URL: https://www.PCBLibraries.com/forum/forum_posts.asp?TID=1336
Printed Date: 07 Oct 2024 at 7:53pm


Topic: 32L PLCC Dimension D2 Query
Posted By: jameshead
Subject: 32L PLCC Dimension D2 Query
Date Posted: 12 May 2014 at 7:42am
Using 2014.02 to create a Winbond 32L PLCC, datasheet here:

http://www.winbond.com/NR/rdonlyres/A0AC3708-50FF-4854-853A-92DC4CB01B37/0/W39L040A.pdf" rel="nofollow - http://www.winbond.com/NR/rdonlyres/A0AC3708-50FF-4854-853A-92DC4CB01B37/0/W39L040A.pdf

The Surface Mount calculator has a D2 dimension but it's a bit unclear what this dimension is meant to be in the screen picture, other than it being a required entry.

I wondered if it was meant to be the dimension GE that's shown on the Winbond datasheet?

If so, there's no corrisponding E2 in the opposite plane to be equivilent to GD in Library Expert.


Replies:
Posted By: Tom H
Date Posted: 12 May 2014 at 7:52pm
D2 is the dimension from the center of the J-Lead to the center of the J-Lead.

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Posted By: jameshead
Date Posted: 13 May 2014 at 12:42am
Thanks Tom, that's what I'd thought but on screen it's a bit difficult to make out, even on a 24 inch monitor!

This particular PLCC though has a different number of pins along one side then the other, so I would expect to have an E2 as well as a D2 dimension to be entered.

In this case D2 is GE on the datasheet, being 10.41 mm nominal.

What's missing in Library Expert is an E2 to match up with GD on the datasheet, being 12.95 nominal, or are you taking care of that internally in the software?

I guess you could work out E2 by knowing D2, D1 and D, and then knowing E and E1, and workout what E2 could be?

Posted By: Tom H
Date Posted: 13 May 2014 at 5:37am

You mention that the dimensional picture is too small to make out the details.

Did you know that you can click & drag and stretch the windows to make the picture super big or small.  




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Posted By: jameshead
Date Posted: 13 May 2014 at 5:43am
yes, but this dim didn't look obvious to me at first so I was checking particulary because of the absence of an "E2" dimension.


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