QFN Pad Calculation Problem
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=2294
Printed Date: 25 Nov 2025 at 6:32pm
Topic: QFN Pad Calculation Problem
Posted By: robmeyer
Subject: QFN Pad Calculation Problem
Date Posted: 08 Feb 2018 at 4:58am
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Hi, when I try to generate a QFN with Version 2018.02 the Pads are to small, see picture. I also add the fpx to this post. uploads/870/QFN_error.fpx" rel="nofollow - uploads/870/QFN_error.fpx When I make D2 shorter (0.8mm) then the footprint looks good. Looks like the calculation takes the removed Pins also in it or something else is wrong.  |
Replies:
Posted By: Tom H
Date Posted: 08 Feb 2018 at 9:53am
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The problem here is that you are using the QFN (Quad Flat No-Lead) component family to create a SON w/Tab (Small Outline No-Lead) footprint. Try using the SON with Tab and you'll get perfect results. There is no bugs or issues with V2018 Library Expert. ------------- Stay connected - follow us! https://twitter.com/PCBLibraries" rel="nofollow - X - http://www.linkedin.com/company/pcb-libraries-inc-/" rel="nofollow - LinkedIn |