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Under-body outward L-lead courtyard calculation

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=3663
Printed Date: 21 Jul 2026 at 6:15pm


Topic: Under-body outward L-lead courtyard calculation
Posted By: felecro
Subject: Under-body outward L-lead courtyard calculation
Date Posted: 20 Jul 2026 at 11:19pm
Hello, 

Yesterday I was approaced by one of our designers who has an issue with a new aluminium capacitor we added to the Altium component database. He wanted to use the new capacitor as a replacement for another that was added to the DB a few years ago. He expected them to be interchangable because they have same dimensions, but he encountered an issue with clearance between components. 

As it turns out, the new capacitor has bigger courtyard and the reason for this is different courtyard calculation setting in the newever versions of FP Expert. From what I can see, the 2026 and 2025 version both have it under  "Under-body Outward L Lead" settings. If the component height is greater than 10mm, the nominal density courtyard expansion is 0.4mm. If it's below 10mm, the standard 0.2mm is used.  

I was wondering what was the motivation for this change and when did it happen? I tried search the forum for this topic but couldn't find anything about it. 


Replies:
Posted By: Tom H
Date Posted: 21 Jul 2026 at 8:25am
All component packages taller than 10 mm get a larger courtyard excess per IPC-7351B Table 3-20. This is to make rework easier for failed components. You need to get extraction equipment (like heat nozzles) to unsolder the leads and remove the nonfunctional component and replace a new one. 

However, if there are no plans on reworking failed packages, then change the courtyard excess to 0.20 or whatever value is your default setting in 'Tools > Options > Terminals > Under-body Outward L Lead > Courtyard'.



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