PCB Libraries Forum : Under-body outward L-lead courtyard calculation https://www.PCBLibraries.com/forum/ Tue, 21 Jul 2026 09:37:33 +0000 Tue, 21 Jul 2026 08:25:48 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 30 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=3663 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[Under-body outward L-lead courtyard calculation : All component packages taller...]]> https://www.PCBLibraries.com/forum/underbody-outward-llead-courtyard-calculation_topic3663_post14595.html#14595 Author: Tom H
Subject: 3663
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'.

]]> Tue, 21 Jul 2026 08:25:48 +0000 https://www.PCBLibraries.com/forum/underbody-outward-llead-courtyard-calculation_topic3663_post14595.html#14595 <![CDATA[Under-body outward L-lead courtyard calculation : Hello,Yesterday I was approaced...]]> https://www.PCBLibraries.com/forum/underbody-outward-llead-courtyard-calculation_topic3663_post14594.html#14594 Author: felecro
Subject: 3663
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. 
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