PCB Libraries Forum : PTH Minimum Annular Ring https://www.PCBLibraries.com/forum/ Mon, 06 Apr 2026 17:21:30 +0000 Tue, 09 Sep 2025 08:42:54 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=3531 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[PTH Minimum Annular Ring : The Hole Diameter for round PTH...]]> https://www.PCBLibraries.com/forum/pth-minimum-annular-ring_topic3531_post13993.html#13993 Author: Tom H
Subject: 3531
Posted: 09 Sep 2025 at 8:42am

The Hole Diameter for round PTH terminal leads is Max Lead Diameter X 0.20 mm. 

The Hole Diameter for rectangle PTH terminal leads is Max Lead Diameter X 0.15 mm. 

The default pad diameter is 1.5 times the Hole diameter but you can adjust all these values. 

The annular is proportional. 

A 1.00 mm hole = 1.50 mm pad = 0.25 mm annular ring.

A 2.00 mm hole = 3.00 mm pad = 0.50 mm annular ring. 

A 3.00 mm hole = 4.50 mm pad = 0.75 mm annular ring. 

The Minimum Annular Ring of 0.40 is very robust for tiny PTH packages with fine wire terminal leads (like watch crystals). The pad size would be excessive. 

Minimum is intended for the smallest terminal lead and hole like a Tuning Fork Crystal. 

https://cfd.citizen.co.jp/cms/cfd/pdf/english/CFS-206_CFS-145_E.pdf

the terminal lead diameter is 0.20 mm and the hole size would be 0.40 mm diameter. A 0.40 minimum annular ring would be a 1.20 mm pad diameter. 

The pin pitch is only 0.45 mm. 

This is an example where a 0.40 mm minimum annular ring would be too robust. Too much solder for a tiny hole. 

]]> Tue, 09 Sep 2025 08:42:54 +0000 https://www.PCBLibraries.com/forum/pth-minimum-annular-ring_topic3531_post13993.html#13993 <![CDATA[PTH Minimum Annular Ring : Minimum annular ring is defined...]]> https://www.PCBLibraries.com/forum/pth-minimum-annular-ring_topic3531_post13992.html#13992 Author: m.elsayed
Subject: 3531
Posted: 09 Sep 2025 at 5:00am

Minimum annular ring is defined in the Options > Terminals > Through-hole
 
When set to 0.40 mm, does it mean no value than this will be create for any part?
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