PCB Libraries Forum : Library expert PTH calculator https://www.PCBLibraries.com/forum/ Sun, 05 Apr 2026 14:42:41 +0000 Tue, 14 Mar 2017 13:13:04 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=2114 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[Library expert PTH calculator : Library Expert does auto-generate...]]> https://www.PCBLibraries.com/forum/library-expert-pth-calculator_topic2114_post8749.html#8749 Author: Tom H
Subject: 2114
Posted: 14 Mar 2017 at 1:13pm

Library Expert does auto-generate IPC-7351 pad stack names.

And you can manually change the hole, pad, mask sizes and Library Expert will auto-update the pad stack name to the new values.

]]> Tue, 14 Mar 2017 13:13:04 +0000 https://www.PCBLibraries.com/forum/library-expert-pth-calculator_topic2114_post8749.html#8749 <![CDATA[Library expert PTH calculator : OK thanks TomWhat about the nice...]]> https://www.PCBLibraries.com/forum/library-expert-pth-calculator_topic2114_post8748.html#8748 Author: nw002
Subject: 2114
Posted: 14 Mar 2017 at 12:22pm

OK thanks Tom

What about the nice feature that it automatically gave you the padstack name?

regards

]]> Tue, 14 Mar 2017 12:22:00 +0000 https://www.PCBLibraries.com/forum/library-expert-pth-calculator_topic2114_post8748.html#8748 <![CDATA[Library expert PTH calculator : IPC never released the Through-hole...]]> https://www.PCBLibraries.com/forum/library-expert-pth-calculator_topic2114_post8747.html#8747 Author: Tom H
Subject: 2114
Posted: 14 Mar 2017 at 12:03pm

IPC never released the Through-hole Standard because it was heavily flawed.

The IPC-7251 3-Tier system for Through-hole specified a strict annular ring for every hole size. That means for the Nominal Density Level a 0.25 mm hole produced a 0.20 mm annular ring and a 2.00 mm hole also got a 0.20 mm annular ring and a 3.00 mm hole had a 0.20 mm annular ring. This concept did not work at all and failed in the PCB design industry.

PCB Libraries created the "Proportional Pad Stack" and allows the user to define the minimum annular ring and then a multiplier of 1.50 X the Hole Diameter to calculate the Pad Size.

For a 1.00 mm hole X 1.50 = pad diameter of 1.50 mm (0.25 mm annular ring)
For a 2.00 mm hole X 1.50 = pad diameter of 3.00 mm (0.50 mm annular ring)
For a 3.00 mm hole X 1.50 = pad diameter of 4.50 mm (0.75 mm annular ring)

The larger the component lead the larger the hole and the larger the annular ring needs to be to securely solder the lead to the PCB.

Large leads need to carry the high current and thin annular rings fail.
Large leads need to carry the high current that require large annular rings to dissipate heat.
Large leads come with large packages that are heavy and need to be securely attached to the board.

]]> Tue, 14 Mar 2017 12:03:30 +0000 https://www.PCBLibraries.com/forum/library-expert-pth-calculator_topic2114_post8747.html#8747 <![CDATA[Library expert PTH calculator : The &#034;old&#034; version (IPC-7251)...]]> https://www.PCBLibraries.com/forum/library-expert-pth-calculator_topic2114_post8746.html#8746 Author: nw002
Subject: 2114
Posted: 14 Mar 2017 at 11:34am

The "old" version (IPC-7251) of the PTH calculator spreadsheet had different options for the 3 density levels (min, nom, max) and also gave you the padstack name for circular and square padstacks.

This was, I think, really useful!

Is there a reason why its been removed in the current spreadsheet?

regards
Nick

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