PCB Libraries Forum : Calculator QFP Pad Stack Invalid Number

PCB Libraries Forum : Calculator QFP Pad Stack Invalid Number https://www.PCBLibraries.com/forum/ Tue, 21 Apr 2026 13:04:31 +0000 Wed, 22 Jun 2016 08:07:52 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=1915 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[Calculator QFP Pad Stack Invalid Number : The only thing I see that's...]]> https://www.PCBLibraries.com/forum/calculator-qfp-pad-stack-invalid-number_topic1915_post7800.html#7800 Author: Tom H
Subject: 1915
Posted: 22 Jun 2016 at 8:07am

The only thing I see that's wrong is the "b" lead width has no tolerance and it should, but that would not cause the error but it will cause a bad Land Pattern Footprint. An insufficient pad width.

Are you using V2016.07?

Here is what I get when I enter your dimensions -

]]> Wed, 22 Jun 2016 08:07:52 +0000 https://www.PCBLibraries.com/forum/calculator-qfp-pad-stack-invalid-number_topic1915_post7800.html#7800 <![CDATA[Calculator QFP Pad Stack Invalid Number : There are couple things that might...]]> https://www.PCBLibraries.com/forum/calculator-qfp-pad-stack-invalid-number_topic1915_post7799.html#7799 Author: Jeff.M
Subject: 1915
Posted: 22 Jun 2016 at 8:05am

There are couple things that might lead to a negative paste mask value

The b dimension seems pretty small. Are you sure it's 0.08 mm?

I checked a few comparable datasheets and the terminal width is typically 0.17 - 0.27.

This small dimension with a small side protrusion goal and a shrink on the solder mask could add up to a negative.

]]> Wed, 22 Jun 2016 08:05:27 +0000 https://www.PCBLibraries.com/forum/calculator-qfp-pad-stack-invalid-number_topic1915_post7799.html#7799 <![CDATA[Calculator QFP Pad Stack Invalid Number : Hello,found a little thing here....]]> https://www.PCBLibraries.com/forum/calculator-qfp-pad-stack-invalid-number_topic1915_post7796.html#7796 Author: Stadler_s1
Subject: 1915
Posted: 22 Jun 2016 at 5:33am

Hello,

found a little thing here. I Created a 176pin QFP with Datasheet.

the Paste Mask Top created a -Size and the Pad Stack Manager says Error.

]]> Wed, 22 Jun 2016 05:33:14 +0000 https://www.PCBLibraries.com/forum/calculator-qfp-pad-stack-invalid-number_topic1915_post7796.html#7796