PCB Libraries Forum : Rounded Rectangular Pad Shape https://www.PCBLibraries.com/forum/ Thu, 16 Apr 2026 03:19:09 +0000 Mon, 05 Feb 2018 08:18:24 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=2164 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[Rounded Rectangular Pad Shape : We can change the default LGA...]]> https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post9436.html#9436 Author: Tom H
Subject: 2164
Posted: 05 Feb 2018 at 8:18am

We can change the default LGA pad shape from Rounded Rectangle to Square. 

I think that's a good recommendation. 

Thanks!
]]> Mon, 05 Feb 2018 08:18:24 +0000 https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post9436.html#9436 <![CDATA[Rounded Rectangular Pad Shape : Hi,you are right, the tr value...]]> https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post9435.html#9435 Author: robmeyer
Subject: 2164
Posted: 05 Feb 2018 at 7:45am

Hi,

you are right, the tr value I have overseen in the Demopart.

And that the default rounded square for LGA could be changed to square I know. But in the earlier post it sounds that it should be per default square and not Rounded square. For DFN it was done but not for LGA. So what is correct?

Thanks
Robert
]]> Mon, 05 Feb 2018 07:45:55 +0000 https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post9435.html#9435 <![CDATA[Rounded Rectangular Pad Shape : In order for any Thermal Tab to...]]> https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post9432.html#9432 Author: Tom H
Subject: 2164
Posted: 02 Feb 2018 at 8:21am

In order for any Thermal Tab to have Rounded Corners, the user must enter a value for "tr" in the Calculator. I have never used Rounded Corners for Thermal Pads. Can you please send us a FPX file so we can prove it. 

The LGA has always had radius corners on square Leaded parts but that can easily be changed in Preferences. 

]]> Fri, 02 Feb 2018 08:21:08 +0000 https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post9432.html#9432 <![CDATA[Rounded Rectangular Pad Shape : Hello,in Version 2017.22 and 2018.1...]]> https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post9431.html#9431 Author: robmeyer
Subject: 2164
Posted: 02 Feb 2018 at 5:22am

Hello,

in Version 2017.22 and 2018.1 Library expert using other rules for the exception: Here it is per default rounded padshape under LGA. Also the Tab under QFN is now per default rounded. I have in mind, that in older Versions per default this was a square. Why this change?

Thanks
Robert
]]> Fri, 02 Feb 2018 05:22:07 +0000 https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post9431.html#9431 <![CDATA[Rounded Rectangular Pad Shape : Texas Instruments is starting...]]> https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post8965.html#8965 Author: Tom H
Subject: 2164
Posted: 08 Jun 2017 at 12:27pm

Texas Instruments is starting to promote 0.05 mm radius corners on their new parts. Other mfr.'s are starting to recommend rounded rectangle pad shape too, but even if they don't we still do.

All rectangular pad get a corner radius except DFN & LGA where the lead is BTC (Bottom Termination Component) and the pad size is equal to the Terminal Lead size or a 0.05 mm periphery.
]]> Thu, 08 Jun 2017 12:27:09 +0000 https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post8965.html#8965 <![CDATA[Rounded Rectangular Pad Shape : Two additional questions about...]]> https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post8964.html#8964 Author: bnoel
Subject: 2164
Posted: 08 Jun 2017 at 11:56am

Two additional questions about rounded rectangular pads:
1. If a mfr recommends rectangular pads should we change them to rounded rectangular pads?
2. What about large components?  For example, we have a 10.3mm X 10.3mm X 10.3mm Aluminum Electrolytic Cap with 4.3mm X 2.1mm pads.  Should we change these to rounded rectangles?
]]> Thu, 08 Jun 2017 11:56:23 +0000 https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post8964.html#8964 <![CDATA[Rounded Rectangular Pad Shape : In Library Expert Pro there are...]]> https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post8960.html#8960 Author: Tom H
Subject: 2164
Posted: 08 Jun 2017 at 7:53am

In Library Expert Pro there are Rule Settings for -

- Corner Radius % of pad width - the default is 25%
- Corner Radius Limit - the default is 0.25 mm
- Corner Radius Round-off - the default is 0.01

But these values are all user definable.

Rounded Rectangle pad shape conforms to the paste mask stencil aperture opening.
The stencil maker uses a laser to cut the aperture openings and rounds the corners of rectangular shapes to increase the stencil release yield.

Typical Stencil -

]]> Thu, 08 Jun 2017 07:53:28 +0000 https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post8960.html#8960 <![CDATA[Rounded Rectangular Pad Shape : Hello - We have a library including...]]> https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post8959.html#8959 Author: bnoel
Subject: 2164
Posted: 08 Jun 2017 at 6:13am

Hello - We have a library including almost 6000 parts.  Around 90% of our footprints have been created using rectangular pads.  We are considering migrating to rounded rectangular pads based on some of the recommendations I've seen on this forum.  

We use OrCAD Padstack Editor version 17.2-2016 for our padstack creation.  The Padstack Editor includes the option to convert rectangular pads to rounded rectangular pads.  

By default the editor calculates the radius of the rounded corners to be one third of the smaller of the 2 rectangle dimensions.  

For instance a rectangular pad of 1.20 mm X 0.80 mm when converted to a rounded rectangular pad would use 0.267 mm for the radius (0.80 / 3)  Is this an acceptable approach?]]> Thu, 08 Jun 2017 06:13:15 +0000 https://www.PCBLibraries.com/forum/rounded-rectangular-pad-shape_topic2164_post8959.html#8959