https://devzone.nordicsemi.com/f/nordic-q-a/110310/nrf5340-soldering-issueHello, I am working on a custom PCB that involves the NRF5340 and our first iteration of PCBs had soldering issues during assembly for the nRF5340. The nRF5340’s footprint in my design is copied from the example footprint given by Nordic . I asked theen-USTelligent Community 13Tue, 20 May 2025 09:56:22 GMThttps://devzone.nordicsemi.com/thread/536156?ContentTypeID=1Tue, 20 May 2025 09:56:22 GMT137ad170-7792-4731-bb38-c0d22fbe4515:79e5144e-7f22-4552-9ac0-8bdb15ee07f0HelenRowe<p>@<a href="https://poor-bunny.com">poor bunny</a>,&nbsp;I think reducing the thermal via hole size to 8mil may cause insufficient solder to escape through the via, resulting in excess solder and assembly errors.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/479748?ContentTypeID=1Fri, 19 Apr 2024 14:09:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7c961464-f626-4fe0-825b-d38c51da9635LittleBush3<p>Thank you for your response Simonr!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/479671?ContentTypeID=1Fri, 19 Apr 2024 10:58:04 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9800dabc-aa88-4a10-8b7a-5a99d147b569Simonr<p>Hi</p> <p>Changing the via hole size shouldn&#39;t be an issue here, but we see that you&#39;re using through hole vias. Than some of the solder paste will be &quot;sucked&quot; into the hole, and if you then lower the diameter of the hole there will be room for less solder paste which might be why you&#39;re having issues with too much paste under the device.</p> <p>Best regards,</p> <p>Simon</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/479464?ContentTypeID=1Thu, 18 Apr 2024 13:37:14 GMT137ad170-7792-4731-bb38-c0d22fbe4515:792c0ca4-f5b9-4548-a5ef-ab0b58f10c13LittleBush3<p>After looking through the application notes mentioned by Simonr and reviewing the Nordic footprint example, I have finished with this as a final set up (22milx22mil solder paste windows and 8mil diameter thermal via holes):</p> <p><img style="max-height:240px;max-width:320px;" alt=" " src="https://devzone.nordicsemi.com/resized-image/__size/640x480/__key/communityserver-discussions-components-files/4/Top-Paste-Current-Solution.png" /></p> <p>One item that I noticed was changed by another designer on my team was the size of the thermal via holes in the die pad. He had changed them to be 8mil diameter holes instead of the default 12mil diameter holes. Could the holes being shrunk be the reason for the default solder paste windows leaving too much solder and causing assembly issues? Does anyone see a reason why leaving the thermal vias smaller and making the solder paste windows smaller to compensate would be an issue?</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/479446?ContentTypeID=1Thu, 18 Apr 2024 12:57:36 GMT137ad170-7792-4731-bb38-c0d22fbe4515:484f1972-c0e4-4ddc-90a1-5ef331e310e4LittleBush3<p>Ok. Thank you for the information. I will make sure to use the information from the application notes mentioned. Thank you!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/479386?ContentTypeID=1Thu, 18 Apr 2024 10:32:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2a5c9353-b68c-498b-80fe-fa598b889b21Simonr<p>Hi</p> <p>If there is too much paste on your end it should be perfectly fine to reduce the size of them. We have some circuit board guidelines, but nothing specifically for the nRF5340. Please refer to the ones we have available here:&nbsp;<a href="https://infocenter.nordicsemi.com/topic/struct_appnotes/struct/appnotes.html">https://infocenter.nordicsemi.com/topic/struct_appnotes/struct/appnotes.html</a></p> <p>Best regards,</p> <p>Simon</p><div style="clear:both;"></div>