PCB board design assessment

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Glebiys

Joined Mar 11, 2019
14
Hi,

I am designing a board that has 9 LEDs (SK6812) and a microcontroller (Atmega328P) that accepts UART commands and lights up the LEDs.

The design is almost ready, I have doubts about the earthen loops. I learned more about earthen loops only today. GND comes only through the terminal block located on top. The ground mounting holes do not have contact with the metal case, as the screws will be screwed into plastic.

Tell me, are there any earthen loops here? If so, how can I avoid them? The board has two layers.



 

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bertus

Joined Apr 5, 2008
20,180
Hello,

It could be the rendering, but I see a lot of spots where traces touch.
I circled a couple, but there are many more:

LED_PCB.png

Bertus
 

jpanhalt

Joined Jan 18, 2008
8,333
You can increase the "isolate" value for your polygon ground pour to fix that. Decreasing "width" may also help, but without knowing your current width, I would not recommend doing that. Too narrow a width can create problems with the board house.

Don't know how familiar your are with Eagle or your version. If you left click on the polygon outline using the "information" tool, you can make that change in the dialog screen that comes up.
 

bloguetronica

Joined Apr 27, 2007
1,372
The issues that Bertus pointed out are probably caused by rendering, and are not in the design itself. In Eagle, an isolation of 8 mils is quite standard and presents no issues. Unfortunately, I can't open .rar archives and thus, I can't confirm if your design is correct.

However, there are some changes I should suggest, especially on the top layer of your board. If you notice the traces marked in yellow, that is how you should fan out to the connector. There are some improvements near the micro-controller as well. Notice the two components circled in red. You should flip them around, so the ground plane is always on the left side.

On the bottom side, there are some things that could be improved as well. Again, see the traces marked in yellow. Also, some vias uniting the top and bottom planes wouldn't hurt your design. Put them near all the capacitors that use ground, right beside the ground pad, if possible.

Of course my assessment could be wrong. I don't have access to the schematic. Could you provide one (in a .zip file, or in PDF)?

Kind regards, Samuel Lourenço
 

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