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Feedback on a simple layout

cBegue , 04-21-2021, 07:51 AM
Hello there, I created a simple 2 layers expansion board to try an EDA tool. It is made to connect a development board's GPIOs to SMD push buttons, LEDs and a DIP Switch 4. The connection from the development board to the expansion board is made with a 2x10 header. The uC input GPIOs are to be pulled up and debounced internally so I simply connected these to GND for the push buttons and the DIP Switch.
I have a big ground plane on the top and bottom layers. I placed many more vias than necessary regularly on the whole ground plane, I am not sure if the regular vias on the outline are good (protection against EMI) or useless though considering both ground planes cover the entire signal layers. I initially thought about making a ground plane only on the right side of the board around the GND connections on the top layer, would that have been a good option ? I used wide 25mils traces because I could but I guess thinner traces more isolated from one another would have been better ? Would you have placed the traces differently ? Should I isolate them more from the ground plane ? The gerber viewer top and bot views are attached.
Looking forward to your feedback.

qdrives , 04-21-2021, 09:30 AM
1) For cross talk it is better to have thinner traces and more space between them.
2) For ESD it is better to add some (10nF) capacitors for the pushbutton and switches when going to MCU. It also improves the reliability of them a bit.
3) What is the pull-up resistance in the MCU? With the capacitor (2) the timing can be varying a lot.

robertferanec , 04-23-2021, 04:51 AM
I agree with @qdrives Especially, I do not know why, but many people route signals unnecessary close to each other - even there is plenty of space around.

I would recommend to watch my youtube videos about crosstalk:
- What Every PCB Designer Should Know - Crosstalk Explained (with Eric Bogatin) https://youtu.be/EF7SxgcDfCo
- Understanding Crosstalk in PCB Layout - You may wish you knew this before (with Eric Bogatin) https://youtu.be/5EeQPxRdurk
- 3 Simple Tips To Improve Signals on Your PCB - A Big Difference https://youtu.be/CDJn-35W8sg
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