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What beginners mistakes have I made?

mpiechotka

Sorry if this is incorrect forum/basic question. While I have a background in programming and some experience with FPGAs the I didn't know much about EE before. I run into a hobby project for which I'd like to create a PCB and soon I found myself in deep waters. So I decided to step back and create a simple PCB to learn basics. I tried to create a simple AVR board with an GPIO header, JTAG connector and USB-to-UART bridge. I've created something but I'm sure I've done many basic mistakes and strange decisions so I'd be grateful for pointing them out.

 

PS. I know there is no power switch but I couldn't find one on with eagle library.

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  • Things you might consider:

     

    1) use a ground plane on the lower (non component side) of the baord.

    2) keep all the components on one side (if you will hand solder a couple of prototypes this doesn't matter but for production it always costs more to populate both sides.)

    3) don't ever make sharp V shapes with track - it causes problems in etching

    4) try to take tracks out of sm components on axis and the same for all

    5) you have some very thin tracks and some tiny vias - you don't need to use such aggressive design rules a board like this.

     

    MK

  • in reply to michaelkellett

    Thanks Michael

     

    AD 3. Thanks - I haven't realized that one - the explanations I read was about current flow which is why I tried to kept angles for flow <45°.

     

    AD 4. Sorry - I have no clue what you mean.

     

    AD 5. I use default 6 mils for signals and for power/ground signals that supply a lot of components I choose 20. I'm not sure what to choose if default are not correct - obviously the thinner the track the less conductivity it has and I know I could calculate in principle the resistance but probably there are some good rules of thumb.

  • in reply to mpiechotka

    It might be worth increasing the trace width to the power pins on the USB connector...

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