PCB Layout Questions

Discussion in 'General Electronics Chat' started by tracecom, Jun 2, 2010.

  1. tracecom

    Thread Starter AAC Fanatic!

    Apr 16, 2010
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    I am using ExpressPCB to lay out the first PCB I have done in many years, and even though it is a simple board, I have some questions.

    1. ExpressPCB recommends .150" wide tracks for up to 6 amps. If I put identical .080" wide tracks on both the top and bottom layers, will that be as good?

    2. What about power and ground traces; I know they should emanate from a central rail, but is it good practice to "loop" the tracks or to maintain a "star" configuration.

    Any other advice is appreciated.
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    If this is a prototype, and not something that goes into production. You can solder a non isolated coper wire to the track, or just melt solder metal ontop of the track.
     
  3. tracecom

    Thread Starter AAC Fanatic!

    Apr 16, 2010
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    The board I am laying out is not for production, but will (I hope) be used for field trial. Because of this, I would like to avoid adding wire/solder. Thanks for the suggestion.
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    Two parallel wires will work.
     
  5. eng1ne

    Member

    Dec 4, 2009
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    Your grounding requirements depend entirely on the circuit. A good rule is to separate analog and digital grounds; both should terminate at one point as you state.
     
  6. retched

    AAC Fanatic!

    Dec 5, 2009
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    The grounds should terminate as close to the external power source connector as you can get it.

    Actually there are a few hundred ways of accomplishing these tasks. It depends on how fast the signals you are using, and, how noisy the environment is.

    Heat dissipation should also be considered while running traces. A copper fill can be used as an effective heat sink in many applications.
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    you need to state your pcb copper thickness (1/2 oz, 1 oz, 2 oz,etc...) before we can tell you if the trace is sufficient for 6 Amps. Also your acceptable temp rise over ambient. Don't forget any heat input from components attached to that trace.

    http://www.desmith.net/NMdS/Electronics/TraceWidth.html
     
  8. cmancuso

    New Member

    Jun 7, 2010
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    For the ground plane, if you are getting the more expensive boards for Express PCB you could use a solid ground plane on the bottom layer of the board, and making sure you have no islands on the ground plane.
     
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