+ Post New Thread
Results 1 to 8 of 8
  1. #1
    Newbie level 2
    Points: 1,019, Level: 7

    Join Date
    Apr 2007
    Posts
    2
    Helped
    0 / 0
    Points
    1,019
    Level
    7

    thumb rule current through a pcb via

    Hi, I'm wondering if anyone can share the experience/ rule of thumb of the current capacity for vias in PCB layouts. THanks

    •   AltAdvertisment

        
       

  2. #2
    Full Member level 6
    Points: 4,262, Level: 15

    Join Date
    Dec 2005
    Location
    BANGALORE
    Posts
    373
    Helped
    47 / 47
    Points
    4,262
    Level
    15

    Re: Current capacity for PCB vias

    Hi,

    Check this pdf for above subject,

    http://www.ultracad.com/articles/viacurrents.pdf


    Hope this helps you.


    Regards

    Ramesh


    1 members found this post helpful.

  3. #3
    Member level 1
    Points: 1,285, Level: 8

    Join Date
    Feb 2007
    Posts
    40
    Helped
    1 / 1
    Points
    1,285
    Level
    8

    Re: Current capacity for PCB vias

    I was just looking up this topic the other day and found this website:

    http://circuitcalculator.com/wordpre...ia-calculator/


    You can calculate the resistance of the via which you can then apply to your own current usage and see what kind of loss and heat generation will occur.



    •   AltAdvertisment

        
       

  4. #4
    Newbie level 2
    Points: 1,019, Level: 7

    Join Date
    Apr 2007
    Posts
    2
    Helped
    0 / 0
    Points
    1,019
    Level
    7

    Current capacity for PCB vias

    Thanks, Ramesh, but that paper doesn't give any rule of thumb to do it.

    Added after 5 minutes:

    Hey, OradFarez, thanks for sharing the tools. Could you give me an idea what's criteria to choose the via size using that tool, i mean, what's maximum loss is allowed??

    For myself, I just use the circumlength of the fininshed via as the trace width, then using this tool to check it:

    h**P://circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/

    Do you guys think it's correct??



  5. #5
    Full Member level 6
    Points: 6,652, Level: 19

    Join Date
    Jul 2001
    Posts
    322
    Helped
    32 / 32
    Points
    6,652
    Level
    19

    Re: Current capacity for PCB vias

    running2k

    I suggest to you the reading of book "The Circuit Designer's Companion" by Tim Willians. In this book you can read "the characteristic impedance for a copper track over a ground plane on a double-side work out around 100-150 ohm for narrow tracks on 1.6 mm thickness, reducing to around 75-100 ohm on 0.7 mm". The book includes figures that show the theoretical resistance for various thickness of copper track per centimetre, etc.

    Regards, svicent



    •   AltAdvertisment

        
       

  6. #6
    Advanced Member level 5
    Points: 16,636, Level: 31

    Join Date
    Jul 2001
    Location
    Oberon
    Posts
    1,897
    Helped
    442 / 442
    Points
    16,636
    Level
    31

    Current capacity for PCB vias

    Rule of thumb:
    A via of x diameter will carry the same current as a track on the same board of 3x width.



  7. #7
    Full Member level 6
    Points: 4,262, Level: 15

    Join Date
    Dec 2005
    Location
    BANGALORE
    Posts
    373
    Helped
    47 / 47
    Points
    4,262
    Level
    15

    Re: Current capacity for PCB vias

    Hi,

    Btbass,could you please shed some light on the rule of thumb ur talking about,do appreciate if could upload the link for the same.


    Regards

    Ramesh



  8. #8
    Advanced Member level 5
    Points: 16,636, Level: 31

    Join Date
    Jul 2001
    Location
    Oberon
    Posts
    1,897
    Helped
    442 / 442
    Points
    16,636
    Level
    31

    Current capacity for PCB vias

    The Circumference of a circle is Pi x Dia.
    If you could straighten out your via, you would have a track through the board of Pi x Dia width.

    Simplified? yes, but it is a rule of thumb.



--[[ ]]--