I2C Layout Methodology

Discussion in 'General Electronics Chat' started by cava0035, May 24, 2012.

  1. cava0035

    Thread Starter New Member

    Apr 5, 2008
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    0
    I'm using a PCA9532PW IC that uses I2C. I have four of the ic's on a 10" x 1.5" pcb. They are evenly destributed in the vertical direction. I'm not clear what is the correct layout method for the SDA and SCL lines. Can I use a two layer board or is a four layer board best?

    Thanks,
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    There are no particular PCB layout requirements for SDA and SCL in I2C.
     
  3. coldpenguin

    Active Member

    Apr 18, 2010
    165
    9
    Is there any difference capacitance/frequency wise between a star or ladder layout? I know with 1-wire, for long runs there was a slight change suggested.
    10" wouldn't be long though.
     
  4. MrChips

    Moderator

    Oct 2, 2009
    12,442
    3,361
    You obviously know what you are talking about.

    When you include wire length, frequency and capacitance, you will start to degrade your signal and integrity. If you limit all three then there is little difference between a star or ladder layout.

    If you encounter problems with the above and you have to include series resistors and line terminating resistors, then a ladder network would be better.
     
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