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 ground polygon in between parallel bus lines 

Last post Mon, Sep 23 2013 6:44 PM by redwire. 1 replies.
Started by baltING 23 Sep 2013 04:17 AM. Topic has 1 replies and 241 views
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  • Mon, Sep 23 2013 4:17 AM

    • baltING
    • Not Ranked
    • Joined on Mon, Sep 23 2013
    • Posts 1
    • Points 20
    ground polygon in between parallel bus lines Reply

    Hello,

    I just finished a design of parallel a RGB bus to pump image data into a TFT display. The bus frequency is 25MHz. To prevent crosstalk between the lines i placed ground polygons in between each line on the pcb. I wondered if this might harm the signal integrity due to a higher capacitance to ground of each track. The formular for the capacitance of a simple plate capacitor gives me about 2pF (length: 80mm, 35µ Cu, epsilonR of solder mask = 3.5) so there should be no problem. After all this is just a question about style: is it useful and usual in some cases to place ground polygons between bus lines?

    Best regards!

    • Post Points: 20
  • Mon, Sep 23 2013 6:44 PM

    • redwire
    • Top 10 Contributor
    • Joined on Thu, Jul 17 2008
    • Allen, TX
    • Posts 876
    • Points 13,500
    Re: ground polygon in between parallel bus lines Reply

    There is so much hiding behind the answer to this question so a little homework is in order.  Check out this article.  Also search for Dr. Howard Johnson and guard traces on google and see what you find.

     

    http://www.altera.com/technology/signal/columns/2006/2006-10-oct_1.html

    • Post Points: 5
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Started by baltING at 23 Sep 2013 04:17 AM. Topic has 1 replies.