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    standard difference signal lines in PCB layout

    Hi, i wanted to ask how are the standard difference signal lines rules when drawing differential lines in PCB layout? (please help, i need this as soon as it can be)

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    Re: standard difference signal lines in PCB layout

    More info please:
    But you need to know required characteristic impedance required for the signals, number of layers (and thus dielectric thickness), track width, etc etc.



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    Re: standard difference signal lines in PCB layout

    Quote Originally Posted by marce View Post
    More info please:
    But you need to know required characteristic impedance required for the signals, number of layers (and thus dielectric thickness), track width, etc etc.
    Hi, thanks for the reply, i need to know the distance between tracks, track width and max length of the lines (tracks) between D+ and D- of USB lines, and between UART Rx and Tx lines. What values are the appropriate for a good performance?.



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    Re: standard difference signal lines in PCB layout

    http://www.skottanselektronik.com/
    Impedance calculator.
    USB D+/D- 90ohm diff impedance, max skew between lines 1mm (6 layer stripline routed approx. 0.17/0.17/0.17)
    UART lines ref data sheet, but generally don't have to length match Rx Tx only diff pairs



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    Re: standard difference signal lines in PCB layout

    Quote Originally Posted by marce View Post
    http://www.skottanselektronik.com/
    Impedance calculator.
    USB D+/D- 90ohm diff impedance, max skew between lines 1mm (6 layer stripline routed approx. 0.17/0.17/0.17)
    UART lines ref data sheet, but generally don't have to length match Rx Tx only diff pairs

    Thanks for the reply. And which would be the right width for each USB line (D+/D-)?



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    Re: standard difference signal lines in PCB layout

    Provide number of layers, PCB material (FR4) I presume, layers you are going to route d-+ on (inners or outers).



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    Re: standard difference signal lines in PCB layout

    There is no "standard". Depends on stackup.

    As for UART: TX and RX do not form a differential pair, rather the contrary.



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