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[SN65HVD01] The trace impedance of RS485

daniel
Genius 5095 points

Other Parts Discussed in Thread: SN65HVD01

Hi team,

For RS485 traces on SN65HVD01 A/B pin.

1. Does these two traces "differential" in layout design?

2. Does these two traces require impedance control in layout design? If yes, what is the impedance value?

Thanks

  • 0
    TI__Guru 62920 points
    Hi Daniel,

    RS-485 traces are typically routed as differential pairs with 120-Ohm differential characteristic impedance. The differential routing helps reduce common-mode noise emissions and improve common-mode noise immunity of the system. The impedance control allows for the PCB transmission lines to match the characteristic impedance of the cabling that is typically used and the termination resistances, which are typically 120 Ohms per the RS-485 standard's guidelines. Maintaining a well-controlled impedance helps preserve high-speed signal integrity by preventing signal reflections due to impedance discontinuities.

    I hope this helps; please let me know if you have any other questions.

    Max