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SN65ALS180: Special Impedance for layout

Nishalini Baskaran
Prodigy 250 points
Part Number: SN65ALS180


Is there any special impedance for layout or standard can be follwed? can you please confirm is standard 120 ohm 

  • 0
    TI__Guru 58117 points

    Hi Nishalini,

    We are currently on a holiday. Please give until next week for an update, thanks.

    Best Regards,

    Michael.

  • 0
    TI__Guru* 77341 points

    Hi Nishalini,

    Impedance match should match the transmission line. This depends on the cable you use. For RS485, it is more common to have impedance controller cables of 120 ohm. Some cables have impedances of 100 ohms which is more common with RS422 systems. 

    3074F Technical Data Sheet

    An example of a cable above. You can look at the nominal impedance value in the datasheet of the cable which shows 120. If you know your cable for your system, then you should impedance match the traces to match that value.

    I also recommend you match the length of the traces for the A/B pins since these are differential pins.

    -Bobby