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SN65HVD232: Maximum series resistance on CANH and CANL lines

Jason McKay
Prodigy 50 points
Part Number: SN65HVD232
Other Parts Discussed in Thread: TINA-TI

Support Path: /Product/Development and troubleshooting/Find key information on a device/

What is the largest series resistor the SN56HVD CAN transceiver can support on the CANH and CANL lines?  I am not referring to the termination resistor(s).

Are 10 ohm resistors going to be an issue?  100 ohms? 1k ohms?

  • 0
    TI__Expert 6955 points
    Nota,

    The max series resistance of the bus lines will be determined by the data rate you intend to use. The series resistor and the bus cable resistance and capacitance will form an RC filter that will limit your switching frequency and therefore data rate.

    -Lucas
  • 0 in reply to Lucas Schulte9
    Prodigy 50 points
    Lucas,

    Thanks for the response. Do you have any technotes to assist with these calculations? Is there a Tina-TI model available that could be used to simulate the bus scenario?

    Regards,
    Nota
  • 0 in reply to Jason McKay
    TI__Expert 6955 points
    Nota,

    Unfortunately there aren't any notes on this that I am aware of. One other thing I forgot to mention is the voltage divider that putting a series resister in the bus lines would cause. The series resistor and the termination resistor would act like a voltage divider that would reduce the amplitude of the differential signal being transmitted. You have to ensure the voltage divider isn't significant enough to attenuate the signal beyond the minimum thresholds. What is the purpose of the series resistor?

    -Lucas
  • 0 in reply to Jason McKay
    Prodigy 50 points

    I found this reference in a totally unrelated TI datasheet.  I think this answers my question.