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SN65HVD230: CANH and CANL pins protection

Part Number: SN65HVD230
Other Parts Discussed in Thread: SN65HVD234, SN65HVD233, SN65HVD235

Hi Team,

Our customer is using the SN65HVD230 for their sensor design. They intend to bring the CANH and CANL from the SN65HVD230 outside the sensor for the user to connect to their bus.  Is this the correct way of doing this? Is there also a way to protect the lines if someone were to apply 24VDC and ground to these pins accidently?

Thanks in advance!


Kind Regards,

Jejomar

  • Jejomar,

    Thanks for bringing this to E2E.

    When you say "outside the sensor", do you mean the CAN bus to go off the sensor board to a connector?

    The best way to do this would be to put a diode with a clamping voltage lower than 16V so the CANH and CANL pins don't get destroyed if a 24V short were to occur.

    Is the customer willing to switch to a different device? Depending on what features the customer is using on the SN65HVD230, the SN65HVD233, SN65HVD234, and SN65HVD235 are available with high CAN bus voltage protection (+/-36V).

    Regards,

  • Hi Jejomar,

    The CAN pins of these transceivers are more resilient than your average digital pin as they expect to be connected in some way to the outside world. These devices are rated for ESD events to increase reliability when exposed to transients from other machines or users. For particular cases where bus faults (accidental connections) are anticipated, transceivers with bus-fault protection features can be used to ensure the device survives such incidents. In this case, I'd recommend SN65HVD234 which has a higher bus fault rating of +-36V on the CAN pins. Extra protection can also always be provided by external protection devices such as TVS diodes.

    Let me know if this solution works for the customer and if you have any more questions.

    Regards,
    Eric Schott