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SN65HVD230: Can one CAN transceiver be powered off 5V while another transceiver on the bus is powered off of 3.3V?

oscar n
Prodigy 70 points
Part Number: SN65HVD230

Hi there, are there any possible issues with having one upstream SN65HVD230 running at 5V, while other CAN nodes with SN65HVD230 are running at 3.3V? Any potential backfeeding issues? Or does the transceiver know to use the correct recessive level voltage? Thanks!

  • 0
    TI__Guru 53555 points

    Hi Oscar,

    Yes! 3.3V supplied CAN transceivers can operate on the same bus as 5V CAN transceivers. The reason this is possible is because the CAN receivers are only sensitive to the differential between CANH and CANL. Because 3.3V supplied transceivers are capable of producing a valid dominant level (>900mV) between CANH and CANL, their output is recognized by all nodes as a valid signal regardless of local supply level. 

    The drawbacks of using a mixed node network is that the common mode level of the bus will shift as the bus hands off between transceivers with different supply levels. While this is not a problem for the CAN receivers (which ignore the common mode), this can have an impact on the radiated emissions of the system. 

    Section 11.3.1.3 of the SN65HVD230 datasheet also covers the topic of Interoperability of 3.3-V CAN in 5-V CAN Systems.

    Let me know if you have any more questions. 

    Regards,

    Eric Schott.