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SN65HVD235: SN65HVD235 CAN Transceiver

Enrique Valdez
Prodigy 90 points
Part Number: SN65HVD235

SN65HVD235DR, RS at continuous use with a 51KOkm. setup to run 250k Baud rate in software. Will the component be damaged if we attempt to run it at 500K baud rate?

 

We currently have a customer that was running them as 500K and the following happen.

 

1 unit exhibit problems with message transfer communicating to an external device

1 unit CAN does not start after initially communicating to an external device

1 unit still works with no issue communicating to an external device

 

We are trying to see if due to the RS pin pull down with a 51KOhm will create this issue so we can instruct our customer on why these issues happen.

  • 0
    TI__Guru 62910 points
    Hi Enrique,

    No, operating the part at a faster baud rate should not cause any damage to the IC. Can you please provide more info on the units that exhibit message transfer problems and problems starting up? What specifically are you observing with respect to the CAN transceiver?

    Thanks,
    Max
  • 0 in reply to Max Robertson
    Prodigy 90 points

    Hi Max:

    We experienced and issue were the customer measured voltage and got the following readings

    In your opinion how can this happen.

    Thanks

  • 0 in reply to Enrique Valdez
    TI__Guru 60112 points

    Enrique,

    Thank you very much for the oscilloscope captures, I have a few clarification questions.

    For the Power-Supply voltage, where exactly is this voltage being applied? In the 8V and 16V cases, is the communication working correctly? And are all of these images at 500kbaud?

    Regards,

    Eric Hackett

  • 0 in reply to Eric Hackett
    Prodigy 90 points

    Hi Eric:

    The input voltage to the device is always 3.5 for Vcc. We also noticed that at 8V and 16V is working correctly but at the rest it seems to fallow the input voltage to the unit. We have a voltage regulator that can input from 8 to 32V and it will regulate it to 3.5V that is the Vcc of the CAN module.

    There is no direct pat from the input voltage of our unit to the Vcc or CAN_L or CAN_H from our unit. That is why we are asking the question if there has ever been a case similar to this, we suspect it was induced by the end customer but we need to check with the vendor.

    Thanks

    Enrique

  • 0 in reply to Enrique Valdez
    TI__Guru 60112 points
    Enrique,

    The only case where I've seen this happen is, like you said, when there is a direct connection, which typically happens if there is damage present which would cause a short-to-battery/supply condition. That kind of damage typically happens when voltage spikes on the bus cause a leakage path internal to the device to the supply to happen, but since there is no direct path to the supply on our device, I don't see how that would be possible. No damage will happen running at 500kbaud either.

    What else is connected to this bus?

    Regards,
  • 0 in reply to Eric Hackett
    Prodigy 90 points

    Hi Eric:

    The unit was running at 500Kb and it was connected to another CAN device.

    We were not able to reproduce the issue to match the 2 channels reading, only 1 when we applied input power to our modem to either CAN H or CAN L with out a terminating resistor.

    We just need to know if your team agrees that this could have been only cause by external application of power to the CAN H or CAN L since the device was received at our facility and we were not able to replicate the reported failure. (NPF).

    Thanks
    Enrique Valdez

  • 0 in reply to Enrique Valdez
    Prodigy 90 points
    Hi Eric:

    Also the reading for 8V and 12V were different than the ones provided since they seem like the device was working normal, in our reproduce test they were still following the input voltage as expected not like images provided.

    We suspect a setup issue.

    Thanks
    Enrique Valdez