• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 255 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

SN65HVD231: CANH/L line voltage thresholds out of spec

VASANTH MITHILACODY62
Intellectual 475 points
Part Number: SN65HVD231

Hi,

We are using SN65HVD231 CAN transceiver in the BMS and it will communicate with the display product via CAN communication. Same transceiver SN65HVD231 used in both BMS and display units.

After few days of operation, the CAN transceiver is getting failed. Attached waveform for comparison before and after failure.

We are not able to find out the reason for failure. Let us know what can cause such abnormal behaviorBad trasceiver CANH, L.tifCANH-CANL_Good transceiver.tifGood trasceiver CANH, L.tif.CANH-CANL_Bad transceiver.tif

Regards,

Vasanth

  • 0
    TI__Guru 66442 points

    Vasanth,

    It looks like there is a leakage path on CANL causing the recessive voltage to not be driven to the correct value, or something is pulling the signal towards GND. You can see the overshoot on the signal reach the correct value and then immediately get pulled down too low. This could be caused by some kind of electrical overstress event. However, it looks like the differential should still give the correct output on RXD, is this true?

    • How many devices have seen this damage?
    • Can you share a schematic and/or a block diagram?
    • What else is on the CAN bus? How many other CAN nodes?

    Regards,

  • 0 in reply to Eric Hackett
    Intellectual 475 points

    Hi Eric,

    Yes, both CANH and CANL waveforms got issues but still differential voltage is within the limits and transceiver is able to communicate successfully.

    We have total 3 transceivers in the node. somehow third transceiver is not able to communicate.

    Tested with 2 systems, both got damaged. Both damaged transceivers have similar output characteristics.

    We have been testing with different scenarios to reproduce the failure case, but somehow not succeeded yet.

    Please share if you have any ideas what will cause such failures. Also share protection circuit to avoid this.

    Regards,

    Vasanth

  • 0 in reply to VASANTH MITHILACODY62
    TI__Guru 66442 points

    Vasanth,

    So only one transceiver of 3 is getting damaged? Which part of the system is the damaged transceiver in? 

    For electrical overstress, adding some capacitance to the bus pins can help slow down any fast transients that may be passing through and damaging the pins. Adding a TVS protection diode to both CANH and CANL will also help, a device like PESD1CAN is used by a number of customers.

    Is there any way a block diagram or schematic can be shared? If you don't feel comfortable sharing on a public forum, you can send it directly to me through email. If you click my username, you can find my email there.

    Regards,