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TCAN1145-Q1: CAN chip is burned out by short circuit test

?? ?
Prodigy 10 points
Part Number: TCAN1145-Q1
Other Parts Discussed in Thread: TCAN1042H

TCAN1145-Q1, in normal operation, CANH and CANL will be burned out if short-circuited to 32V.

  • 0
    Prodigy 10 points

    The manual says that it can withstand 58V, and the actual test of 32V in normal working mode is burned out, what is the reason

  • 0 in reply to ?? ?
    TI__Genius 15390 points

    Hi,

    Are you applying the voltage to each CANH and CANL relative to GND? Is is possible there is a voltage spike initially that goes over 58V before settling?

    Regards,

    Sean

  • 0 in reply to Sean Guo
    Prodigy 10 points

    The test is CANH and CANL are connected to the ground 32V respectively. Our power supply equipment is professional, with oscilloscope test, no overshoot phenomenon; The same environment was tested with TCAN1042 without problems.

  • 0 in reply to ?? ?
    TI__Genius 15390 points

    Hi,

    I'm sorry to hear that. When you doing short circuit test sometimes the voltage on the pin will not necessarily be the same with the DC voltage source output. Is there common mode choke on the bus?  The use of common-mode chokes in CAN systems might cause extremely high transient voltages that may be generated by the inductive flyback during a short circuit of a CAN bus line to a dc voltage. As the transceiver drives the bus level from dominant to recessive or recessive to dominant during this short-circuit condition, the change in current through the common-mode choke may flyback in excess of 65 V.

    ?? ? said:
    The same environment was tested with TCAN1042 without problems.

    Was that TCAN1042H? The H version can survive up to ±70V.

    Would you also please share the schematic. You may consider to place a 1 Ohm series resistor on each CAN line, it will help to reduce the transients but degrade the signal integrity.

    Regards,

    Sean