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SN65HVD1050: CAN Bus-Fault Protection.

Kengo.Y
Guru 10745 points
Part Number: SN65HVD1050

Hi team,

The IC broke when 32VDC was applied to CANH and CANL

I believe there is fault protection, but why was it broken?
I'd like to know what caused it to be broken.

BR,
Kengo.

  • 0
    TI__Mastermind 19640 points

    Hi Kengo,

    I'm sorry to hear that. The device has a bus fault protection up to 40V, so yes 32V DC on the CAN bus will not damage the device. There might be some other reason that cause the damage, for example if a short to battery happens while CAN communication is occurring and there's a common-mode choke on the CAN bus, there is a chance that the voltage could rise to higher than the absolute maximum due to inductive kickback. Overheating will also cause damage to the device. If too much heat builds up in the system without dissipating excess heat, the device can eventually sustain overtemperature damage. 

    Is there any ESD protection on your CAN bus? 

    Regards,

    Sean

  • 0 in reply to Sean Guo
    Guru 10745 points

    Hi Sean,

    Thank you for your reply.

    Yes, I used RSB27F2T106 on CANH/L line.

    Are there likely to be any factors?

    BR,
    Kengo.

  • 0 in reply to Kengo.Y
    TI__Mastermind 19640 points

    Hi Kengo,

    SN65HVD1050 is a old device, it does not integrate ESD protection. This TVS diode also seems not designed for automotive or industrial applications. A surge transient during powerup may be one factor to cause the damage. If you replace the broken device with a new one and do the same test, will it still be broken at 32V?

    Can you share the schematic and capture some waveforms so we can provide further help to find the cause. I also recommend to use TCAN1044A for improved fault protection.

    Regards,

    Sean