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TCAN1167-Q1: LDO output current capability

Daniel Wang (auto)
Intellectual 870 points
Part Number: TCAN1167-Q1

Hello team,

Normally the 5V LDO can output up to 100mA, but we noticed the description in datasheet: When a CAN bus fault takes place that requires additional current from the LDO, the total available current to external load components may be degraded. 

So I want to the lowest external supply current, and does the 100mA refer to internal LDO current or external Vccout current?

Cause customer need to use this power rail to supply for MCU, the worst Vccout current is important.

Thanks.

  • 0
    TI__Guru 52560 points

    Hi Daniel,

    We've assigned this thread to one of our CAN experts who should get back to you by tomorrow.

  • 0
    TI__Mastermind 49975 points

    Hi Daniel,

    The LDO for this device is rated for 100mA of external output current capability while also supplying the internal transceiver for nominal operation (around 70mA additional for dominant state in extended load conditions). This means that the total capability of the LDO is near 170mA.
    When a CAN bus fault occurs, the CAN transceiver could reach a current limit level of around 120mA. This will eat in to part of the 100mA output budget for the Vcc pin and could degrade performance here for the duration of the bus fault. Keep In mind that the dominant fault current is only drawn by the transceiver when the device is actively driving a dominant state into a strong bus fault. The CAN controller in the system should be able to recognize the loss of communication and stop the transceiver from transmitting into this bus fault before long. This will allow the transceiver to return to an idle state and allow the 100mA output to become stable again. 

    Let me know if you have any more questions. 

    Regards, 
    Eric Schott