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TCAN1043-Q1: device behavior if no series resistor on the WAKE input terminal and 12V is directly applied?

Viktorija Cecil
Mastermind 18511 points

Part Number: TCAN1043-Q1

What happens to TCAN1043-Q1 if there is no series resistor on the WAKE input terminal and 12V is directly applied?

Thanks

Viktorija

  • 0
    TI__Guru 74972 points

    Viktorija,

    The series resistance is meant to protect the WAKE pin against in-rush current when using a low-side/high-side switch to toggle the state of the pin for local wake-up. If the pin is constant tied to VBAT, there is no need for a series resistor to protect against potential damage.

    Please let me know if you have any other questions.

    Regards,

  • 0 in reply to Eric Hackett
    TI__Mastermind 18511 points

    Eric, thanks. 

    In the instances where customer didn’t always have a constant 12V battery applied and instead it was ignition from the vehicle. Would we have issues with the transceiver? If so, what types of failure modes would we see? Would it be a total loss of the transceiver? Would only the LWU functionality be destroyed?

  • 0 in reply to Viktorija Cecil
    TI__Guru 74972 points

    Viktorija,

    Do you mean ignition as a switch for the battery to apply to WAKE? Or the supply to the entire transceiver and the WAKE pin at the same time?

    If it's the former, this may cause issues and I would expect issues just with the WAKE function and pin. With a voltage applied to WAKE more current would be sunk by the pin because a lower-impedance path to GND would be created with the damage.

    Regards,

    Eric Hackett

  • 0 in reply to Eric Hackett
    TI__Mastermind 18511 points
    • Typically in our applications, we’ve been using this part as Battery connected directly to VSUP and GND. The ignition from the vehicle is then tied directly to the WAKE input terminal.
    • That being said, on benchtop, we’ve been supplying a 12V power supply to VSUP and GND. When desired, the WAKE input terminal is attached to the same supply.

     Are either of these cases an issue?

  • 0 in reply to Viktorija Cecil
    TI__Guru 74972 points

    Viktorija,

    No, neither of these cases should be an issue.

    Regards,