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TCAN2450-Q1: need for a separate external LDO?

JOONGGEON LEE
Prodigy 70 points
Other Parts Discussed in Thread: TCAN2450-Q1

Regarding TCAN2450-Q1, as far as I understand, there is an LDO inside VCC1, VCC2, so there is no need for a separate external LDO, VCC1 can have 3.3V or 5V output, and VCC2 can have a fixed output of 5V, right?
Also, is it correct that the 5V output of VCC2 is input to VCAN so that CAN FD transceiver is possible?

  • 0
    TI__Mastermind 33440 points

    Hello JOONGGEON,

    Your understanding is correct.  The VCC1 voltage is the output voltage of a BUCK and can be set to either 3.3V or 5V through the VSEL pin.  VCC2 is always 5V and can be used to supply the VCAN supply input and prevent the need for an external 5V LDO.  However, an external 5V supply could also be used for VCAN if desired.

    Note that VCC2 is short to battery protected but VCAN is not.  So if VCC2 is used to supply VCAN, then the VCC2 voltage should not be taken off the board where a short to battery fault could occur and damage the CAN transceiver.

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Prodigy 70 points

    Thank you for replying.

    I'd like to ask you something else.
    If I set up Lout, Cout, and Cboot for VCC1 3.3V output, is it correct that the VSEL Pin should be configured unconnected?
    What happens if I connect VSEL Pin to GND?

    Best Regards,
    Joonggeon

  • 0 in reply to JOONGGEON LEE
    TI__Mastermind 33440 points

    Hi Joonggeon,

    The Pin Functions table defines the VCC1 output voltage selector pin as:

    1. Connected to GND: VCC1 = 5V

    2. Floating: VCC1 = 3.3V

    (Internal pull-up of 30 kΩ)

    Best Regards,

    Jonathan