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TCAN1042HV: Schematic Review Request

Roy Hsu
Genius 9390 points
Part Number: TCAN1042HV

Hi there,

Would you be able to review the attached schematic (the CAN Bus part) for me?

Thank you!

Best regards,

Roy Hsu

  • 0
    TI__Guru 74282 points

    Roy,

    This schematic is setup correctly. The only part I would check is the FET on the bus, making sure it doesn't add too much capacitance or propagation delay. Looking at the datasheet, it will add 50pF, which is fine, just something to keep in mind.

    One more thing, are the TXD and RXD lines connected to an MCU with internal pull ups?

    Regards,

  • 0 in reply to Eric Hackett
    TI__Genius 9390 points

    Hi Eric,

    Yes, they are connected to pull-ups.

    Another question I have is that, is there any suggested impedance value for the CANH / CANL traces?

    Thank you!

    Best regards,

    Roy Hsu

  • 0 in reply to Roy Hsu
    TI__Guru 74282 points

    Roy,

    They should be the same length, and impedance matched 120Ω differential, 60Ω single-ended. That is, with respect to GND, 60Ω should be seen on CANH and  60Ω should be seen on CANL, but differential between CANH and CANL should be 120Ω. The traces should be run parallel to each other with the same spacing in between the traces throughout, and routing should be planned in a way that will avoid crosstalk from other signals.

    Regards,