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SN65HVDA1050A-Q1

Joey Christ
Intellectual 2260 points

If the SN65HVDA1050AQDRQ1 has no Vcc, no signal o nTXD, Vref=open, and a signal is a signal on CANH & CANL, what is the behavior of the part?

Can these conditions damage the part?

  • 0
    TI__Expert 3360 points

    Hi Joey,

     

    I have notified the application engineer responsible for this device.

     

    Best regards

    David Xu

  • 0 in reply to David Xu1
    TI__Mastermind 21326 points

    Hi Joey,

    The CAN and LIN transceivers are all covered by the Industrial Interface group. I am therefore going to move you post to the correct forum so it can get the proper visibility and support.

    Thanks,

    John

  • 0 in reply to John Griffith
    TI__Mastermind 21326 points

    Hi Joey,

    The device will add some loading to the bus (both differential and single ended with respect to ground), but it will not block communication.

    I took one device in the lab and measured the differential resistance (from CANH to CANL) as ~52.5kΩ (using a source meter with 10µA of current). I then measured the single ended resistance from both CANH and CANL with 10µA of current and got 113.54kΩ and 113.52kΩ. To show a more realistic loading that would occur with the common mode voltage of 2.5 volts the CAN has, I then sourced 2.5 volts on both CANH and CANL and measured the leakage current to calculate the input impedance. I got ~57.05µA for both CANH and CANL. This computes to an input resistance of ~44kΩ. This "resistance" measurement will continue to drop as the voltage increases since the protection diodes will begin to leak more and more.  

    Therefore, as you can see the unpowered floating device will place a load on the bus, but it will not interfere with communication unless 10's of these nodes are placed in parallel.

    Thanks,

    John