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TCA9548A: Unpowered outputs - leakage path?

Steve Widener
Genius 11010 points
Part Number: TCA9548A

I have a question about the TCA9548, particularly about the last paragraph of the datasheet section 8.1

I will be operating the part from +3.3V_A.  The first four channels will have pull-up to +3.3V_A.  I will have another channel pulled up the +3.3V_B and another to +3.3V_C.  There will be times when the  +3.3V_B and +3.3V_C will be powered off.  If I read the last paragraph, this would be OK.  Also, the TCA9548 will not feed any voltage out to the +3.3V_B and +3.3V_C rails.  Can you confirm this?

  • +1
    TI__Guru 72161 points

    Hi Steve,

    As long as the secondary channels on the +3.3V_B and +3.3V_C are not enabled when they are powered off then there shouldn't be any leakage into those channels (you would need to have the device powered and programmed it to enable those secondary channels for a problem to occur.)

    Steve Widener said:
    Also, the TCA9548 will not feed any voltage out to the +3.3V_B and +3.3V_C rails.  Can you confirm this?

    Correct. Those rails would not see the voltages on the other channels (or leakage current into them) as long as the secondary channels to those rails are not enabled.

    -Bobby