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AM26LV31E: AM26LV31E input leakage to VCC and outputs when unpowered?

Andrew Morley
Prodigy 40 points
Part Number: AM26LV31E
Other Parts Discussed in Thread: AM26LV32E

The AM26LV31E is intended for use in applications when its inputs are connected to an active (driven) line even though it - and the electronics connected to its outputs - are not powered. Thus it is specified to tolerate +/-14v on those inputs even with no power, and the outputs are still guaranteed to output no more than +/-100µA. Correct me if I'm wrong in my interpretation of the data sheet.

However this raises a few questions:

  • Is Ioff the total output current for all four outputs or is it per output?
  • What is the leakage path from the inputs to the supply rail, ie what current should we expect to see driven onto the (unpowered) Vcc from a powered line.  (I am aware of the figure in section 8.2).

In short, I want to avoid the differential lines back-powering the rest of our system when it remains connected but powered-off. What amount of current to I need to expect back-powering from the AM26LV31E?

Thanks

Andrew

  • 0
    TI__Mastermind 25705 points

    Andrew,

    It's a common concern that if the device would back-power the system. The IO(OFF) spec describes the maximum 'leakage' current in this case. 100uA is per one output. The input is a logic pin, which doesn't have any direct current path to the unpowered Vcc. If you have any further questions, please let me know.

    Regards,

    Hao

  • 0 in reply to Hao L
    Prodigy 40 points

    Hao L said:

    It's a common concern that if the device would back-power the system. The IO(OFF) spec describes the maximum 'leakage' current in this case. 100uA is per one output. The input is a logic pin, which doesn't have any direct current path to the unpowered Vcc. If you have any further questions, please let me know.

    Thanks!  You've answered the question, so thank you.  Unfortunately I've just realized that I asked the wrong question. I mis-typed and should have asked about the am26lv32e (the receiver rather than the transmitter). I've corrected the question and referred to the correct device here.

    Sorry about that,

    Andrew