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SN74AUC1G00: can I pull up the output

adomino
Intellectual 1000 points
Part Number: SN74AUC1G00

Will I run into any problems if I pull the output up to 1.8V? (even though it is not open drain)

Vcc is 1.05V

  • 0
    Guru 243810 points
    Footnote 2 of the absolute maximum ratings table allows higher voltages as long as you do not exceed the output clamp current rating. So the pull-up resistor must be large enoug to limit the current from the 1.8 V supply to Vcc to less than 50 mA.

    The recommended operating conditions table says that the output voltage must not go above Vcc. So while the device will not get damaged, it might not work. In practice, it will work as long as the Vcc supply is able to sink the current.
  • 0
    TI__Guru* 96591 points

    Would you consider putting a blocking diode at the output of the device? You could (in essence) turn the device into an open-drain part by preventing the part from sourcing current (only allow sinking current, like an open-drain device). A schottky diode would add minimal delay and voltage drop.

    This is incorrect, as Clemens pointed out.  I have done this before with devices that don't have clamp diodes, but it won't work for this one - I should have thought it through a little more.

  • 0 in reply to Emrys Maier
    Guru 243810 points

    Emrys Maier said:
    Would you consider putting a blocking diode at the output of the device? … only allow sinking current

    But sinking current from the higher voltage into VCC is the problem.

  • 0 in reply to Clemens Ladisch
    TI__Guru* 96591 points

    Now that I think more about it, that was a silly idea. Thanks Clemens.

    Putting the diode at Vcc might do it though - prevent current backflow into the supply rail.