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SN65HVD78: Driver output in case of Vcc<0.5V

Part Number: SN65HVD78


I would like to ask you 2 questions as below, for sure.

Q1) Driver output

When Vcc is lower than 0.5V (Vcc<0.5V), the output driver is on "Hi-Z" state in case of DE is "H" (active), I think.

Is my understanding correct?

Q2) Device reliability

In case of applying 0.5V to Vcc (not 0V) normally(long time), does this condition give any damage to device when Vcc is getting ON(0.5V to 3.3V)?

Or something less reliability happened?

I think that the device will work correctly in this case, correct?

Thank you for your support.

Best Regards,


  • Takumi-san,

    In short, your understanding for both questions is correct. I just want to add a little more details for low voltage operation. To be clarify, there is no under voltage protection circuit in the device. When the power supply is too low, like 0.5V, the internal circuitry will stop working therefore the bus pins will look like Hi-Z. You may also see a little larger bus leakage current. But there is no reliability concern when Vcc is between 0.5V and 3.3V. Please let me know if you have any further question.
  • Hao-san,

    Thank you very much for your answer !

    I understood.

    Sorry for my reply as I was out of office..