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TPS54561-Q1: TPS54561-Q1: Disabled output - backwards powering

Jon Eirik Sternang
Prodigy 390 points
Part Number: TPS54561-Q1

Hi

If I have no voltage connected to VDD and EN is pulled to VDD (which is not connected to anything), will the device handle 5V connected to the output? Will the device draw any current from the connected 5V into the SW pin?

  • 0
    TI__Guru 64365 points
    It is not a good idea for any device to have an output voltage forced when there is no input voltage. The device may try to power on.
    More importantly, you will be forward biasing a parasitic diode inside the device. This can have unexpected consequences. If you need to operate with a forced output voltage and no input voltage you will need some kind of isolation diode.
  • 0
    TI__Mastermind 23835 points
    Hi,

    Yes i checked on bench and the part does not switch during that particular condition.
    I would recommend using a resistor divider from VDD to EN.

    Thanks
    -Arief