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TPS54320: TPS54320 the EN pin input signal

Allen1
Prodigy 120 points
Part Number: TPS54320

Hi ,

I have a question about TPS54320.

Now, I want to controll the EN pin by the external signal.

Datasheet say if an application requires controlling the EN pin, use an open-drain output logic to interface with the EN pin.

Can we input High/Low signal directly to the EN pin?
Is the EN pin required a external pull down resistor ?

  • 0
    TI__Mastermind 35165 points

    It is ok to drive the EN pin directly with a high/low signal. You may need a pull down resistor but it depends on the characteristics of what you plan to drive the pin with and the desired behavior.

    The EN pin has an internal current source of ~1 µA which will pull up the pin if it is left floating. This is why the datasheet mentions driving it with an open-drain logic signal. Open-drain logic would be able to pull EN low to disable the part. When the open-drain logic goes high-impedance, the internal current source pulls up the EN pin to enable the TPS54320.

    If you want to make sure the part is only enabled by your high/low signal and you cannot guarantee what is generating the signal to drive EN will always have drive capability to pull EN down, I suggest adding a 100 kΩ pull-down resistor.