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PCA9555: Is it output open drain?

Part Number: PCA9555

Hi Sir,

I plan to use PCA9555 as an smbus expander as an output signal to trigger high active, but I didn't have external pull up resistor in I/O pin,

Is it suitable for PCA9555?

Thanks

  • Hey Anne,

    "as an output signal to trigger high active"

    I'm not sure I 100% follow what you mean by trigger high active hoewever I did answer the title question and addressed the external pull up resistor below.

    "but I didn't have external pull up resistor in I/O pin,"

    PCA9555 has internal pull up resistors (100k ohm) on the I/O port pins.

    "Is it output open drain?"

    You can use this device as an "open drain" output if you switch the device from An output to an input (this lets you disable the pull down without driving high with a PFET).

    I wrote an FAQ about this here:

    -Bobby