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TCA9555: Circuit review

Julian Chen
Expert 2550 points
Part Number: TCA9555


Hi E2E,

Could you kindly review the TCA9555 circuit?


  • 0
    TI__Guru* 75011 points
    Hey Julian,

    Good:
    The I2C address looks correct.
    The pin out mapping looks correct.
    Device supports 1.8V.

    potential problems:
    1) Your unused p pins are not connected to anything, internally our device uses a 100k pull up resistor so it is referenced but I need to ask, what is the end equipment? In an environment with a lot of electrical noise (industrial/power station/ect..) the 100k pull up resistors may be too weak.

    2) What is P00, P01, P02, and P03 feeding into? MUX select? I wanna make sure what ever it is, it is a high impedance input otherwise you may damage the CMOS output stages of the device (unless you are using them as inputs, then this is okay). If it is an input, please remember internally we reference the pins to a 100k pull up resistor.

    Major problems:
    Nothing apparent I can see.


    Thanks,
    -Bobby