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TCA9555: One I2C bus to support 512 GPIO application

[FAE] Andrew Wang
Genius 10685 points
Part Number: TCA9555
Other Parts Discussed in Thread: TCA6424A, TCA9548A, TCA9546A

Hi Team,

My customer is looking for a solution to control total 512 GPIOs using I2C bus, unfortunately only one I2C bus is available.

And the application is to control 5V RELAY, therefore, +/-20mA clamp on each pin is necessary for handling inductive load, also simultaneous output control (as many CH as possible) is needed. Any solution in TI? 

Thanks a lot!

Andrew

  • 0
    TI__Guru 73591 points
    Hey Andrew,

    The IO expander solution we would probably want to look at is an 24 bit expander, TCA6424A.

    This device only has 2 available addresses so we would need to pair this with an I2C switch.

    512/24 = 22.

    2 unique addresses means we can have 2 devices per I2C channels, this means we need 11 I2C switching channels.
    For this, we would probably want to use an 8 channel and a 4 channel: thus we would recommend TCA9548A and TCA9546A.
    ----------------------
    "+/-20mA clamp on each pin is necessary for handling inductive load"
    You would need to add a current limitor (resistor) or something externally to clamp the current, none of our IO expanders have a current clamping feature.

    "also simultaneous output control (as many CH as possible) is needed"
    This solution would allow for you to change 24 outputs at a single time.

    Thanks,
    -Bobby
  • 0 in reply to BOBBY
    TI__Genius 10685 points

    Hi Bobby,

    Thank you so much for detail explain!

    Andrew