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PCA9548A: Tri-State

KKF
Expert 4455 points
Part Number: PCA9548A

Hi,

What if we connected two PCA9548A and parallel the outputs, but pull RESET to one of the PCA9548A. Will it tri-state the outputs? The datasheet is not clear on this one. “When this signal is asserted low for a minimum of tWL, the PCA9548A resets its registers and I2C state machine and deselects all channels.” I understand it’s not the intended purpose of the RESET pin to keep it low, but would it work?

Thanks,
KF

  • 0
    TI__Guru 72751 points

    Hello KF,

    I would first like to recommend using the TCA version of this device as it addresses some bugs the PCA family had, is pin to pin compatible, typically supports wider Vcc ranges, and is usually more cost competitive.

    Now if you drive the reset pin low, the device's channels would no longer be selected (disabled) which would make the reset PCA9548A high impedance (tri state as you put it). You could drive the reset signal high again and the device would remain in high impedance until you address its internal registers once again.

    Thanks,

    -Bobby