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PCA9548A: Question about PCA9548A functionality

Part Number: PCA9548A
Other Parts Discussed in Thread: CD4097B, SN74LV4051A

Tool/software:

Hi Team,

I will be using PCA9548A on my PCB. I would like to ask you if this IC can work as follow:

  1. Normal operation as I2C mux: I2C master unit and x5 I2C slave units with pull-up resistors connected on both sides to 3.3V




  2. Special operation as a digital MUX:

    • Phase 1. During this phase we program PCA9548A via I2C master and disconnect the pull-up resistors (slave side) via a switch



    • Phase 2. Once programmed, we switch (via a mux) from I2C master unit to a device that doesn't communicate via I2C and requires digital lines without any pull-up resistor.




Do you think this device can work in these conditions?

Thanks for your support,
BR

Roberto

  • Hello Roberto,

    I do not think this is the right device for the second part of your question.

    This device is designed for I2C communication and I2C standard communication requires pull up resistors on both sides.

    Please let me know if you need any further assistance.

    Regards,

    Kameron

  • Hi Kameron,

    thanks for your reply.

    Can you kindly recommend me an alternative P/N that can support I2C and other two-line digital protocols (3.3V logic)? Do you think I should use an analog multiplexer (eg. CD4097B)?

    BR,
    Roberto

  • Hi Roberto,

    I actually do think a analog multiplexer would be good to look into using here. I suggest you use  2x SN74LV4051A devices. This device  can support 3.3V supply and 3.3V IO signals.

    In addition it has a typical con of 23.4 pf which is good for I2C applications.

    Please let me know if this something you would be interested in using and I can help further if needed

    Regards,

    Kameron