PCA9548A: Can I connect two more slaves on one of the output channels of this chip ?

Part Number: PCA9548A

Hello,

I am planning to use PCA9548A for connecting 8 USB type c CC controllers on this chip.

Hoping to add one more slave on each output channel in addition to CC controller, may be MCU I2C on terminal side of my device 

 

Question here is can i add 2 slaves on one of the output channel of PCA9548A?

(Assuming two different slave addresses / same voltage levels )

Thanks

ATharva

  • There is no explicit limit on the number of slaves. But section 9.2.2 of the datasheet says:

    The maximum bus capacitance for an I2C bus must not exceed 400 pF for fast-mode operation. The bus capacitance can be approximated by adding the capacitance of the PCA9548A, Cio(OFF), the capacitance of wires, connections, traces, and the capacitance of each individual slave on a given channel. If multiple channels are activated simultaneously, each of the slaves on all channels contribute to total bus capacitance.

    Three devices (master and two slaves) at a time is perfectly fine.

  • Thanks for the help Clemens!

    Atharva,

    I've notified a TI engineer of this thread to get more eyes on it.

    Regards,

    Eric Hackett 

  • Hi ATharva,

    I agree with Clemens on this. Adding more devices on the secondary channel is fine if they don't have conflicting addresses and operate on the same logic levels.

    -Bobby

  • Thanks folks.

    Clarified my doubt. Planning to use buffers to avoid drive issues.

    Thanks

    Atharva