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TCA9548A: Design request review for TCA9548A I2C connections

Meshal Abdulkareem
Prodigy 10 points

Part Number: TCA9548A

I am using eight TCA9548A multiplexers to communicate with 59 LIS3MDL sensors. Each TCA9548A has all eight downstream (low-side) I²C buses pulled up, and the upstream (high-side) bus for each multiplexer is also pulled up.

I understand that I need pull-up resistors on all eight downstream buses for each TCA9548A channels. However, I’m not sure about the upstream (high-side) I²C bus: do all eight TCA9548A devices need their own pull-up resistors on SDA and SCL, or is a single pair of pull-ups on the shared upstream bus sufficient? 

Are series protection resistors required for the A0, A1, and A2 address pins? 

 

  • +1
    TI__Expert 8095 points

    Hi Meshal,

    If all eight TCA9548As share the same SDA/SCL lanes on the high-side, you only need one pull up resistor for SDA and one for SCL.

    A0, A1, & A2 do not need series resistors - they should be connected to VCC or GND directly

    Best,
    Katy