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TCA9546A: For Vcc=3.3V, will the level translation work from 3.3V to 1.8V SDA/SCL is 3.3V and SD2/SC2 is 1.8V.

Farshad Farahbakhshian
Prodigy 330 points
Part Number: TCA9546A

I am planning to use TCA9546 as a I2C Mux and a level translator. 

 

For Vcc=3.3V, will the level  translation work from 3.3V to 1.8V

SDA/SCL is 3.3V and SD2/SC2 is 1.8V.

  • 0
    TI__Guru 62910 points
    Hi Farshad,

    When VCC is 3.3 V, the device's internal pass gate voltage for each channel's switch will be at about 2 V (see Figure 16 in the datasheet). This means that voltages below 2 V on either side of the switch will result in conduction between the two sides, meaning unfortunately you will observe some leakage from your 3.3-V rail to your 1.8-V rail. To prevent this, you would need to keep VCC below 3 V.

    Regards,
    Max
  • 0
    TI__Mastermind 49370 points

    Hey Farshad,

    Just to give you more information in case you were interested, a similar question was asked not too long ago:

    The answer goes into a deeper explanation of why 3.3V as Vcc will not work.

    -Bobby