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TCA39306: Ask for Switch Configuration

Part Number: TCA39306
Other Parts Discussed in Thread: SN74LVC2G66, SN74AUC2G66

Dear TI Team,

I want to perform switching between I2C devices at the same voltage level of different types.

When using the TCA39306 for I2C switching, is it possible to achieve switching with the connection shown in the figure?

Best Regards 


  • This circuit will work. (In the switch configuration, only the voltage at EN matters. No current will flow between Vref1 and Vref2, so the 200 kΩ resistor and the Vref1/2 connections are not necessary.)

    A plain switch like the SN74LVC2G66/SN74AUC2G66 would be simpler and cheaper.

  • Hi Naoki,

    The TCA39306 is being used in switch configuration mode in this specific setup. Voltages are the same, so there is no current flowing from VREF2 to VREF1 as suggested by Clemens. 

    This setup should work, EN = 1.8V which will set the gate voltage of the internal passFET to 1.8v. 



  • Dear Clemens and  Tyler,

    Thank you both for your responses.

    I will use this diagram as a basis for further study of the circuit.

    Best Regards,