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Original question:

PCA9306-Q1: PCA9306-Q1 for I2C signal isolation

PCA9306: Using PCA9306 for multi-controller I2C switching as well as level conversion

Richard Newell
Prodigy 10 points
Part Number: PCA9306


We have a requirement to address an EEPROM from two different controllers (one at a time). One controller operates at 3.3V. The other controller and EEPROM operate at 2.5V.

Would the attached circuit be the correct way to configure the PCA9306 to provide level conversion and to toggle between the two controllers?

Thanks

Richard

PCA9306 Multi-controller2.png

  • 0
    TI__Guru 54158 points

    Hi Richard,

    Please allow me to get back to you tomorrow morning. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    TI__Guru 54158 points

    Hi Richard,

    This implementation looks like it would work. 

    When the EC-EC-PHY signal is HIGH = 3.3V, this is supplying the VCC2 signal to U2. 

    Q2 turns on since 3.3V > VTH of the FET. The FET pulls LOW on EN of U4, disabling the device. 

    When EC-EC-PHY = LOW = 0 V, U2's EN pin will be 0V and high-z the device. 

    LOW on the gate of Q2 FET will turn it OFF, then U4 is enabled since there is no leakage path to GND on the EN pin of this device. 

    This implementation looks like a single GPIO can be used to toggle two PCA9306 in opposite fashion. Only one PCA9306 ON at a single time. 

    Regards,

    Tyler