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Original question:

PCA9306: PCA9306 Variable Vref

PCA9306: Turning off one of the Vref input for Power consumption

soe moe
Prodigy 10 points

Part Number: PCA9306

Dear Support,

I have a question on application of PCA9306. I am considering to turn off on the Vref2 to save the power as the application uses only a battery and device may draw up to 20+ mA.

The main bus is on 3.3V and Vref2 is 5V. If Vref2 is set to "0" will there be high leakage current from the Vref1 to the i2C device on the Vref2 side?.

Regards,
Moe 

  • 0
    TI__Guru 53535 points

    Hi Moe,

    The leakage current from Vref1 while Vref2 is disabled (0v) will depend on the state of the EN pin. If this pin is common with Vref2, then the device will be disabled when this rail is low and you will see minimal leakage in this configuration. If this is not the case and EN remains high while Vref2 is disabled, a leakage path between Vref1 and Vref2 will exist through the 200k-ohm resistor which will limit this current to 165uA when Vref1 is 3.3v (and no resistance is provided to ground from Vref2. Actual leakage will be less) In either case, please ensure the 200k-ohm resistor is present between your 5v rail and Vref2.

    Let me know if this answers your question or if you'd like to know anything else.

    Regards,
    Eric