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TPS55288: I2C function is enabled or not when Vin=0V and VCC is driving by external 5V

Ann_Lien
Genius 14460 points
Part Number: TPS55288

Hello expert,

My customer has a question that if I2C function is enabled or not when Vin=0V and VCC is driving by external 5V. May I have your help on this case? Thanks a lot!

Best regards,

Ann Lien

  • 0
    TI__Guru 65610 points

    Hello Ann-Lien,

    Section 7.3.4 in the datasheet shows the following information:

    The TPS55288 has a dual function enable and undervoltage lockout (UVLO) circuit. When the input voltage at the VIN pin is above the input UVLO rising threshold of 3 V and the EN/UVLO pin is pulled above 1.15 V but less than the enable UVLO threshold of 1.23 V, the TPS55288 is enabled but still in standby mode. The TPS55288 starts to detect the resistance between the MODE pin and ground. After that, the TPS55288 selects the power supply for VCC, the I2C slave address, and the PFM or FPWM mode for light load condition accordingly.

    So according the datasheet, no, when VIN is below 3V, the device is in shutdown and no communication is possible.