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TDA4VE-Q1: can we change I2C pu power rails?

Xingyu Zhu
Expert 4335 points
Part Number: TDA4VE-Q1


Dear expert,

Our customer find the power rail VSYS_IO_3V3 may leakage to external device through I2C PU resistor. They want to change the PU rail to other rails from external device to avoid leakage risk. Could you help to check if there is any risk of that? Thanks.

Best Regards,

Xingyu Zhu

  • 0
    TI__Guru 53045 points

    The I2C pull-up resistors should be connected to same rail which powers the IO (VDDSHVx).  Based on brief description, it is unclear on this specific issue.  IO should not have power prior to VDDSVHx power pin, else leakage can occur. 

  • 0 in reply to Robert Eschler
    TI__Expert 4335 points

    Hi Robert,

    Thanks for your reply. Understood. We recommend to use same rail of IO and using the power prior can cause leakage. But our customer find if use the same rail powering the IO, this rail may leakage to the other device communicating with TDA4 via I2C, because TDA4 is powered earlier than the other device. So they want to change the default rail to other rail which comes later to avoid leakage. Do you think it is OK? Thanks.

  • 0 in reply to Xingyu Zhu
    TI__Guru 53045 points

    To avoid leakage in both devices, recommended inserting a passive buffer on the I2C signals between the SOC and other peripheral. Select a passive buffer that supports Ioff feature - Ioff does not allow leakage on its IO when power is OFF.  Many of TI's passive buffers support this feature.  Power the buffer from the supply which comes up LAST.