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TCA9416: Current leakage through pull-up resistor?

Kei Kuwahara
Expert 5740 points
Part Number: TCA9416
Other Parts Discussed in Thread: TCA39306, PCA9306

Hello team,

My customer is concerned that there might be current leakage from VCCA to VCCB when VCCB is 0V.

Is there going to be any leakage current path like on the figure below?

Best Regards,
Kei Kuwahara

  • 0
    TI__Mastermind 30543 points

    Hi Kei,

    From the description in the datasheet:

    Disabling TCA9416 when VCCA and VCCB are powered disables the one-shots and internal passFETs. Internal pullup resistors are still ON. 

    Pull up resistors are individually gated by the supply voltage for each respective side. When the supply is above UVLO, the pull-up resistor for that specific side (A vs. B) is enabled. When the supply is below UVLO, the pull-up resistor for that specific side (A vs. B) is disabled. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    TI__Expert 5740 points

    Hi Tyler-san,

    Thank you for the explaination.

    How about when VCCB becomes 3.3V to 0V during operation? Will it go UVLO?
    My customer is concerned VCCB might not go below UVLO because of internal pull-up.

    Is there any I2C level shifter without internal pull up?

    Best Regards,
    Kei Kuwahara

  • 0 in reply to Kei Kuwahara
    TI__Mastermind 30543 points

    Hi Kei,

    Kei Kuwahara said:
    How about when VCCB becomes 3.3V to 0V during operation? Will it go UVLO?
    My customer is concerned VCCB might not go below UVLO because of internal pull-up.

    VUVLO_FALL = Under Voltage Lockout Falling Threshold would be the spec to look at when VCCB goes from 3.3V to 0V. When VCCB < 0.6V, we can always expect an UVLO condition, and therefore the internal pull-ups to be disabled. 

    If the customer cannot pull VCCB < 0.6V, then the pull-up resistors internal to the device will not be disabled. 

    Kei Kuwahara said:
    Is there any I2C level shifter without internal pull up?

    Yes. TCA39306/PCA9306. These are passive level shifters with no internal pull-ups to the device. 

    Regards,

    Tyler