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TCA9517: Internal Pull-up Resistor Value on Enable Pin

Aditya Singh
Intellectual 280 points
Part Number: TCA9517

Hi E2E Team,

TCA9517 datasheet, function block diagram (section 9.2) shows internal pull-up on enable pin with VCCB. Please share the pull-up resistor value.

Regards,

Aditya

  • 0
    Guru 257800 points

    The EN pin has a specified worst-case leakage current of −30 µA, so the resistor is at least 177 kΩ.

  • 0
    TI__Mastermind 27173 points

    Aditya,

    Clemens is correct here. The EN pin pull-up resistor (although not specified in the datasheet) is in the 100kohm range. 177kohm is an estimate for this pull-up resistor. Most applications have an external pull-up resistor (10k) for added biasing strength. 

    If the exact pull-up resistor value is needed, it can be estimated by measuring the voltage of VCCB and the EN pin voltage, taking the difference between VCCB and EN,  and dividing it by the leakage current to estimate. This is only an estimate amount however since there is some leakage that will not be caught by this method due to the input leakage from the internal buffer drivers. 

    Regards,

    Tyler