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ISO1541: What is pull up resistor short circuit

Vincent Chen64988
Expert 4480 points
Part Number: ISO1541

Hi Team,

In my customer's application, the SCL2 and SDA2 is pull up to VCC2(3.3V) via resistors, what if one of the resistors is short circuit(it means SCL2 or SDA2 is connected to VCC2 directly) and I2C data is in communication status, does the device have risk to get damaged?

Thanks a lot.

Vincent Chen

  • 0
    TI__Guru 55795 points
    Hi Vincent,

    If the VCC pull-up resistor gets short circuit (resistor value gets close to zero Ohm), then it doesn't cause any issue directly to device SCL or SDA pins as this voltage doesn't violate device operating conditions. But when SCL or SDA output a LOW (which can happen very often) then VCC & GND get shorted through the device. This could damage the device immediately based on power supply internal current limit.

    Hence having a pull-up resistor is necessary for current limiting and normal operation of the device. Thanks.


    Regards,
    Koteshwar Rao
  • 0 in reply to Koteshwar Rao
    TI__Expert 4480 points
    Hi Koteshwar ,

    Noted, thanks very much for the prompt response.

    Vincent Chen