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ISO7741-Q1: leakage and clamping currents

Matthias Geipel
Prodigy 120 points
Part Number: ISO7741-Q1


Tool/software:

Hello experts,

I have some questions concerning the ISO774x-Q1:

  1. What is the maximum output leakage current of a disabled output OUTx? Is it below 1µA, in the range of 10µA or is ist higher? I couldn't find this in the datasheet.
  2. The input leakage currents of the ENx inputs have been updated in datasheet revision G (SLLSEU0G from October 2024). They have been increased to +/-20µA for 5V supply, but to +/-30µA for 3.3V and 2.5V supply. That's strange to me. I would have expected a higher leakage current at higher supply voltage. So should I also assume +/-30µA for 5V supply? Or are the datasheet values really correct?
  3. In case there is no current limitation, the input voltage should be limited to -0.5V ... VCCI + 0.5V according to abs. max. ratings. As the inputs provide internal protection diodes towards GND and VCCI, it should be okay to limit the input current instead of the input voltage. What is the maximum input clamping current that the ISO774x-Q1 can safely handle? Is it okay to limit the current to +/-10mA per input? I couldn't find this in the datasheet.

Thank you,

Matthias

  • 0
    TI__Mastermind 18525 points

    Hi Matthias,

    Thanks for reaching out.

    Matthias Geipel said:
    What is the maximum output leakage current of a disabled output OUTx? Is it below 1µA, in the range of 10µA or is ist higher? I couldn't find this in the datasheet.

    This is not specified, therefore not quoted. We currently do not have the data for this.

    Matthias Geipel said:
    The input leakage currents of the ENx inputs have been updated in datasheet revision G (SLLSEU0G from October 2024). They have been increased to +/-20µA for 5V supply, but to +/-30µA for 3.3V and 2.5V supply. That's strange to me. I would have expected a higher leakage current at higher supply voltage. So should I also assume +/-30µA for 5V supply? Or are the datasheet values really correct?

    Datasheet does have the correct values.

    Matthias Geipel said:
    In case there is no current limitation, the input voltage should be limited to -0.5V ... VCCI + 0.5V according to abs. max. ratings. As the inputs provide internal protection diodes towards GND and VCCI, it should be okay to limit the input current instead of the input voltage. What is the maximum input clamping current that the ISO774x-Q1 can safely handle? Is it okay to limit the current to +/-10mA per input? I couldn't find this in the datasheet.

    The ESD diodes that are included in the input of the device are specifically meant for protecting against transients that device experiences. These diodes are not places in series to the input pin, therefore not meant for continuous driven current. The voltage definitely has to be limited according to the absolute maximum ratings. We highly encourage that you operate within the recommended operating procedures and stay within the absolute maximum ratings. TI cannot guarantee the performance/survival of the device if abs max ratings are violated. Additionally, TI warranty will be voided as well.

    Regards,
    Aaditya Vittal