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OPA1622: EN input current

Alexander Feldengut
Prodigy 230 points
Part Number: OPA1622

Hello,

the typical EN pin input current for +25°C is given in the datasheet with 1.5 uA. Please specify the maximum input current considering the temperature range -40..125 °C.

Is the input current caused by a pull-up or a pull-down resistor or something else?

Regards, Alexander

  • 0
    TI__Mastermind 23935 points

    Hey Alexander, 

    We are unable to provide a max specification outside of our product datasheet. We do not have data for this pin over temperature. The simplified internal schematic is shown below for the enable pin. 

  • 0 in reply to Chris Featherstone
    Prodigy 230 points

    Hi Chris,

    is it possible to give a rough estimation for the maximum value, e.g. 10 times the typical value.

    Regards, Alexander

  • 0 in reply to Alexander Feldengut
    TI__Mastermind 23935 points

    Hey Alexander, 

    When the enable voltage is high the current will mainly flow through the diodes as shown below. At T = 125 C we can assume 0.5 V across the diodes. The 500k resistor can vary by 20 % and therefore I took the worst case for my calculation and assumed it decreased by 20 %. This gives the estimated 11.25 uA when the enable voltage is at 5 V. The current will vary depending on the enable voltage. 

    I hope this helps. Let me know if I can be of further assistance.

    Best Regards, 

    Chris Featherstone

  • 0 in reply to Chris Featherstone
    Prodigy 230 points

    Hello Chris,

    thank you very much for the detailed explanation.

    Please provide also the estimation when the enable voltage is 0 V.

    Best Regards, Alexander

    PS: Should the % character be removed from the formula?

  • 0 in reply to Alexander Feldengut
    TI__Mastermind 23935 points

    Hey Alexander, 

    Please see the corrected slide below that removes the % and also corrects for the two diode potentials at hot temps. Specifically the potential across two diodes at hot should be 1 V. 

    Here is the additional example showing the calculation for estimating the current when Ven < 1.4 V. 

    Best Regards, 

    Chris Featherstone

  • 0 in reply to Chris Featherstone
    Prodigy 230 points

    Hello Chris,

    so the leakage current from the diodes between the supply pins and the enable signal, for example between VCC (5 V) and EN (0 V), can be neglected.

    Best Regards, Alexander

  • 0 in reply to Alexander Feldengut
    TI__Mastermind 23935 points

    Hey Alexander, 

    Approximately 5 nA at T = 125 C can be assumed for the diode leakage. This current doubles every 10 degrees C and is much lower for room temperature. For room temperature this current may be ignored. For hot temperatures this current should be added to the previous approximation. 

    Best Regards, 

    Chris Featherstone