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LM2903-Q1: Current absolute maximum

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Replies: 1

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Part Number: LM2903-Q1

Hi,

In some fault, LM2903 output is shorted to 12V directly.

In this case, if output is low, there is current flow from 12V to output.

It's xxxmA.

In the datasheet, current absolute maximum is 20mA.

there is no specification for negative.

Could you let me know above condition can make IC damage?

Is there any solution for preventing IC damage? TVS or limit resistor..

Thanks.

  • Hello David,

    If the output is shorted to a positive voltage (which it looks like you are), then the output will go into current limit of around 15 to 16mA.

    It will not "damage" the output, but depending on the voltage, the power dissipation can cause the die to heat up past the abs-max limit of 150°C if multiple channels are involved.

    Worst case, 20mA * 12V = 240mW. 240mW * 119°C/W = 28°C temperature rise. Not too bad, but still not recommended. It should not be a problem if the short is brief.

    If the output is pulled negative (below ground), then damage can occur. A Schottky diode is recommended to clamp the negative voltage.

    If the output may be shorted to a supply, then a series limiting resistor or "polyfuse" PTC type thermal fuse is recommended to limit the current to less than 10mA.

    Regards,

    Paul Grohe

    TI Comparators (CMPS) Applications Group

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