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OPA4188: part stressed/damaged when outputting Isc?

Kyson Tan
Prodigy 120 points
Part Number: OPA4188

Hi,

Say I am using Vs=+/-18V and there is a short at the output when trying to output +18V. Based on Figure 9 in the datasheet, at 85C for example, the output current (or Isc) will be ~16mA and at most 15V. Since the IC does not appear to have protection such as thermal shutdown to turn itself off, (1) does this mean that it will continue to output 16mA at 15V until the short is removed? (2) would outputting Isc continuously stress or damage the part (3) does (2) still apply when all 4 amplifiers are shorted to GND such that all draw Isc at the same time?

Best

  • 0
    Guru 317090 points

    The absolute maximum ratings allow one of the four outputs to be shorted to ground continuously.

  • 0
    TI__Guru 55466 points

    HI Kyson,

    When the OPA4188 is powered with ±18V supplies, at 85C and shorting the output to GND for example, and the amplifier attempts to drive the output to +18V, the device will source a current of ~16mA.  if driving a negative voltage, the output can sink  a short circuit current of -17mA., per the specifications of Figure 9 of the datasheet.  The device will attempt to source or sink the short circuit current until the short condition is removed.

    Table 7.1 list the Absolute Maximum Ratings of the OPA4188 device. the datasheet only offers assurances that the device will be able to withstand the short circuit current continuous, on one amplifier per package without damage.

    Best Regards,

    Luis

  • 0
    TI__Guru 67611 points

    Adding to Luis reply:

    1. You are correct.

    2. In short, Isc would NOT damage the part. But keeping the part under short-circuit condition for extended period of time would shorten the expected life of the product due to high junction temperature.

    3. No. You may short only one channel at the time. - see above.