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OPA548 output impedance

Pol REYMOND
Intellectual 1830 points
Other Parts Discussed in Thread: OPA548

Hi team,

In order to realize a stability study, my customer would like to know if you have more details about the output impedance for the OPA548.

Thanks for your help.

Pol

  • 0
    TI__Guru* 93105 points

    Hi Pol,

    Please see the attached OPA548 TINA file. The OPA548 TINA model has been modified to better mtach the approximate open-loop Zo vs frequency characteristic. The open-loop gain/phase  vs frequency was tested and closely matches the datasheet.

    Regards, Thomas

    PA - Linear Applications EngineeringOPA548 TG_Zo.TSC

  • 0 in reply to Thomas Kuehl
    TI__Intellectual 1830 points
    Hi Thomas,

    Is it right for the full temperature range and the full load scale?

    Thanks for your help
  • 0 in reply to Pol REYMOND
    TI__Guru* 93105 points

    Hi Pol,

    The op amp system interface that is used to measure Zo does not lend itself to being drfited across temperature; therefore, the curve is taken at room temperature. Our experience has been that when the measured Zo curve information is applied in an actual circuit, and compensation applied if needed, the circuit is stable over temperature.

    The measurment is made with the output lightly loaded which is the low operating current case. That is almost always the worst case Zo condition for an op amp because it is in its highest impedance condition. Increasing the load current decreases both R and +/-jX moving the Zo down and closer to the 0-Ohm level we would like to have.

    Regards, Thomas

    PA - Applications Engineering