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OPA552

eli
Guru 13485 points
Other Parts Discussed in Thread: OPA552, OPA551, OPA453, OPA547, OPA452

 have design an amplifier with the OPA552FAKTWT and  have a problem with it,as it start oscillation

 have a non inverted amplifier with negative feedback ( 2 resistor )

Can you help me with that? see attached design


 

  • 0
    TI__Guru* 93105 points

    Hi Eli,

    The OPA552 is specified for closed-loop gains of 5 V/V, and higher. The gain in your circuit is about 3.5 V/V. When the OPA552 is operated in a gain less than specified their may be insufficient phase margin and the amplifier may become unstable and oscillate. Actually, that behavior would be normal.

    The OPA551 is related to the OPA552 and is unity-gain stable.  I suggest trying the OPA551 in your circuit and see if the oscillation ceases.

    Regards, Thomas

    PA - Linear Applications Engineering

  • 0 in reply to Thomas Kuehl
    Guru 13485 points

    Hi Thomas

    Thanks.

    What about using OPA547 or OPA453?

    B.regards

    Eli

  • 0 in reply to eli
    TI__Guru* 93105 points

    Hi Eli,

    The OPA453 is not unity gain stable. It is optimized for closed-loop gains of 5 V/V, and greater. You might have instability problems if you try and use it in your <5 V/V gain circuit. A very similar amplifier, the OPA452, is unity gain stable when used in gains of 1 V/V and higher. It would be a good choice providing it meets all the other electrical requirements.

    The OPA547 is unity gain stable too. However, do note that its maximum supply voltage ratings is +/-30 V and you would be operating it with the maximum supplies. That shouldn't be a problem providing the maximum isn't exceeded. The OPA547 has a 0.5 amp output current rating; 10X that of the OPA452.

    Regards, Thomas

    PA - Linear Applications Engineering