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Opa547 datasheet questions

  1. Mar 5, 2009 #1
    So if we have a Opamp component, do we have to give the input as sine wave or as a dc supply? I think it has to be at a DC voltage. please correct me.
    Thanks in Advance
  2. jcsd
  3. Mar 6, 2009 #2
    Re: Opa547

    Most opamps will amplify a sinusoidal or dc signal.
  4. Mar 6, 2009 #3
    Re: Opa547

    So I can get a constant OUTPUT DC current with this opamp rt?
  5. Mar 6, 2009 #4
    Reading a datasheet

    Hi I need to understand few things about the Datasheet. I want to know what the input voltages for the pins vIN+ and VIN-could be. Please find teh enclosed datasheet for reference. I need it very urgently for a project.
    Thank you in advance

    Attached Files:

  6. Mar 6, 2009 #5


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    Re: Reading a datasheet

    Look at the item marked "common mode voltage range" in the datasheet.
  7. Mar 6, 2009 #6
    Re: Reading a datasheet

    I reffered to it but, what do they mean by saying the following there? (V+) –3
  8. Mar 6, 2009 #7


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    Staff: Mentor

    (I merged the two related threads into one -- both were about the opamp datasheet)
  9. Mar 6, 2009 #8


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    If you mean V+ or V-, those should be DC voltage supplies.

    If you mean V+IN and V-IN, it could be either AC or DC ... depends on the application.

    (Refering to figure on p. 1 of the datasheet:
    https://www.physicsforums.com/attachment.php?attachmentid=17873&d=1236355902 )
  10. Mar 6, 2009 #9
    i really dont understand why they are on the same subject. one is about the circuit the other is about reading the data sheet for the component.

    << post edited by berkeman to clean up txt speak >>
    Last edited by a moderator: Mar 6, 2009
  11. Mar 6, 2009 #10
    Re: Reading a datasheet

    ideally, you want an op-amp to amplify only the difference between Vin+ and Vin-, not to amplify the average of Vin+ and Vin-. the higher the common mode rejection ratio, the closer you are to this ideal. to get the best rated performance for this op-amp, keep the inputs between (V-) - 0.1, and (V+) -3V.
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