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Thread: Op amp power

  1. #1
    sfink06 Newbie
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    Op amp power

    hi all,
    how could I determine how many op amps I can run off the same power supply?
    I am trying to find out how many opa548's i can run from a power supply that says it can deliver 5A max. here is the data sheet for the op amp
    http://focus.ti.com/lit/ds/symlink/opa548.pdf


  2. #2
    smanches Excellent smanches Excellent smanches Excellent smanches Excellent smanches Excellent
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    Quote Originally Posted by sfink06 View Post
    hi all,
    how could I determine how many op amps I can run off the same power supply?
    I am trying to find out how many opa548's i can run from a power supply that says it can deliver 5A max. here is the data sheet for the op amp
    http://focus.ti.com/lit/ds/symlink/opa548.pdf
    Probably a couple of hundred, but why would you want to? What is it that you are trying to do?

  3. #3
    sfink06 Newbie
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    Quote Originally Posted by smanches View Post
    Probably a couple of hundred, but why would you want to? What is it that you are trying to do?
    I am running some DC to HV-DC converters with these amplifiers, which take input voltage from a DAQ. someone mentioned that the power supply was limited to 5A, and that I should make sure that it would be able to run all 9 op-amps in the circuit at the same time. I don't know how many amps they need to draw from the power supply.

  4. #4
    smanches Excellent smanches Excellent smanches Excellent smanches Excellent smanches Excellent
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    Well, now that I look a bit closer at the datasheet, I finally see the right figure.

    Maximum continuous current output. +/- 3A.

    So less than two running at full output current.

    These are big ones.

  5. #5
    sfink06 Newbie
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    Quote Originally Posted by smanches View Post
    Well, now that I look a bit closer at the datasheet, I finally see the right figure.

    Maximum continuous current output. +/- 3A.

    So less than two running at full output current.

    These are big ones.
    for my application the the converters draw about 1.5 amps, but I was hoping that on page 3 under power supply the listing of max Q current being +/- 20 mA would mean that I could run all nine. I wouldn't know how to even start dealing with the headache of switching between amps the whole time.

  6. #6
    smanches Excellent smanches Excellent smanches Excellent smanches Excellent smanches Excellent
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    The Q current is the current that is being drawn when it is not in use, but still powered. It's the minimum current that it will draw at any time.

    Looks like you may need a bigger power supply.
    Last edited by smanches; 10th July 2009 at 06:48 PM.

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