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Need an op amp can sink 2A current

David Zhang16358
Expert 1860 points
Other Parts Discussed in Thread: OPA548

Can OPA548 sink 2A current?

Thanks.

  • 0
    Guru 21975 points

    David,

    Yes, the OPA548 can sink 2A.  With load currents you must be mindful of the power dissipation in the op amp. The combination of voltage across the conducting transistor in op amp and the load current determines this dissipation. You must provide sufficient heat sinking to keep operating temperature within acceptable limits. For more information, check out this applications note:

    http://www.ti.com/litv/pdf/sboa022

    Regards, Bruce.

     

     

  • 0 in reply to Bruce Trump
    Expert 1860 points

    Just a curious question:

    Please check the attached picture.

    If the load generated 2A current source then this 2A current could be sinking by OPA548?

    Many sincere thanks.

  • 0 in reply to David Zhang16358
    Guru 21975 points

    David,

    I'm not sure I understand your question but let me try this explanation:

    The OPA548 is capable of sinking 2A if its input signal and feedback loop is driving it to do so. If the load is forcing it to sink 2A and its input or feedback is not driven to sink this current, the output voltage would increase, attempting to "not accept" the current that is forced upon it. If the load can create a voltage that is greater than the supply voltage of the op amp, it could damage the op amp. A clamp diode from output to power supply would help prevent this.

    Regards, Bruce.

  • 0 in reply to Bruce Trump
    Expert 1860 points

    I am confused by how to drive OPA548 to sink current by its input and feedback loop.

    If it is possible, please show me a sample example.

    Many Thanks.

  • 0 in reply to David Zhang16358
    Guru 21975 points

    David,

    Please explain your application. What do you want to op amp to do? What is the input signal? What is the load?

    Regards, Bruce.

  • 0 in reply to Bruce Trump
    Expert 1860 points

    I want to find an op amp, this op amp should not only sink 2A current but also can generate DC output voltage from +2V to +15V.

    Please check the attached PDF file.

     It explains the load connected to this op amp and shows the same power tap operating at two different conditions.

    At condition 1:

    The power tap is connected to +2V to +15V and source 2A current and the output impedance is low.

    At condition 2:

    The power tap is connected to +15V and sink 2A current.

    Sincere thanks.

    5270.DOC.PDF

     

  • 0 in reply to David Zhang16358
    Guru 21975 points

    David,

    If the op amp is connected to provide a voltage output it will sink or source current to the load to maintain its output voltage. The maximum current, sourcing or sinking, will be according to programmed current limit for the op amp.

    Regards, Bruce.

  • 0 in reply to Bruce Trump
    Expert 1860 points

    Thank you for your answer.

    But I am still confusing how to drive OPA548 to sink current by its input and feedback loop.

    Many Thanks.