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OPA549: Single Supply Power Amplifier

Eui-Heon Jung
Expert 1085 points
Part Number: OPA549
Other Parts Discussed in Thread: OPA593, , OPA541

Dear Team,

I want to make single supply power amplifier.  The given conditions are as follows.

1. Input Signal : From AD5932 (Programmable Frequency Scan Waveform Generator)

    - Peak to Peak : 0.58V (Internal 200ohm resistor to GND)

    - Voltage at midscale output : 0.32V

    - Minimum Voltage : 56mV

2. Wanted Output Voltage  : 0 ~ 24V ( If it is not possible, please let me know the allowable range.)

3. Wanted Output Frequency :250KHz ( If it is not possible, please let me know the allowable range. )

Please recommend a circuit that can be implemented.

Sincerely,

Eui-heon

  • 0
    Expert 1085 points

    I'm Sorry, The output frequency is 25kHz.

  • 0
    Guru 258280 points

    This is not a rail-to-rail opamp.

    What supply do you have?

    What output current do you need?

  • 0
    Guru 140200 points

    Hi Eui-heon,

    Eui-Heon Jung said:
    I want to make single supply power amplifier.

    But with a single supply power amplifier you have to shift the output signal of OPAmp by a DC offset of about middsupply (pseudo ground) to prevent the output signal from going into saturation. Is this what you plan?

    And how do you want to transfer the output signal to the following circuitry? Superimposed to the pseudo ground potential? Or by AC coupling with the help of a suited RC high pass filter?

    Kai

  • 0 in reply to Eui-Heon Jung
    TI__Guru 51511 points

    Hi Eui_Heon,

    Per comments from Clemens and Kai, please provide the missing design requirements for your application. 

    Without knowing the details of your requirements, I am taking a wild guess what you may want. If the output sourcing current is >250mA, then OPA593 will not applicable for the design. This is just an example. 

    OPA593 Driver 07202022.TSC

    If you have additional questions, please let us know. 

    Best,

    Raymond

  • 0 in reply to Raymond Zhang1
    Expert 1085 points

    Dear Raymond,

    Thank you for your reply. The desired current output is 5A. If I apply dual supply, can I get the desired output? If OPA549 is not applicable, is there any solution that satisfies my condition?

    Sincerely,

    Eui-heon

  • +1 in reply to Eui-Heon Jung
    Guru 258280 points

    An output voltage of 0 V with a single supply would require an infinitely low resistance. This is not possible.

    For 5 A, the only choices are OPA549 or OPA541 (or building an amplifier stage from discrete components).

    The OPA541's output requires 5.5 V headroom to the supply rails.
    The OPA549's output requires 4 V headroom to the positive and 3.2 V headroom to the negative supply rail.

    Please note that the power that is not dissipated in the load is dissipated in the opamp, so you need very good cooling.