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Please, help-me to find an OPA

Other Parts Discussed in Thread: THS4032, THS4012, THS4022, THS4082

It seeems the tool does not work very much.

I need, for an audio output of a DAC an OPA with the followings

Double 8-Pin SOIC

Voltage feedback

Unity gain stable

rails >= +- 15V

High slew rate (>100V/µs)

High output current (>= 50ma)

Low noise (<10nv/µs)

Thanks for your help.

  • Based on your needs, there are two recommendations off the top of my head:

    a) THS4032 - lowest noise

    b) THS4012 - more speed and bandwidth at the expense of a bit more noise than the THS4032, but is <10nV/rtHz

    Cheers,

    Randy

  • Hello Christophe,

    Also the THS4022 and THS4082.

    However, you mentioned Audio DAC.

    I'm guessing you are trying to use a high speed device in order to get faster settling, lower distortion or slewing.

    Be careful using high speed op-amps if you are concerned about noise in the audio band.

    The 1/f noise of high speed devices can be higher than that of the lower speed devices at low frequencies. Be sure to compare the noise spectrum plots of lower speed "low noise" devices you might be considering (both voltage noise and current noise). You may find that a "nosier" low speed part is actually lower noise than a high speed device throughout the audio band (10Hz to 30KHz) in your circuit.

    They are also more sensitive to output capacitance and may oscillate with high impedance loads.

    High speed devices can also have lower open loop gain, so their distortion performance at low frequencies may be worse than a "precision" or "low distortion audio" lower frequency device.

    Just be aware of these issues and double-check that the circuit is performing as you are expecting (double check for ringing, settling, distortion and excess noise).

    Regards,

  • Thank-you very much. Perfect !

  • Thank-you, ,Paul.

    Of course, i know, but i worry more about TIM and FM distortion than noise or numbers.

    By habit, i am used to current feedback devices, but here, i need a symmetrical input.