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OPA2310: Using OP Amp to make mono signal from differential signal.

Chase Jeong
Genius 5440 points
Part Number: OPA2310

Dear TI experts,

My customer wants to make mono signal (sound) from different signal.

They found the reference from google, please see the schematic below ;

RF gain is 1. (1kohm)

Vin1 and Vin2 would be the different signal from audio codec (Cirrus Logic), and finally They can make single signal through Vout.

Do you think this would be work? And If so, Can my customer use OPA2310 for this purpose?

It is okay that you suggest other OP amp parts for this, and also good for recommend other schematic or resistor value in the schematic.

Please check this issue. Thanks.

BEst regards,

Chase

  • 0
    TI__Mastermind 23310 points

    Hi Chase,

    I think the OPA2310 could work pretty well for this application since it has pretty good THD performance. 

    Do you know what the requirements are for your system? That would help me better determine a good fit. 

    • What is the needed output current? 
    • What is the supply voltage? 
    • What is the THD spec you are wanting to reach? 

    Best Regards,

    Robert Clifton 

  • 0
    Guru 275410 points

    Which codec are you using? Its datasheet should have an example circuit.

  • 0 in reply to Clemens Ladisch
    Genius 5440 points

    Dear Robert,

    Thank you for your support. I will reply asap about your question.

    Dear Clemens,

    It is WM8960 (Cirrus Logic), and I could not find reference schematic about it.

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    Guru 275410 points

    The WM8960 speaker outputs are designed to be connected directly to the speakers. They are unfiltered class-D outputs, so when going into an opamp, you do not want to amplify the switching noise, so you must add low-pass filters with a cutoff of about 20 kHz. (See p. 86/87.)

    I suspect that the WM8960's P/N outputs are perfectly symmetrical, in which case you can simply use the P output as a single-ended signal. (You still need a low-pass filter, but an R-C circuit might suffice.)

    The WM8960 has < 0.1 % THD.
    Is the speaker supply 3.3 V or 5 V?