TPA6120A2: Load Parallel TPA6120A2

Part Number: TPA6120A2

Tool/software:

I am using two TPA6120A2 amplifiers, each receiving different audio input signals, and connecting their outputs to a common headphone. However, I am experiencing an issue where the headphone output signal fluctuates, causing irregular volume levels (alternating between high and low). Could someone help identify the cause or suggest a solution?

  • Hello Sumathi,

    I can review this behavior for you.  

    Can you confirm the top amplifier is doing differential input to differential output amplification?  It appears the bottom amplifier is being used in a single-ended input to single-ended output.  

    There may be circuit changes necessary to drive the same headphone with both stereo (top amp) and mono (L channel bottom amplifier). 
    Are you using only one amplifier at a time?

    Best,

    Alec

  • Hi Alec,

    Thanks for the response.

    In the top amplifier, there are two single-ended inputs and two single-ended outputs. One of the single-ended inputs is connected to the Left op-amp, while the other is connected to the Right op-amp.

    All amplifiers are utilized at a time, sometimes only one amplifier is in use. Note that all the amplifiers are single-ended audio inputs and audio outputs.

    Thank You,

    Sumathi

  • Hello Sumathi,

    This may be an issue in the impedance seen by each amplifier.  Are the output voltage fluctuations repeatable, consistent, or random?

    Best,

    Alec

  • Hi Alec,

    the output voltage fluctuations are repeatable and sometimes it will be consistent while doing testing.

    Thank You,

    Sumathi K