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LM4871: LM4871 volume control

jtronix
Intellectual 310 points

Part Number: LM4871

Hi,

Can someone guide me for design LM4871 based audio amplifier with volume control?

  • 0
    TI__Mastermind 20085 points
    Hello Jtronix,

    This device doesn't have a volume control system. But you could use a potentiometer to vary the amplifier's gain or add an opamp in the input to vary the input's gain.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0 in reply to José Luis
    Intellectual 310 points

    Where do I connect potentiometer?

    As per my view if i replace Rf (feedback resistor) with potentiometer then i can change output voltage but i don't whether this is preferred way to control volume.

    second way I assume that if i connect potentiometer at Bypass pin then i can able to control volume.

    please give your suggestion.

  • 0 in reply to jtronix
    TI__Mastermind 20085 points
    Jtronix,

    You are right regarding potentiometer. But I forgot to mention that you should take into account the gain level because if the gain is very high the device can get output clipping.
    It is not recommended to connect a potentiometer or another component at bypass pin because that could cause noise or poor power supply rejection.
    On the other hand, I consider that the best choice is to use an opamp.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer