TPA3126D2: Volume Control

Frank Mancuso

Part Number: TPA3126D2

Hello, I am developing a standalone audio power amplifier using the TPA3126D2. The input to the amplifier will be a typical audio DAC with single-ended output. I would like to add a volume control (i.e. ganged potentiometer) to the input of the TPA3126D2 amplifier.

Can you provide some circuit suggestions on how to add the audio potentiometer to the TPA3126D2 input to ensure the audio amplifier fidelity is not compromised? Please also provide maximum potentiometer resistance value as well. Thanks!

over 4 years ago

0 Yanming Gong over 4 years ago

TI__Mastermind 19010 points

Hi Frank,

Do you want to limit the AMP output? If so, TPA3126 has PLIMIT pin and the feature to limit the output, you can refer the 8.3.4 part in datasheet.

The internal input impedance is 7.3Kohm @36dB. If you want to add resistors on input, I suggest the resistors is not larger than 1Kohm.

Regards,

Derek

0 Frank Mancuso over 4 years ago in reply to Yanming Gong

Prodigy 70 points

No, I don't want to limit the output.

I basically want to add a volume control to the amplifier. From your response, it sounds like I should follow the potentiometer with an op-amp buffer to provide low impedance but that will increase the cost. Do you have an application circuit that implements volume control on the TPA3126D2 or similar amplifer?

0 Yanming Gong over 4 years ago in reply to Frank Mancuso

TI__Mastermind 19010 points

Hi Frank,

Sorry, I do not have other recommend volume control circuit in fact.

Regards,

Derek

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TPA3126D2: Volume Control