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I am planning to take the audio aux signal of a raspberry pi and amplify it with a TPA2012D2 by Texas Instruments. In the datasheet there is a typical application circuit, which would match my needs (single ended input signal). Except I am not sure that the aux output is DAC or CODEC. Can someone explain to me if this would work?

I added a image of the typical application circuit below.

enter image description here

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  • \$\begingroup\$ Yes the audio out from R-Pi comes from a DAC so you can just connect it as shown here. \$\endgroup\$ – Brian Drummond Jan 12 '18 at 21:46
  • \$\begingroup\$ I am curious, what a CODEC stands for? \$\endgroup\$ – Marko Buršič Jan 12 '18 at 21:50
  • \$\begingroup\$ Me too. Wasn't specified in the datasheet - searched for it. \$\endgroup\$ – sarahlisa Jan 12 '18 at 21:51
  • \$\begingroup\$ @Marko COder DECoder. \$\endgroup\$ – winny Jan 12 '18 at 21:53
  • \$\begingroup\$ @winny But what does it output? An analog signal? Or coded signal with some modulation? \$\endgroup\$ – Marko Buršič Jan 12 '18 at 21:57
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This amp IC accepts analog audio input. You must have it. Obviously your audio output is analog. Text DAC or Codec refers to your case. If your audio is generated by computer software, it must be an output from a DAC (=digital to analog converter). Codec is more complex device, which has ADC and DAC.

The story in the datasheet warns that computer generated audio can have unhearable high frequency content which can interfere with the internal pulsed operation of the D-class amp IC. Some hearable mixing results can be generated and that's noise.

The datasheet guides to add extra RC filter to the input of the amp IC to reduce that noise. The filter attenuates the possible hf content of the audio.

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  • \$\begingroup\$ While in this case it is, in actuality a CODEC's output does not have to be analog. It may instead be some kind of pulse encoding - especially now that popular amplifiers are mostly implemented with switching rather than linear techniques, in a highly integrated system (like a phone) there may be no reason to go to analog in between, and simplicity reasons not to. \$\endgroup\$ – Chris Stratton Jan 13 '18 at 1:31

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