TPA6120A2: Headphone power amplifier

I am looking at such a scheme. This is right?

How to change it for unipolar power supply?

What to do with unused pins?

Hello Gennadiy,

  Is the maximum voltage 2.7Vpp input to the TPA6120A2 biased to above ground? 

Thank you,

Sima

I did not quite understand.

Here is a diagram of the mixer where you will need to connect the headphones.

Hello Gennadiy,

  You may use the device as a single-ended input as you have shown in above image. However, you might want your outputs to be 180º out of phase which the above will not provide. Here is a quick overview of the concept.

  Also, for single supply version, it is important for the signal to be biased (usually at mid-supply) in order to avoid input and output voltage violations of the amplifier. In the mixer diagram, it shows device biased at Vref, but it looks like at the output there are AC coupling capacitors. Here is a link that covers the details for single-supply application. Within the introduction, the application note link by Texas instruments is outdated, here is the new link for the document discussed. Specifically for the TPA6120A2, the e2e thread covers the various load performance. Since this device is a current feedback amplifier, it is important to follow the feedback resistor recommendations in the datasheet (Figure 17). The resistor values in the first diagram you provided will work.

Thank you,

Sima 

Hello!

This is right? Will it work well?

What to do with pins 18 and 20?

Hello Gennadiy,

  Are you able to lower your component values? Increasing the feedback resistance can decrease stability and increase the distortion. The current-feedback amplifier recommends between 680Ohm to 1.5kOhms. 

  For biasing, I would probably add small decoupling caps at RIN+ and LIN+. Also, are you looking for the single-ended signals to be 180 degree out of phase from each other as explained earlier and shown in Figure 2 this link? 

  For pins 18 and 20, these are the power supplies of the right channel of the device. Pin 18 would be connected to VCC and pin 20 is to GND.

Thank you,

Sima 

Thank you!

Now right?

SimaJalaleddine said:

For biasing, I would probably add small decoupling caps at RIN+ and LIN+.

I installed a C20 capacitor for this. Isn't it enough?

SimaJalaleddine said:

ou looking for the single-ended signals to be 180 degree out of phase from each other as explained earlier and shown in Figure 2 this link

I'm not good at circuitry. I don't understand you very well. I need a normal working stereo headphone amplifier. These additional headphones are required by the sound engineer. As far as I understood, figure 2 is a bridge inclusion. This is not required. What do I need to change in the circuit for it to work properly? Perhaps you could draw the missing elements? This week there will be an order for other printed circuit boards. And, if I don't have time to add this amplifier to the total order, I will have to pay an additional 30 dollars for shipping. I apologize for bad english. Thanks again!

Thank you!

Sending an order for a prototype PCB today.

Good luck and have a nice day!