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I'm planning to use TPA2012D2 (http://www.ti.com/lit/ds/symlink/tpa2012d2.pdf) audio amplifier from TI from my headphone audio project. This amplifier has a differential outputs for left and right audio channels.

My question is, how do I connect this to an headphone jack where I have a common ground for both channels? Is it possible to use just the OUTL- and OUTR-, and ground the OUTL+ and OUTR+?

(This is the typical application schematic found in the datasheet) enter image description here

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  • \$\begingroup\$ You can generally ignore the OUT- outputs, simply use OUT+ and GND. \$\endgroup\$ – Brian Drummond Aug 9 '16 at 9:00
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Each channel output is a H bridge therefore you cannot cross connect speaker wires to form a common 0V. You could use a transformer to convert a balanced output (H bridge output) to a single ended output and you'd need one transformer per output.

You might be able to use the half-H bridge outputs but distortion and other problems may occur due to imbalanced loading. Read the data sheet to see what it says.

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  • \$\begingroup\$ Ok, now I understand. This is the answer I was looking for, the theory behind it. Thanks so much! I'll switch to another device as @pjc50 proposed. \$\endgroup\$ – StjepanV Aug 9 '16 at 9:12
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    \$\begingroup\$ There are plenty of options: LM4880, LM4910, MAX97200, TDA1308, MAX4298, LM4809/10 etc.. google.co.uk/… \$\endgroup\$ – Andy aka Aug 9 '16 at 11:01
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Look at the other example schematic which shows a headphone socket:

Schematic

It's driven from a TPA4411 instead. I think the TPA2012 is a bit high-powered for headphones anyway.

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  • \$\begingroup\$ Thanks for the answer! I need to switch to another device as you say, and from the answer that Andy aka gave. Thanks guys! \$\endgroup\$ – StjepanV Aug 9 '16 at 9:13
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    \$\begingroup\$ .. TI have of course reccomended a more expensive part, whereas a quick check of digikey suggests ti.com/lit/ds/symlink/lm4808.pdf LM4808 - note the much lower output power into a higher impedance. Headphones are 16-32ohm rather than 4-8ohm. \$\endgroup\$ – pjc50 Aug 9 '16 at 9:28
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    \$\begingroup\$ This is the right answer. The amp is used for the loudspeakers in the handeld device, not for the headphones. \$\endgroup\$ – Vladimir Cravero Aug 9 '16 at 9:57

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