TPA3126D2: Output drops by 6dB

No, I replaced the amp chip with the TPA3156 at the same 26dB gain and it still had the problem.  And no the output was a perfect sine wave, no clipping.

The load during this testing is a 4 ohm resistive load, and I'm running it at about 25Wrms.  Yes I do know the differences in the power output, but since the new chip had the same issue it really doesn't matter.

So no comments on my reduction of the gain to 20dB, then increasing the signal into the amp by 6dB to make up for the difference, and the issue no longer is there?  Modified two boards now with the same results.  So again, WHY don't you answer my questions about the gain settings. 

So I expanded the time domain so you can see the waveform at the load.  There is no clipping, nor is there any clipping in any of those previous waveforms.

Hi,

I do suggest you find a local TI support. An onsite support may will helps resolve this issue more efficiently. From the E2E information, we can not find the root cause, and as you know it is hard to HW debug without board in hand.

As talked before, the Gain setting is latched and locked when power up. If SDZ pin is toggled, Gain setting will be latched again by sample Gain pin voltage.

We don't seem to be communicating, and you keep replying with non-answers.  Yes I already know, and have previously stated in this thread the information you just stated regarding the gain setting.  That is NOT what I asked.   What I DID ask was when I set the part for 26dB gain, is that for single ended input, differential input, or it doesn't matter because the part compensates for the input configuration?  

WHICH is it?

As for "local TI support", TI makes it impossible to know who to contact.  You provide me with contact information, and I will happily contact them.  So ask yourself, if you (who work for TI and have FAR more contacts there than I do) can't find out who I should contact, then how do I?

This whole thread has become an exercise in futility.

Hi,

Audio input configuration does not affect Gain setting. 

Could you provide your company information? Maybe I can search who can support you on-site.

I work remotely for Mitek, so I need someone who covers the Portland Oregon area.  I report into our Phoenix, AZ site.  So exactly what company information are you looking for?  Web site is MiTek Corporation (mitekusa.com)