AIC32x4 ADC mute pop sound

Hi, Nick,

Welcome to E2E and thank you for your interest in our products.

Could you provide your TLV320AIC3204 schematic and your register configuration, please? It is to have a better approach to this issue.

Additionally, I suggest to take a look at this application report: www.ti.com/.../slaa404c.pdf. It explains the suggested design and the best register programming sequence to get the best performance.

Best regards,
Luis Fernando Rodríguez S.

Hello Luis,

thanks, I would check it with my design! But I thick the pop sound is from AIC32x4 itself.

I found the issue, and reproduce on AIC3254 EVM-U, and use the typical high performance record config in control software. You can observe the pop sound while press ADC mute\unmute button.

By the way, the DC offset from ADC is pretty high... it would impact dynamic range.

Thanks,

Nick.

Hello, Nick,

The DC offset that you refer probably is related with the common-mode input voltage. This common-mode input voltage is used to avoid any negative voltage at the analog input. In order to get a slower common-mode voltage, I suggest to see the analog power-up section of the AIC3254EVM-U GUI. The analog blocks can be powered slowly to avoid the pop issues.

Please let me know if the problem persists.

Best regards,
Luis Fernando Rodríguez S.

Hello Luis,

I've tried change common mode voltage 0.9V<->0.75V, the ADC DC offset problem is still there, and the DC level are the same.

My main problem is the pop sound at mute moment.

You can try it if you have AIC32x4 EVM kit.

Hello, Nick,

I'm still checking this. I will let you know my results as soon as I have them.

Best regards,
Luis Fernando Rodríguez S.

Hello, Nick,

I would suggest to take a look at Page 1 / Register 58: Floating Input Configuration Register. This register configures the IN pins as anti thump.

Additionally, could you verify if all the jumpers and switches of the EVM are in default position? (www.ti.com/.../slau266a.pdf

Best regards,
Luis Fernando Rodríguez S.

Hello, Luis,
I am using EVM-U which size is like USB flash disk, and there is not any jumper.
But i would try anti-thump function, thanks!

hope it can work well.
Nick.

Update:

The anti-thump is trying to avoid the input pin voltage from undefined to common-mode, it is not helpful to solve pop sound...
Now I am trying is to +12dB on ADC gain, and -12dB on adaptive filter N0 coef, the overall gain path is unchanged. before mute, degrade ADC gain 0.5dB step by step til -12dB. So that I can heve 24dB softmute(by hand...lol) range to smooth the pop sound. But the only risk is clipping signal, because of +12dB in front of -12dB...

Nick.

Hi, Nick,

Excuse me, did you get any advance on your last test?

Best regards,
Luis Fernando Rodríguez S.

Hello Luis,

Yes, softmute can improve this issue greatly.
But softmute is workaround solution... I think the root cause is hardware issue, could you please help ask RD this issue??

Thanks,
Nick.

Hello, Nick,

Could you provide a schematic, please? It is to ensure if it could be related with a hardware issue.

Thank you.

Best regards,
Luis Fernando Rodríguez S.

Hello Luis,

slau295a_new.pdf

I attached EVM-U schematic, the issue can 100% reproduce in the EVM-U.
As for my schematic, it is company confidential, do you mind give me your email address? 

Thanks so much!

Nick.

Hi, Nick,

You may send me the schematic via message. You should be receiving an e-mail from me.

Best regards,
Luis Fernando Rodríguez S.

Hi, Nick,

I already reviewed your schematic.

First of all, we need to ensure that the power supply sequencing is being applied correctly. The most part of the pop issues are related with how the power supplies are being provided to the codec. Please, take a look at this document for details:

http://www.ti.com/lit/an/slaa492a/slaa492a.pdf

Then, I noticed that some of your analog inputs are not being used. We always suggest to connect the unused capacitors to GND. This is made to avoid that any undesired signal will be routed to the codec.

Finally, since the analog power blocks are strongly related with these issues, I also recommend to modify the analog blocks power time. Page 1 / Register 123 is used to power up the analog blocks slowly.

Please let me know if you have more questions or comments.

Best regards,
Luis Fernando Rodríguez S.