TLV320AIC3105 - Analog Out Level vs Analog Input

Hi, Bruno,

This should be related with the register configuration. Could you provide your register values, please?

Best regards,
Luis Fernando Rodríguez S.

Hi. Thank for quickly answer.

- I use single ended output (reg 37)
- To connect IN2R to HPRCOM I use reg 69(vol) & 72(out)
- To connect IN2L to HPLCOM I use reg 52(vol) & 58(out)
- To connect IN2R to RIGHT_LOP/M I use reg 90(vol) & 93(out)
- To connect IN2L to LEFT_LOP/M I use reg 80(vol) & 86(out)

Volume registers are = 0x80 (0dB)
Output Level Registers are = 0x0F (0dB)

Output levels are half of input Levels .... WHY?

Regards Bruno

Hi, Bruno,

In cases where the active analog bypass is used, it is necessary to configure the LINE2R/L inputs for this function. So, could you try configuring the Page 0 / Register 40 to use the lines in bypass mode?

Best regards,
Luis Fernando Rodríguez S.

Hello Luis.
Thank for your answer.
I can't use bybass function because I have need to adjust these signals out.
My wish I to reach (at least) the 0dB gain.

- In my application, I set all outputs as single endeed.
- I set Out common mode voltage = 1.8V
- When I set all registers for 0dB, I have signal out = 1/2 of signal input
- If I use Output Level Control Registers (72, 58, 93, 86), increase over the 3dB cause a clip on signal out.

Regards
Bruno

Hi, Bruno,

The TLV320AIC3105 has two kinds of bypass function:

- The passive bypass function doesn't allow to modify the gain. This means that the analog input will be routed directly to the analog output. This function can be configured with Page 0 / Register 108.

- The active bypass function can be used to route the analog input to the output mixers. This means that the IN2 could be routed to LEFT_LOP, RIGHT_LOP, HP outputs... This configuration is made by Page 0 / Register 40. If my understanding is correct, this would be your application (IN2 to analog outputs). Could you try using the active bypass mode?

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

Best regards,
Luis Fernando Rodríguez S.

Hi.
Thank you for your explanation.
I set the bits in reg.40 and now output is exactly how I exepcted.

Thank You very much for your support.
Now I continue the testing on my prototype.
If I will have other questions I call you.

Best Regards
Bruno Merlo

Hello Luis.
I have already another question:

I use IN3L for MIC detect.
In this input I have '0' when mic is not present and '1' (MICBIAS) when mic is present.
I try to read: reg14.4 - reg96.2 - reg97.2 but these bits remains always at '0'

How I have to proceed to use this function?

Greetings from Italy
Bruno Merlo

Hi, Bruno,

I'm glad to read that the last problem was solved.

Regarding the mic detect function, I would suggest to take a look at 10.3.10 Jack and Headset Detection section of datasheet. This section explains the necessary connections and registers to configure this functionality.

Please let me know if you have questions or comments about this section.

Best regards,
Luis Fernando Rodríguez S.

Hi, Bruno,

Additionally, I suggest to take a look at this application report:

www.ti.com/.../slaa454.pdf

Best regards,
Luis Fernando Rodríguez S.