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TLV320AIC3109-Q1: Audio output Noise issue.

Jomin James
Prodigy 170 points
Part Number: TLV320AIC3109-Q1

Hi 

In our design, we are using TLV320AIC3109-Q1 for our mono channel audio output application.

We have configured the codec through I2C and Audio data is sending through the I2S interface. But the output audio is coming with a lot of background noise.

  • We are using a Mono channel speaker for the audio output speaker, which is responding perfectly to the phone audio out.
  • We have got almost better waveforms in I2S and MCLK lines as attached.(without any series termination). (We tried 33Ohm Series termination as well.)

  • Our Audio output implementation as follows.

Kindly help us to reduce the Noise issue we are facing on the Output Audio. Your support is highly appreciated.

Here attached an audio output record for your reference(One two three four ...).

  • 0
    TI__Mastermind 22950 points

    Hello Jomin,

    Is the noise on the line outputs? If so, is there a low pass filter? These devices have Out of Band Noise on the line outputs that can get aliased back in to the audio band if using an amplifier with no low pass filter between the codec and the amp. 

    If there is no LPF, I recommend adding a simple RC LPF with a cutoff of ~30kHz. 

    Regards,
    Aaron

  • 0 in reply to Aaron Estrada
    Prodigy 170 points

    Hi Aaron

    We are using line outputs. There was no LPF filter on the line initially though there was an option to add it.

    We tried putting RC LPF in the audio line(30Khz cutoff). But the noise still persists and audio coming with similar Noise

    Are there any other register configurations we need to put more attention on? 

    Please verify current register settings below,

    w 30 07 80
    w 30 07 8A
    w 30 09 04
    w 30 25 C0
    w 30 29 02
    w 30 2B 00
    w 30 52 80
    w 30 5C 80
    w 30 4B 80
    w 30 4E 80
    w 30 56 09
    w 30 5D 09
    w 30 4F 09

    Schematics for your reference.

  • 0 in reply to Jomin James
    TI__Mastermind 22950 points

    Hello Jomin,

    Can you reupload an image of the schematic? For some reason, it is not showing up. Since you are inquiring about the AIC3109-Q1 EVM in another post, are you using the EVM here or is this a custom board?

    Looking at the register settings, it looks like you should be in DSP mode but the CODEC is set to use I2S. Please write 0x44 to register 9. (w 30 09 44).

    Regards,

    Aaron

  • 0 in reply to Aaron Estrada
    Prodigy 170 points

    I hope the attached schematics is OKe.
    It is a custom Board and we are using the AIC3109-Q1 codec on the board. We were using EVM for our initial development activities.

  • 0 in reply to Jomin James
    Prodigy 170 points

    Hi Aaron 

    We have tried the below suggestion but still, the Noise issue is persisted.
    Looking at the register settings, it looks like you should be in DSP mode but the CODEC is set to use I2S. Please write 0x44 to register 9. (w 30 09 44)

    Kindly Guide us to solve the noise problem we are facing. Still, we are unable to identify the source of Noise. Our power sequencing and RESET timing are correct as per requirement.

     

  • 0 in reply to Jomin James
    TI__Mastermind 22950 points

    Hello Jomin,

    It also looks like the WCLK and BCLK are misaligned. Please refer to the image below taken from the data sheet that shows the WCLK edges should be aligned with the rising edges of the BCLK. 

    I would also like to ask about your clock signals. Form the above images, is MCLK to be 12.288MHz? And I assume you are not using the PLL as it is disabled. Is this correct? If you are not using the PLL, please also write 0x01 to register 101. This will select CLKDIV_OUT for the Fs. By default it is selecting the PLLDIV_OUT path. 

    Regards,

    Aaron