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TLV320ADC3120: background noise and pop noise

Kevin Huang8
Genius 3535 points
Part Number: TLV320ADC3120

Hi Team,

Please confirm the register table and circuit.

1) There is loud background noise.
2) There is "POP noise" when recording is turned on (I2S signal turn off and turn on), If I2S signal always turn on, there will be no pop noise phenomenon.

  • 0
    TI__Genius 16050 points

    Hi Kevin, 

    To help mitigate background noise coupling into the input you can implement RC filters as shown in your schematic, my only concern is that there is only a low pass filter on the positive path of your differential signal. Applying the filters to both may help here.

    In addition you can toggle the internal high pass filter in register 0x6b (h) to help mitigate noise in the front end.

    In regards to the POP noise, this can be expected when removing the clocks from the IC while recording, there is no time to ramp so soft-stepping and popping may occur. My suggestion to help this references my first point; popping could also occur due to the lack of impedance matching at the input pins. You can try toggling the internal impedance of input pins in register 0x3c and 0x41 OR modifying the input circuit.

    Regards,

  • 0 in reply to Daveon Douglas
    Genius 3535 points

    Hi Daveon,

    We found that after unplugging the microphone, the background noise will become smaller. Can you recommend the RC setting of the front-end line?

  • 0 in reply to Kevin Huang8
    TI__Genius 16050 points

    Hi Kevin,

    There isn't a standard filter we suggest to use as a front end to the ADC. This ultimately depends on the customer's cutoff frequency  and common mode voltage they desire, you can simulate the A/C response of this circuit on a tool such as PSPICE or Multisim to achieve your ideal signal.

    Regards,