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About the low frequency wave noise of TLV320ADC3101.

Satoshi
Guru 19575 points
Other Parts Discussed in Thread: TLV320ADC3101

The customer is evaluating TLV320ADC3101.
Then, the noise level of the low frequency wave region is troubled greatly.

I would like to improve climax of the noise which gets worse rapidly below 50Hz especially, and the noise near 100Hz.
A circuit diagram, a setting register, and a noise waveform are attached.
If there are a remedy etc., please let me know.

7217.TLV320ADC3101EVM_measurement.xlsx

2352.TLV320ADC3101_Register.xlsx

This characteristic is the same result also in an EVM board or a customer design board.
In addition, on the digital microphone of I2S output of the elegance of the other company, a rapid noise level change of a low frequency wave region is not visible.

[Supplement]
・I under check whether there is any noise in a power supply line and line-input.
・The clock is adopting how to use the following.

 

Thank you for your consideration.

  • 0
    TI__Guru**** 189399 points

    Hi, Satoshi,

    Sorry for the delay. I have asked my colleague to look into this with you.

    -d2

  • 0 in reply to Don Dapkus
    Guru 19575 points

    Dear Don-san

    I understand.
    Thank you for connecting.
    Please advise me, if an answer finds some.

    Best regards,

    Satoshi

  • 0
    TI__Mastermind 28585 points

    Hi Satoshi-san,

    I checked the ADC3101 EVM in the lab with the same conditions. Instead of a microphone, I used the line output from the Audio Precision. The first plot is with a -20 dB 900 Hz signal. The second plot is with no input. You can see the low frequency noise is quite good. I am not sure what the problem is with your customers setup. Perhaps there is some bad grounding??

    Best Regards,

    dave

  • 0 in reply to Converter Apps
    Guru 19575 points

    Dear Converter apps

    Thank you for advice and the data.

    About line-in, even if it carried out GND grounding of all the input terminals, the low frequency wave noise has not improved.
     
    About the power supply, the power supply of TLV320ADC3101 is supplied by the stabilized power supply for exclusive use.

    Moreover, change was not seen although an improvement, such as adding OS-CON to each power supply terminal, was tried.

    Anew, the specification of GND is checked with a customer.

    Moreover, there is additional information.
    A customer is going to use it by health care, and measures cardiac beats rate etc. using ADC3101 input from a wristband.

    For the reason, the noise of a low frequency wave becomes important.

    If there is a product which matched such usage, please let me know.

    Best Regards,

    Satoshi

  • 0 in reply to Satoshi
    TI__Mastermind 28585 points

    Hi Satoshi-san,

    If the customer can not reproduce my results on the EVM, then I suggest that there might be a problem with the customer's test setup. Do you have access to any local TI FAE to look at the customer's test setup?

    Best Regards,

    dave