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Original question:

TLV320ADC5120: ADC Sampling Performance

TLV320ADC5120: ADC Sampling Performance

Allan Wegner
Prodigy 30 points

Part Number: TLV320ADC5120

Tool/software:

What is the digital output RMS noise level in LSBs for a zero signal (0 V) input signal level for this device?

  • 0
    TI__Genius 9020 points

    Hi Allan,

    The datasheet specifies the SNR spec for the device for when the inputs are AC-coupled to GND (so input is 0V). This is specified for when 32-bit capture is done.

    Thanks and Regards,

    Lakshmi Narasimhan

  • 0 in reply to Lakshmi Narasimhan Badrinarayanan
    Prodigy 30 points

    No, this does not resolve our issue fundamental concern with this part.  We would like to specify the part, but we some assurance of its performance..  We are aware that the data sheet specified the overall SNR for the device for different configurations. as you indicated in your response.

    However, the data sheet does not specify the behavior of the LSBs at zero input.  What concerns us is your Application Note slaaed2a: “Increasing the Dynamic Range and SNR of Audio ADC with Channel Summation”.  The second sentence in that AN states: "This application note demonstrates how the dynamic performance of ADC increase by a factor of 3 dB for every doubling of the number of converters used in parallel.”.  To us this AN would imply there is something happening with several of the LSBs with zero input.

    As noted in my Chat session, our application is characterizing low amplitude sounds in the presence of higher amplitude interfering sounds.  So the performance of the LSBs due to self generated noise is a significant concern.

    We believe that you must have some data based on LSB performance after reviewing your published information on this device.  We appreciate any help you can provide.  Thank you.

    Regards..............Allan

  • 0 in reply to Allan Wegner
    TI__Genius 9020 points

    Hi Allan,

    My apologies, I'm still not very clear on the required information here: The SNR specified at idle channel is measured from the ADC's captured output digital code (with the A-weighting filter applied as mentioned in the datasheet) at zero input, so I'm trying to understand what the specific information is that you are looking for.

    Additionally, the section 2 describes how the channel summation feature improved the SNR by the 3dB factor, based on 6dB signal gain and 3dB noise gain.

    Is there any other additional information that we are looking for here?

    Thanks and Regards,

    Lakshmi Narasimhan

  • 0 in reply to Lakshmi Narasimhan Badrinarayanan
    Prodigy 30 points
    Yes, indeed there is more data that is needed regarding jitter and internal device noise in the LSBs. I need to think about how to better explain our issue for you, but I am currently traveling for the rest of the week. It may take a day or two for me to get back to you.
    Regards
  • 0 in reply to Allan Wegner
    TI__Genius 9020 points

    Hi Allan,

    Sure, I will wait for your follow-up to understand exactly what your requirements are.

    Thanks and Regards,

    Lakshmi Narasimhan

  • +1
    Prodigy 30 points

    Hi Lakshmi,  After doing further research, it turns out that you and I have been talking past each other as my colleagues and I are not familiar with audio recording industry standard terminology.  Now that we understand audio recording industry terminology, we now understand the capabilities of this TI-Burr Brown part. and are comparing it to other ADCs on the market.  Thank you for your help.