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TLV320ADC5140: About Specification

minook kim
Prodigy 40 points

Part Number: TLV320ADC5140

Dear TI,

I am considering this device to adopt for recording system.

The Main purpose is SNR boost for very small signal recording.

So, I have couple questions.

Q1)  What is the PGA input-referred noise level at AVDD 1.8V/3.3V and PGA 0dB/24dB ? (A-weighted, input grounded, BW 20hz~20khz)

Q2)  Which Input impedance selection is the best in case of differential AC-coupled (1uF) input ?

        Does it select HPF cut-off frequency ?

Q3)  About DRE enable mode

      1. is it available summing mode at the same time ?

      2. is it available additional gain after DRE block ? if possible, what is the maximum additional gain ?

Q4) Recommend me the setting (channel summing mode, DRE..etc) to make the best SNR boost, in other words, to make the noise level degradation.

Best Regards,

minook

  • 0
    TI__Mastermind 23050 points

    Hi Minook,

    Glad to hear you are interested in our latest audio devices! To answer your questions:

    1) The PGA input noise is ~2uVrms. You can approximate the total input referred noise using the SNR/dynamic range spec, here is a similar post walking through this: https://e2e.ti.com/support/audio/f/6/p/872687/3229372#3229372

    2) This depends on your source. Lower input impedance settings will provide the best noise performance, but if your source is high impedance and you don't have the ability to buffer it you may want to use a higher input impedance setting. This will shift the HPF cutoff frequency formed with the AC coupling capacitor and you may need to adjust the value of this capacitor accordingly. Note, the device also incorporates an internal HPF to eliminate any offsets that accumulate through internal circuitry.

    3) It is not recommended to use DRE and summing of the channels as the DRE takes place in the same DSP for each channel and there are internal delays that may result in slightly different gain values that could negatively impact the result.

    You do have the option to use the digital gain adjustment after the DRE which can be adjusted from -100dB to 27dB.

    Hope this helps!

    Best,

    Zak