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PCM5121: Recommended parts to improve SNR & THD+N for ADC AK5720 and DAC PCM5121

Ruben Juan Juan
Prodigy 55 points
Part Number: PCM5121

Tool/software:

Hello there,

I have a working prototype consisting of a wireless kit that sends analog audio over a wireless link to a receiver that outputs the signal also in analog format:

1-Analog input to AK5720 ADC to a Wireless TX Link

2-Wireless RX Link to PCM5121 DAC to analog output.

When I measure JUST the Wireless Audio TX to RX link using I2S IN and I2S out, the SNR is 140dB and THD+N is -95dB.

The prototype uses the AK5720 in the TX device and the PCM5121 in the RX device, the measured SNR is  92dB and THD+N is -70dB:

Question:

1-what ADC and DAC alternatives can I use to improve the overall SNR and THD+N audio performance and get closer to the I2S-only measurements?

2-Any recommended pre-ADC and post-DAC circuits to improve the SNR and THD+N? Any Application note

I appreciate any help you can provide.

Thanks

  • 0
    TI__Mastermind 26205 points

    Hi Reuben,

    First, can you provide the SNR and THDN measurements of the following signal chains:

    Analog Input -> AK5720 -> TX -> RX -> I2S Measurement

    I2S IN -> TX -> RX -> PCM5121 -> Analog Out

    This will help narrow down if either or both devices are degrading the THD+N and SNR. At least for the PCM5121 TI device, the SNR and THD+N are spec'd much higher than your final measurment.