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PCM1821: PCM1821 How to I2S 0dBFS output?

rd1
Prodigy 20 points
Part Number: PCM1821

Hi TI Teams

We are using the PCM1821 to do ADC design, when inputting 2Vrsm signal or inputting 3Vrms signal, the I2S signal output from the ADC can't go to 0dBFS, how can we make the PCM1821 I2S output go to 0dBFS?

The hardware design is as follows：

AVDD and IOVDD=3.3V

MD0=0

MD1=1

MSZ=0

FMT0=0

thanks！

  • 0
    TI__Genius 16130 points

    Hi RD1,

    PCM1821 supports a 2Vrms signal for a differential input signal configuration while your current setup is configured for single-ended. I suggest trying to input a 1Vrms signal with your current setup or providing a differential signal.

    3Vrms is also not supported, this will result in audio clipping.

    Regards,

  • 0
    Prodigy 20 points

    Hi 

    Thank you for your reply

    Can the I2S output reach 0dBFS by inputting a 1-volt differential signal?

    Or how much amplitude signal is input can the I2S output go to 0dBFS?

    Regards,

  • 0 in reply to rd1
    TI__Genius 16130 points

    Hi,

    The datasheet does not specify this device supports a single-ended configuration. You can try a 1Vrms signal to test if the output is satisfactory.

    Otherwise, customer must change input to a differential configuration and apply a 2vrms signal to achieve 0dBFS.

    Regards,