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PCM4201: PCM4201 design issue

Lonnie Kim
Prodigy 20 points
Part Number: PCM4201

Dear TI

I'm debugging PCM4201 because audio noise.

1. System block

2. Mode setting(Master or Slave)

- We are using 11.025KHz sampling frequency.

- Which mode(Master or slave) can be set?

 > Slave: 256fs or 512fs

 > Master: 512fs

2. About Frame

- Currently, 1 frame was 126BCK not 128BCK. How can I modify?

- We set Normal Speed, high performance mode. Is it same as below "BCK = 128fS when Normal Speed, Low Power sampling"?

       > If BCK = 128fS when Normal Speed, Low Power sampling is enabled, then the frame will begin on the falling edge of the FSYNC clock input.

The FSYNC clock is inverted for this case.

- Can you explain High performance mode and Low power mode in Normal speed?

3. Frame sync

- Data is observed previous FSYNC. Is it OK? I think applied BCK delay.

  How about your opinion?

4. Not matched One frame size.

-  One Frame = 1/Fs = 128BCK(Normal mode)

  > 1 Frame = 1/Fs = 1/11.025KHz = 90.7029us

           > 128BCK = 128 * 0.354 = 45.312us(waveform 45.30us) --> Not matched

- Is it OK?


5. System Clock

Current system clock: 11.11MHz

Master mode – Normal speed: 512fs = 512 * 11.025KHz  = 5.6448MHz -> Not matched

Is it OK?


 

Please help me.

We cannot next design step because this issue.

 

Best regards

 

Lonnie Kim

  • 0
    TI__Mastermind 30100 points

    Lonnie, 

    1. ok

    2. yes, that is correct. 

    2a. the Datasheet explains normal speed low power vs normal speed high performance. see below

    The PCM4201 includes three sampling modes, supporting sampling rates up to 108kHz. The Normal Speed, Low Power mode supports sampling rates up to 54kHz, and employs 64x oversampling to reduce overall converter power. The Normal Speed, High Performance mode supports sampling rates up to 54kHz with 128x oversampling, resulting in improved dynamic range and THD+N when compared to the Low Power mode

    3. Can you try changing the PCM master so that the bclk rising edge is sycned with the Fsync rising edge? 

    4. I wouldn't recommend using cursers to measure frequency. Use the scopes built in measuring functions to measure frequency.

    5. Your MCLK should not be a sidnewave, it should be a square wave.  and the MCL should be either 256 x 11.25khz or 512x 11.25khz  you don't have options there. 

    best regards,

    -Steve Wilson