PCM5102A: D/A Analog output level not what I expected?

Randy Woods

Part Number: PCM5102A

I cannot achieve a 2.1VRMS full scale Analog Output signal from a 1KHz full source.digital media (USB (.mp3)/DVD Created my own media/CD (Converted the .MP3 to CD) I can output 2.0V RMS but is clipping, the best unclipped output is 1.77V RMS. Is that the best I should expect? Or is something wrong. I have a solid 1.8V and 3.3V DVDD. Any advise?

Thanks

over 6 years ago

0 Paul_Frost over 6 years ago

TI__Guru 53343 points

Hi Randy,

Do you think you could share your schematic? Do you have any output buffer?

Thanks!
Paul

0 Paul_Frost over 6 years ago in reply to Paul_Frost

TI__Guru 53343 points

Any updates?

0 Randy Woods over 6 years ago in reply to Paul_Frost

Prodigy 40 points

I have a MT3373 connected directly supplying the I2S input. I have adjusted the output series resistor and capacitors from the recommended 470 ohms to 0 ohms. I have a tried multiple media sources with with Full-scale 1KHz Audio (DVD , a CD, and a USB with a .MP3 file) and yielded the same results. I can get 2.0V RMS but is a clipping signal? I believe the issue is in the output from the MT3373.

Thanks

0 Paul_Frost over 6 years ago in reply to Randy Woods

TI__Guru 53343 points

Hi Randy,

I recommend that you verify that the PCM data in is the I2S format, at a supported sample rate as shown on table 10 of the PCM5102A PDS. While I do not think it will cause your issue, I do recommend you populate R268, R269, C269, and C279 to implement a LPF and reduce out of band noise.

Thanks!
Paul

0 Randy Woods over 6 years ago in reply to Paul_Frost

Prodigy 40 points

Thanks, i have the sample rate and clock set to the following:

Sample rate LRCLK :48KHz

Clock is BCLK: 3.07MHz

Main clock: MCLK: 12.288MHz

0 Paul_Frost over 6 years ago in reply to Randy Woods

TI__Guru 53343 points

To confirm, you see an output of ~2.1VRMS but it is clipping? If that is the case, then I think you have applied some digital gain in your MT3373 that needs to be reduced. The PCM5102A does not have a gain setting. Please share an oscilloscope capture of the output as well.

Thanks!

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PCM5102A: D/A Analog output level not what I expected?