PCM1754: Pop noise question

Ryo Akashi

Part Number: PCM1754

Hello experts,

My customer is using PCM1754 and have pop noise trouble.
With refereeing some thread about PCM1754 pop noise, customer tried setting MUTE low before stopping CLK to prevent pop noise, but result is not well.
Attached file is waveform about DAC output and CLK and MUTE. There is pop noise even if MUTE become low before stopping CLK.
Could you give us advice how to prevent pop noise?
PCM1754_pop_noise_question.xlsx

Thanks and best regards,
Ryo Akashi

over 2 years ago

0 Arash Loloee over 2 years ago

TI__Mastermind 21660 points

Hello Ryo,

we will take a look at it and let you know.

Regards,

Arash

0 Arash Loloee over 2 years ago in reply to Arash Loloee

TI__Mastermind 21660 points

Hello Ryo,

After reading your post again, I am wondering if you are asking about a pop noise or you are asking about the output level after halting the clock.

If you are asking about the DC level of the output, I think it is the similar issue to the one mentioned in this post:

https://e2e.ti.com/support/audio-group/audio/f/audio-forum/956405/pcm1754-q1-pop-noise-issue

" .....the delta-sigma modulator will stop operating at the last static DC voltage, which you are showing in the image."

Kind regards,

Arash

0 Ryo Akashi over 2 years ago in reply to Arash Loloee

TI__Genius 9340 points

Hello Arash-san,

Thank you for your reply.
I'm asking about pop noise and it's helpful if you would provide advice for pop noise.
Do you have any idea of solution for this pop noise?

Thanks and best regards,
Ryo Akashi

0 Arash Loloee over 2 years ago in reply to Ryo Akashi

TI__Mastermind 21660 points

Hello, in the excel sheet you sent form customer, it isays:

"DAC output voltage will be strange value when there is not SCK input. It is not related with MUTE status."

which I think the post above applies to this observation. There is no pop noise in the waveform that I can see or no mention of it by the customer .

would you please send me an email if you have any question about this?

Thanks.

Regards,

Arash

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PCM1754: Pop noise question