TAS5727: Application of tas5727

Carl Shen

Part Number: TAS5727
Other Parts Discussed in Thread: TAS5805M

When I use tas5727 to communicate with the master I2S, when the master IC uses 11.2896m spread spectrum crystal oscillator, there will be a high frequency noise at 1.8khz. Please help to see if there is a solution, or can tas5727 use three wire system (no MCLK) to communicate with the master? The crystal oscillator uses sit9005 of SiTime

over 4 years ago

0 Leon Peng over 4 years ago

TI__Intellectual 2430 points

Hi Carl,

I don't have its EVM on hand so I need to check it with teams first then give some feedback to you.

BRs

Leon

0 Leon Peng over 4 years ago in reply to Leon Peng

TI__Intellectual 2430 points

Hi Carl,

You can refer to this E2E question:

https://e2e.ti.com/support/audio/f/audio-forum/253844/tas5727-without-mclk

Without an external MCLK, the device will not play audio. The internal clock (DCLK) is used to sustain operations like I2C communication & idle output PWM switching. So in effect what the datasheet statement is saying is "Even in the absence of MCLK, I2C read/write operations can be performed, and the output PWM will continue to switch in idle mode".

That being said, one option to use a single clock on both MCLK & SCLK is if a 44.1KHz/48KHz sample rate (i.e. LRCLK is used). With a 44.1K/48KFs rate, a 64*Fs clock can be used on both SCLK and MCLK pins.

BRs

Leon

0 he guixian over 4 years ago in reply to Leon Peng

Prodigy 70 points

Hi Leon,

I know the device will not play audio without an external MCLK.But I want to know Is there a way to prenvent the 1.8Khz HF noise when i use an spread crystal of SIT9005 on my MCU?

0 Leon Peng over 4 years ago in reply to he guixian

TI__Intellectual 2430 points

Hi He,

Our devices must need the stable I2S clock to output right audio. Are you sure that your I2S clock is stable?

BRs

Leon

0 Gregg Scott over 4 years ago in reply to Leon Peng

TI__Mastermind 40705 points

Closing this thread due to lack of response.

0 he guixian over 4 years ago in reply to Leon Peng

Prodigy 70 points

Hi，Leon，Do you mean that if we use TAS5727, we can't use Spread Spectrum crystal oscillator？

0 Leon Peng over 4 years ago in reply to he guixian

TI__Intellectual 2430 points

Hi He,

Yes, a spread spectrum ocs is not suggested to use.

But another way is that the TAS5727 can use the same clock for BCLK and MCLK (64×Fs) when operating at 48KHz/44.1KHz sample rates, which means you need to connect BCLK and MCLK together externally. If a different sample rate is used, a MCLK must be provided.

BRs,

Leon

0 he guixian over 4 years ago in reply to Leon Peng

Prodigy 70 points

Hi Leon,

OK,Thanks a lot.I try it. I don't know if it can't output the right audio.

0 he guixian over 4 years ago in reply to he guixian

Prodigy 70 points

Hi,Leon.I just test it.There will be a high frequency noise at 1.8khz. But our another product use TAS5805M, there won't be a high frequency noise at 1.8khz.

0 Leon Peng over 4 years ago in reply to he guixian

TI__Intellectual 2430 points

Hi He,

1. These two devices are different structure, TAS5805M is closed-loop and TAS5727 is open-loop. So TAS5805M has more ability to tolerate the interference

2. So all your I2S clock is generated by this spread spectrum crystal oscillator? If so, we suggest you should change one crystal oscillator.

RRs,

Leon

0 he guixian over 4 years ago in reply to Leon Peng

Prodigy 70 points

Hi Leon,

Thank you.

Yes,all our I2S clock is generated by this spread spectrum crystal oscillator.Because we need to obtain a better EMC test results, we must use ssco.General crystal oscillators or other crystal oscillators don't meet our demand.We have already decided to change our poweramplifier to TAS5805M.

0 Robert Clifton56 over 4 years ago in reply to he guixian

TI__Mastermind 25400 points

Hi He,

Let us know if you have any questions on the TAS5805M.

Closing this thread since you are changing devices.

Best regards,

Robert Clifton

0 he guixian over 4 years ago in reply to Robert Clifton56

Prodigy 70 points

Hi,Robert

I don't know how to close the thread since I have never used it before.

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TAS5727: Application of tas5727