TAS5717: MCLK Frequency range

K.Shidara

Expert 3225 points

Part Number: TAS5717

Hi Team,

Regarding the upper limit of the MCLK Frequency specification of 24.576MHz in the

PLL INPUT PARAMETERS AND EXTERNAL FILTER COMPONENTS item of the data sheet,

is this value the upper limit including jitter and frequency deviation?

When MCLK = 512fs at Fs: 48kHz, it becomes 24.576MHz,
In this case, there is no margin, I would like to confirm.
If you have a margin, can you tell me the upper limit?

Thanks

Best regards,

Shidara

over 5 years ago

0 Alix Wan over 5 years ago

TI__Genius 9995 points

Hello Shidara,

You can configure MCLK=512Fs=24.576MHz without concern. The maximum/min value for MCLK listed in the datasheet is mainly for the limit of configuration.

For example, when MCLK=512Fs=24.576MHz, if variations occur in Fs, eg Fs=48.2MHz, then MCLK= 24.68MHz. This kind of variation is ok. But if MCLK = 513 or more * Fs, it is not allowed.

Regards,

Alix Wan.

0 K.Shidara over 5 years ago in reply to Alix Wan

TI__Expert 3225 points

Hi Alix,

Thanks for your advice.

MCLK provided from former circuit included jitter and max frequency will be 24.75MHz.

Is it OK for TAS5717?

Thanks

Best regards

Shidara

0 Matthew Miao over 5 years ago in reply to K.Shidara

TI__Expert 6720 points

Hi Shidara,

It should be OK.

Regards,

Matthew

0 K.Shidara over 5 years ago in reply to Matthew Miao

TI__Expert 3225 points

Hi Matthew-san

Thanks for your advice.

Because the maximum/min value for MCLK listed in the datasheet is mainly for the limit of configuration only,

is it possible to indicate the tolerance of variation including jitter?

ex) Within plus or minus 1%.

Thanks

Best regards,

Shidara

0 Luis Fernandes de Pina over 5 years ago in reply to K.Shidara

TI__Genius 15080 points

Hello Shidara,

Most Crystals have a frequency tolerance less than 30ppm and stability less than 50ppm. This should be fine for our device.

Best Regards,

Luis

0 K.Shidara over 5 years ago in reply to Luis Fernandes de Pina

TI__Expert 3225 points

Hi Luis,

Thanks for your comment.

Since the audio CLK is generated by decoding the audio data superimposed on the video signal,

it contains a large amount of jitter when compared to a crystal oscillator or the like.

If you could indicate the permissible variation, it will be helpful for the customer.

Thanks in advance.

Best regards,

Shidara

0 Caro Walter over 5 years ago in reply to K.Shidara

TI__Mastermind 22172 points

Hello Shidara,

When you say it contains a large amount of jitter, can you specify an amount?

All the best,

Carolina

0 K.Shidara over 5 years ago in reply to Caro Walter

TI__Expert 3225 points

Hi Carolina,

Thanks for your support.

Jitter will be +0.71%(max).

(24.75MHz / 24.576MHz)

How is it?

Thanks

Best regards,

Shidara

0 Caro Walter over 5 years ago in reply to K.Shidara

TI__Mastermind 22172 points

Hello Shidara-san,

If your MCLK variation is between 24.576MHz - 24.75MHz than that should be okay even though it is above the max parameter of the datasheet.

Would not recommend anything higher than 24.75MHz.

All the best,

Carolina

0 K.Shidara over 5 years ago in reply to Caro Walter

TI__Expert 3225 points

Hi Carolina-san

Thank you very much for checking.

I understood. Let me inform this to my customer.

Thanks

Best regards,

Shidara

Audio

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TAS5717: MCLK Frequency range