LMK03328: Jitter performance differences between CLKOUTx clocks and STATUSx clocks.

user4779049

Part Number: LMK03328

Hi Team,

Please advise me on the jitter performance differences between CLKOUTx clocks and STATUSx clocks.

I want to use 30 MHz 3.3V LVCMOS clocks from LMK03328, (REF = 30 MHz)

The CLKOUTx does not support 3.3V LVCMOS output. So, level sifter ICs may be used with
LMK03328, when CLKOUTxs are used,

In the meantime, LMK03328 can output 30 MHz 3.3V LVCMOS clocks through STATUSx pins.
I want to know jitter performance difference between these two cases.

Please also let me know if there are any restrictions on functionality when STATUSx output is used compared to
The case CLKOUTx is used.

I appreciate your prompt feedback, because I want to fix design before the end of this week.

Mita

over 6 years ago

0 Brian Wang over 6 years ago

TI__Expert 7845 points

Hi Mita,

The STATUSx output path will not be as optimized as the CLKOUTx, the noise floor will be higher and thus higher jitter, more noticeable as well for lower frequencies like 30MHz. Do you have options to use other 3.3V output types or have less demand in jitter for the 30MHz signal?

Regards,

Brian Wang

0 Lane Boyd over 6 years ago

TI__Genius 16845 points

Hi Mita,

I tested in my lab and observed typical rms jitter of 235fs on STAT0, compared to jitter of 175fs on OUT0_N. I hope this information helps.

There won't be restrictions on functionality, but you will be unable to use status signals such as PLL Loss of Lock or Loss of Reference.

Kind regards,
Lane

0 user4779049 over 6 years ago in reply to Lane Boyd

Expert 2155 points

Lane-san,

Thank you for the answers.

Mita

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LMK03328: Jitter performance differences between CLKOUTx clocks and STATUSx clocks.