LMK04806: Phase noise issue in 20k frequency domain

Gary Zeng

Part Number: LMK04806

Tool/software:

Hi Ti experts,

There is a phase noise in frequency domain from 20kHz on CLKout3 port. There is only one chip that has issue. Normal altitude is -120dBc, wrong value is -110 or -115.

When customer reconfig all the registers of LMK04806 or shut down whloe machine and turn it on, the problem will occur or disappear, it is sporadic.

Could you please help register inromation and schematic.

5025.LMK04806 config which can not be locked in TI EVM.tcs

5025.LMK04806 clock sch.pdf

10 months ago

0 Kadeem Samuel 10 months ago

TI__Mastermind 22710 points

Hello,

The team is out of office for the holiday weekend. Please expect a response on Monday.

Thanks,

Kadeem

0 Gary Zeng 10 months ago in reply to Kadeem Samuel

TI__Intellectual 1225 points

Hi Kadeem,

Thanks for your reply. Look forward to your reply this night. Customer needs to confrim it tomorrow.

0 Michael Srinivasan 10 months ago in reply to Gary Zeng

TI__Genius 9420 points

Hi Gary,

Would you be able to provide a screenshot of the PNA measurement showing the issue? You mentioned that one chip has the issue. How many chips do you have that are not exhibiting the issue?

Thanks,

Michael

0 Gary Zeng 10 months ago in reply to Michael Srinivasan

TI__Intellectual 1225 points

Hi Michael,

Thanks for your reply.

Add PNA measurement curve.

As you can see, there is a floor above 20k. It is random. It may occur when after machine powers up or all registers resetting.

0 Michael Srinivasan 10 months ago in reply to Gary Zeng

TI__Genius 9420 points

Hi Gary,

Thank you for sending the PNA measurement. I will see if I can replicate this issue in lab tomorrow.

Thanks,

Michael

0 Gary Zeng 10 months ago in reply to Michael Srinivasan

TI__Intellectual 1225 points

Hi Srinivasan,

Look forward to your reply.

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LMK04806: Phase noise issue in 20k frequency domain