LMK04803: LMK04803B -TICS PRO-PLL2 is not locking

Nasim Soufizadeh

Part Number: LMK04803

Hello,

We are using LMK04803B on our board and the output measured frequencies are not at the expected values. TICS PRO has been used for the settings and the output has been programmed for 10MHz and 25MHz but we are getting 10.9 MHz and 27.24 MHz; around 9% increase in the frequencies. Please see the attached figures and I will be thankful if you could provide some feedback.

Sincerely,

Nasim.

over 3 years ago

0 Derek Payne over 3 years ago

TI__Mastermind 28960 points

Hi Nasim,

Your images didn't make it, can you please use the "add image" button in the editor to re-upload?

Additionally, can you please save the TICS Pro configuration and upload it to E2E for my review?

Regards,

0 Nasim Soufizadeh over 3 years ago in reply to Derek Payne

Prodigy 110 points

0 Nasim Soufizadeh over 3 years ago in reply to Derek Payne

Prodigy 110 points

6523.LMK04803B.tcs

0 Nasim Soufizadeh over 3 years ago in reply to Derek Payne

Prodigy 110 points

0 Derek Payne over 3 years ago in reply to Nasim Soufizadeh

TI__Mastermind 28960 points

Hi Nasim,

Thanks for uploading the TCS file. I see that you have PLL2_N_CAL=8 and PLL2_FAST_PDF=1. Please try setting PLL2_N_CAL=19 (to match your N-divider, since zero-delay mode is not being used) and PLL2_FAST_PDF=0 (since the PLL2 phase detector frequency is < 100MHz), and reload the register settings. Both of these controls can be located in the "User Controls" page. Refer to datasheet section 8.6.3.16.3 for more details on PLL2_N_CAL, and 8.6.3.16.2 for more details on PLL2_FAST_PDF.

I've attached the TCS file with the above modifications, for your convenience. Please try this and see if it resolves the issue.

6523.LMK04803B_TI_20201216.tcs

Regards,

0 Nasim Soufizadeh over 3 years ago in reply to Derek Payne

Prodigy 110 points

Thanks a lot Derek for the help, much appreciated.

Sincerely,

Nasim.

Clock & timing

Clock & timing forum

LMK04803: LMK04803B -TICS PRO-PLL2 is not locking