LMK05028: Please review customer's schematic, setting

Hironori Yoshimura

Part Number: LMK05028

According to my customer, Customer would like to adjust thru I2C control.

Customer's pre-set freq is 148.5MHz. Then He would like to control decreasing lock-FREQ by I2C commend.
However lowest FREQ by I2C Control was until 148.498024MHz. I guess something wrong setting.

Could you please kindly review customer's schematic and setting file?

LMK05028 Configuration_runConfig,DCO1_FDEV=10000, 2 loop mode.tcs

over 2 years ago

0 Amin Eshraghi over 2 years ago

TI__Expert 6140 points

Hello Yoshimura-san,

What is the range they're looking for? Did it match the target that TICSpro specified?

This will be on ppb scale so large shifts are not going to be possible. Seems like TICSpro does a calculation on what it's capable of and I would like to know whether the results matched that or not.

Regards,

Amin

0 Hironori Yoshimura over 2 years ago in reply to Amin Eshraghi

TI__Intellectual 1820 points

Amin, Customer would like to decrease output freq. Regarding FREQ range, I will double check with customer.
But please check this file first? /cfs-file/__key/communityserver-discussions-components-files/48/LMK05028-Configuration_5F00_runConfig_2C00_DCO1_5F00_FDEV_3D00_10000_2C00_-2-loop-mode.tcs

my Customer would like to adjust clock from 1Hz to 200Mhz range if possible.

Best Regards,
Hironori Yoshimrua

0 Amin Eshraghi over 2 years ago in reply to Hironori Yoshimura

TI__Expert 6140 points

Hello Yoshimura-san,

200 MHz is nowhere near possible. DCO mode is used to make ppb / ppm level shifts on the output. The APLL must remain locked, all that's changed is the numerator value. Max ppm pulling range for the XO is 50 ppm so you wouldn't be able to make changes above that number on the output.

For 200 MHz, the VCO will have to relock which means output clock has to go out.

Please clarify the details of the use case as LMK05028 or really any DPLL device, may not be suited for this application.

Thanks and regards,

Amin

Clock & timing

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LMK05028: Please review customer's schematic, setting