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spann
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Registered: ‎08-06-2019

RFSOC LMK04208 clock source

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Hi all:

We want to change  LMK04208 input clok source from Clkin0 to Clkin1

Can you help me how to configure it ?

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klumsde
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Registered: ‎04-18-2011

Hi @spann 

If you pull out the jumper J110 this will power off the TCXO 

I think you may have to program the LMK to take the PLL input from the CLKIN1 input

You can download the ticsPro SW and load the profile you would normally use then select the input from the other source. ticspro_lmk_sma.JPG

 

You should check with the TI docs here though to be sure this is needed. 

 

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pthakare
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Registered: ‎08-08-2017

Hi @spann 

This is purely LMK04208 on board  PLL issue and your best bet is to check this with Texas Support.

As far as i know  " Which reffernece to use is deviced by  external pins Status_CLKin0 and Status_CLKin1 input of LMK04208"

LMK04208 datasheet have detailed description around this.

 

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drjohnsmith
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Registered: ‎07-09-2009

Try this
http://www.ti.com/lit/ds/symlink/lmk04208.pdf
look at section 8.1.2

 

you dont say what your board is, 

   but most / all xilinx eval boards have great docs that explain this sort of thing,

 

e.g.

https://www.xilinx.com/support/documentation/boards_and_kits/zcu111/ug1271-zcu111-eval-bd.pdf

 

<== If this was helpful, please feel free to give Kudos, and close if it answers your question ==>
klumsde
Moderator
Moderator
733 Views
Registered: ‎04-18-2011

Hi @spann 

If you pull out the jumper J110 this will power off the TCXO 

I think you may have to program the LMK to take the PLL input from the CLKIN1 input

You can download the ticsPro SW and load the profile you would normally use then select the input from the other source. ticspro_lmk_sma.JPG

 

You should check with the TI docs here though to be sure this is needed. 

 

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klumsde
Moderator
Moderator
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Registered: ‎04-18-2011

Reading the doc from @drjohnsmith 

There is some suggestion that if one input is gone it can automatically switch to the other one. 

So powering off the TCXO may be enough here. 

Cheers, 

Keith 

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