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  • TI Thinks Resolved

LMK00338: No Output Signal, Input seems good

Prodigy 30 points

Replies: 3

Views: 44

Part Number: LMK00338

We use the clock divider in a very simple way, input 135MHz seems good but we have no output signal. Some ideas?

  • Hi Sven,

    The schematic looks OK. Do you have the 50ohm terminations to GND on the output pins?

    I recommend to add decoupling capacitors but you should be seeing an output.

    Have you checked using another device? Have you observed this on other boards?

    Kind regards,
    Lane

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  • In reply to Lane Boyd:

    Hi, 

    thanks for the quick respond. 

    We use 100nF decoupling capacitors, but they are placed on the fpga-inputs, so you can not see it in this partial view. 

    I tested 3 buffers on one board with the same results. 

    So i ordered 20 new chips and a evalboard from digikey, this will take a few days... 

    kind regards 

    Sven 

  • In reply to Lane Boyd:

    Hi Lane,

    we checked the board again and the 50Ohms on the output made it work. Important notice put the 50Ohm first and then the decoupling caps.

    We thought the 50ohm is for reflections but instead it is HCSL output ...

    kind regards,

    Sven

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