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LMX2595EVM: lmx2595EVM

Lee Juheun
Prodigy 10 points
Part Number: LMX2595EVM


I'm using TICS Pro tool and I'm following the user's guide. Since we wanted a 16GHz output, we set it up as shown. As a result, 16 GHz was output. but, If you zoom in on the output scale, it will shake in units of 100 Hz. Is it because the PLL is not locked? or is it normal to shake about 100 Hz? We will attach pictures of the output and GUI settings.

I attached a photo file.

Image.zip

  • 0
    TI__Guru** 109470 points

    Hi Lee,

    I think there are two possibilities:

    1. The drift is due to the on-board XO. From 100MHz input to 16000MHz output, the multiplication factor is 160. If the XO drifts 1Hz, then you will see 160Hz drift at the output. I seldom use the on-board XO, I am not sure if this is the root cause, I will check it with an EVM.

    2. if you did not modify the original loop filter, you have significant reduced the loop bandwidth and phase margin because the fpf is just 5MHz (default TICS Pro setting is fpd=200MHz). Could you try again with a much higher fpd, for example, 100MHz?