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LMX2820EVM: LMX2820EVM Phase Noise

Part Number: LMX2820EVM
Other Parts Discussed in Thread: USB2ANY, LMX2820

I am testing the Evaluation Module LMX2820EVM at 6 GHz and I have not been able to confirm the phase noise specification ( page 7 of the User Guide).

The phase noise is higher by 4 to 5dB from 1khz to 100Khz.

At 1Mhz it is only 1db higher and in spec at higher offsets.

I am using a low noise 100MHz "RF Plate" from Wenzel Associates. The 100MHz reference power I used is 12dBm  The phase noise data measurement has been validated on 2 different set-ups.

The phase noise has not improved by using the input Doubler and Fpd 200MHz.

Any suggestion?


  • Mark,

    A few things that can sometimes help:

    • Unplug the USB2ANY and see if anything changes
    • Check if it's a power supply issue - we've seen a few times where the power supply introduces broadband noise

    Are you using the default EVM profile? Can you save a copy of the profile you load whenever trying to measure the phase noise and upload it to E2E for our review? I can load it on our LMX2820 with our Wenzel and we can attempt to correlate out any setup issues.


    Derek Payne

  • Mark,

    We have the same problem.

    I posted it in "RE: LMX2820EVM: Phase Noise" title, but it has not been resolved.

    It seems we have no choice but to wait for answers on the India site.

  • Hi Mark,

    Thank you for your patience, we have been trying to get some time in the lab to look into this issue, we are also very eager to resolve this problem asap, but as you may know, the situation in India site is not ideal. 

    Stay tuned, we will certainly let you know once we have a solution. Thank you.