LMX2820EVM: datasheet phase noise performance

Adrian Liu

Part Number: LMX2820EVM

Hi Team,

Customer are using lmx2820EVM for evaluating work, they follow the instructions in the "User’s Guide LMX2820EVM Evaluation Module" and setup the EVM board, but the actual test result is worse than the D/S.

A VCXO is used as reference clock. Phase noise shown as below:

Default 6GHz output test from customer's EVM attached as below:(already change the C31 from 1µF to 10µF, and C29 from 0.47µF to 1µF)

Default 6GHz output test from datasheet as below:

Can u share the phase noise test result of the reference clock and 6G default output on your setup?

Thanks

Adrian

over 2 years ago

0 Noel Fung over 2 years ago

TI__Guru** 108850 points

Hi Adrian,

This is the plot from a EVM in the lab. I have change C31 to 10µF, this is the correct value for this capacitor. I have also change C29 to 1µF to reduce in-band noise.

Reference clock came from SMA100B.

0 Adrian Liu over 2 years ago in reply to Noel Fung

TI__Intellectual 2645 points

Hi Noel,

Thanks for your quick reply.

It seems that the results are very close to the specifications, but there appears to be a difference of 1-2dB at the near end. What could be the reason for this? Could it be due to the reference source?

Adrian

0 Noel Fung over 2 years ago in reply to Adrian Liu

TI__Guru** 108850 points

Hi Adrian,

Probably, I think datasheet data was taken with a Wenzel clock.

Clock & timing

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LMX2820EVM: datasheet phase noise performance