LMX2572EVM: Check the Phase Noise at 100Hz

Louis Han15

Genius 4680 points

Part Number: LMX2572EVM
Other Parts Discussed in Thread: LMX2594EVM

Hello

I tested the Phase noise in TICS default mode.

However, the test results were check to be different from the specifications.

Test Data

Spec Data

There is a difference of about 17dBc/Hz at 100Hz.

Test conditions were the same as in the User Guide.

1. Why are the test results different from the specifications?

2. How can I check the same result as the specifications?

3. Why is the purchased LMX2572EVM different from the BOM in the user guide? (refer below)

user guide BOM : R25 - 51ohm, R30 - 51ohm, R4_LF - 0 ohm, R4_LF - 330 ohm

purchased LMX2572EVM : R25 - OPEN, R30 - OPEN, R4_LF - 18 ohm, R4_LF - 68 ohm

Best Regards.

over 4 years ago

0 Noel Fung over 4 years ago

TI__Guru* 89540 points

Hi Louis,

The 100Hz phase noise could be due to test equipment or due to the 100MHz clock generator in Reference Pro board. We use E5052 to measure the phase noise.

For the component difference, I think our EVM vendor made a mistake. From the measured loop bandwidth, I think the LMX2572EVM loop filter was populated with the LMX2594EVM loop filter.

Could you tell us where did you purchase the EVM from? Could you also provide some information of the board so that I can track back to when and which vendor build the board?