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LMX2595EVM: Inductor pullup

Enrico Silvestri

Prodigy 20 points

Part Number: LMX2595EVM
Other Parts Discussed in Thread: LMX2595

Hello,

I'm testing the LMX2595 PLL evaluation board. By default the output pins pull-up is with a 50 Ohm resistor. I need to measure the maximum output power of the PLL with the inductor-type pull-up. How do I need to modify the evaluation board to do that ? Could I just substitute the 50 Ohm resistors with the inductors ?

0 Noel Fung 8 days ago

TI__Guru** 121670 points

Hi There,

Correct, replace the 50ohm resistors with inductors.

0 Enrico Silvestri 7 days ago in reply to Noel Fung

Prodigy 20 points

Hey,

do you have any tips on how to choose the value for the inductor ? And, one more thing, do I need to remove the inductor L1 and the capcitor C6 ?

thank you.

0 Noel Fung 7 days ago in reply to Enrico Silvestri

TI__Guru** 121670 points

Hi There,

The inductor we used in the datasheet is 1nH, you may need to use a different value if you have a specific frequency of interest.

In LMX2615 datasheet, we have some discussion on the inductor.

L1 is a RF choke while C6 is an AC-short.

L1 may not be necessary but C6 must present to short the pull-up components to ground.