LMX2582: lock problem

see attached file.test1.tcs

Hi Jac,

The configuration looks good.

Are you using your loop filter or using eval board default loop filter?

Is the reference clock a TCXO with clipped sine wave output? How did you connect it to the synthesizer?

I can share the circuit, pls help to check

Hi Jac,

OSCin schematic is fine, if you share this signal with other device via C329, make sure the voltage is still sufficient at OSCIN_P pin.

The reason of unlock is probably due to the loop filter.

According to you configuration and loop filter, phase margin of the loop is 19.38deg, which means the loop is not stable.

You can do a quick check by increasing the charge pump gain. Below setting will bring the phase margin to 46.6deg.