Hello,
I have implemented an LMX2571 on a custom PCB, and this one has been placed close to an LTC3119 Buck-Boost converter. This converter is set to work at 500kHz.
Some tests show that while the LTC3119 converter is power on, the LMX2571 have heavily perturbated RF output : peak frenquency is shifted of +10kHz and the spectrum is flattened. When the LTC3119 is off, we have the desired behaviour (frequency stability, constellation, ...)
As I guess some internal part (Phase loop, VCO, ...) are pertubated by this DC/DC converter, I would like to know if you have any elements about immunity of the LMX2571, or specific point of attention I may have in the layout using this part.
Don't hesitate if you need more information/details about the design to offer better answer.
Thank you,
Benjamin.