Hi, I am currently using the ADF4360-9 to generate an LO ref in the range 146-152 MHz. My phase noise requirements are quite strict so have ended up running the VCO at double this and using the Divout f/2 output to get a slight improvement in noise performance. Am curious if there are any other synthesizer ICs with integrated VCOs that offer slightly better phase noise performance? Or would a topology with an external VCO be a better strategy to minimize phase noise? Also are there any designs which use an external varactor diode to reduce noise?
Many thanks in advance,