I have an ADF5002 evaluation board whose output is fed to the RF port of a mixer, with the IF connected to a filter followed by an amplifier. Recently the ADF5002 just quit working. We are attempting to replace it, but I'm worried as to why it happened. Current best theory is that the later stage amplifier malfunctioned and reflected power back through the IF to the ADF5002, but it doesn't make a lot of sense, since the amplifier max power is probably < 20 dBm, and there is 7 dB loss from the mixer, so it's hard to imagine much power at the output port. How much power would cause a problem there? Are there any tips for protecting this part? I suppose it could also be ESD or maybe just a bad part?