We received and fitted samples of ADF4351, in place of the ADF4350 (which has rather a slow frequency change for our requirements)
Although the board with the new part works properly (i.e. appears to lock to the required frequency), the lock detect ouput stays at ground when locked. We have also checked the Mux'd lock detector output, and this also does not change state when in lock. Three known working boards have been fitted with the ADF4351, and all show the same problem.
We cannot find any information in the latets data sheet (PrD) that might help us with this problem, do you have any further details please ?