I have used HMC833 in my receiver design. It is only locking with the initial values for registers in Init file given in the Eval software and the LD pin goes high. The default frequency is 3 GHz. By changing the frequency around 3 GHz it is only locking one step below or above 3 GHz. (2.95 and 3.05 ! GHz is OK) But when I set frequency to 2.9 GHz it does not lock any more and the output goes around 2.96 GHz and it is also unstable. I have tried to calculate registers value for the other frequencies with the Eval software but unfortunately it is not working with out Eval board!