Does ADI have 6GHz PLL solution for under 1ns lock time? I have found ADF5610. but it's lock time about 100us.
It is interesting problem. If you want lock it t<1ns, in means max. number of 6GHz VCO cycles n<6. Within 5 VCO cycles the tuning voltage must be stable. This correspond also to PLL BW e.g. 1GHz. I think the lock time may decrease if you multiply the VCO output e.g. 40x to 240GHz, but to reach 1ns it is really challenging.