We currently have 3 LMX2594 devices on a custom PCB. We are having a problem getting only one of them to lock. Our Ref frequency is 10MHz and our output frequency is 300MHz or 250MHz, depending on the required functionality.
Our configuration is as shown (same as the Xilinx ZCU111).
All 3 circuits have the same component layout. When we reduce the charge pump frequency to 3mA for this one device, it is able to lock (on most boards). If we increase the output frequency (reduce FVCO to 8GHz), it loses it's lock even when it's set to charge pump current on 3mA. Do you have any suggestions as to what we could look at to determine what the issue is?
