I need to generate a clock of a precise frequency to be used as a time base. The time base frequency will be one of 1.6 GHz, 2 GHz or 2.5 GHz, preferably 2.5 GHz. For 1.6 GHz the ADF4360-4 which has an internal VCO seems like a reasonable solution, but for 2 or 2.5 GHz I was considering the ADF4118 which requires an external VCO such as the ROS-2500-2119. In both cases I was planning to use a 10 MHz - 25 MHz TCXO as a reference. Can anyone suggest a better solution. My main question is regarding interfacing the output of the ADF4360 or the external VCO to an ECL input. The ECL input is one of the inputs of a 2 input AND gate which is rated for a fmax or 3 GHz. Can anyone point me towards a reference design etc. that shows an example of driving an ECL input?