LMX2594: reference oscillator input circuit for phase coherent RF outputs of multiple LMX2594

Hi,

we are working on a test PCB, which should have two phase coherent RF outputs of 8.244 GHz using two LMX2594 - so it's simillar to the reference design TIDA-01410.

Here is the difference: the TIDA-01410 has only one SMA input for the reference oscillator. In our design we want to compare different reference oscillators on board and connectable via SMA. So we want to be able to connect one SMA input and one or more on board oscillators (for example a Crystek CCHD-575 100 MHz HCMOS clock osc.) to the two LMX2594s.

The main question is: which approach would you recommend to map several reference oscillator inputs to the inputs of the two LMX2594? The main concerns are low phase noise of the reference oscillators and phase coherence between the RF outputs.

Is it better to use a completely passive structure like in TIDA-01410 or something like a clock fanout IC with input MUX and (minimum) two outputs? A fanout IC will likely worsen the phase noise and maybe also the phase coherence?

Thank you!

Best regards

Joachim