Hello,
I am designing ADC interface prototype as my project and I am interested in LMK62E0-156M; LVPECL output (I'm also considering higher frequency ones as well).
The ADC requires very low jitter, so I think LMK62E0 would be one of the best solution as the ADC clock source. When I see the reference design in the ADC datasheet, the clock circuitry looks like below figure.
Of course, the Y1 in the reference design was a general XO and I just configured it by LMK62E0-156M without any consideration. From the above design, my question is whether I really need the transformer.
The ADC offers a common voltage reference to the clock signal, so the clock must be AC coupled - which can be achieved by AC coupling capacitors (C57 & C58 in above figures). In that sense, I have a lack of understanding what the role of the transformer is in above configuration.
(1) If I solely use LMK62E0-156M's LVPECL output only with the termination resistors (R20 & R21) and coupling capacitors (C54 & C55) to provide ADC clock source, could there be any problem?
(2) If Q1 is possible, which configuration would be beneficial to provide the lowest jitter? (With or without transformer)
For some comments or recommendations, it would be very much appreciate.
