The part appears to be a 3.3V cystal oscillator, with an LVPECL differential output, which oscillates at 30.72MHz.
If you are making your own board based on the demo, you simply need to find an oscillator with those specs. In fact it doesn't even need to be differential or LVPECL, the CDCE62005 supports a wide variety of IO standards for its reference clock.
That particular frequency seems a bit niche, but similar parts do exist - e.g. 530AB30M7200DG (Digikey sell them with MOQ of 50). Alternatively you could try using a different frequency - the CDCE62005 is highly configurable clock generator, so you should be able to adjust the various parameters to get the same output frequencies from a different reference clock.