What this clock conditioner does on a high-speed board
The Texas Instruments LMK04002BISQ/NOPB is a low-noise clock jitter conditioner built around a PLL core. It accepts LVCMOS, LVDS, or LVPECL reference inputs and delivers cleaned-up LVCMOS or LVPECL outputs across a 2:7 input-to-output ratio.
Supply and temperature — the operating envelope
No official second-source alternate is listed, but the base product number LMK04002 covers a family of jitter-cleaning PLLs with similar footprint and pinout across speed grades — useful for a second-sourcing qualification if volume warrants it.