It is packaged using the Tape & Reel (TR) method since it is a clock IC. The uPs/uCs/Peripheral IC clock generator incoporates is CLOCK GENERATOR, PROCESSOR SPECIFIC.
SI5351A-B09778-GTR Features
SI5351A-B09778-GTR Applications
There are a lot of Silicon Labs SI5351A-B09778-GTR Clock Generators applications.