A clock integrated circuit is packaged in a Tape & Reel (TR)-shaped package because it is for use as a clock. The uPs/uCs/Peripheral IC clock generator incoporates is CLOCK GENERATOR, PROCESSOR SPECIFIC.
SI5351A-B05517-GTR Features
SI5351A-B05517-GTR Applications
There are a lot of Silicon Labs SI5351A-B05517-GTR Clock Generators applications.