The NXP MK22FN256CAH12R is an ARM Cortex-M4 microcontroller clocked at 120 MHz, with 256 KB Flash and 48 KB SRAM. That core speed is enough for real-time control loops, USB OTG host/device stacks, and moderate DSP workloads. The 48 KB SRAM handles two or three active USB endpoints plus a couple of moderate data arrays; if your application needs a large frame buffer or multiple DMA descriptors, budget the RAM carefully.
The 64-WLCSP package (3.35 × 3.32 mm) saves board area but demands a controlled assembly process — fine-pitch stencil, proper underfill for mechanical reliability, and X-ray inspection for solder-joint integrity. Not a hand-solder part.