The NCP81296MNTXG is an onsemi SENSEFET electronic fuse rated for a continuous 50 A output from a 4.5 V to 18 V input rail. That 50 A figure is the current the internal FET can carry in the on-state — it is not a surge or pulse rating, so the BOM needs to budget the full load current below this ceiling with derating for ambient temperature. High-side sensing means the voltage drop across the internal sense element is measured on the input side of the load — the part regulates current by comparing that drop to an internal reference. The ±6 % accuracy tells you the actual current limit will fall within 47 A to 53 A at the setpoint, which matters when sizing the downstream PCB trace and connector for worst-case fault current.
The 0.5 mm pitch QFN footprint is routable on a 4-layer board without microvias. CT is for prototyping or low-volume builds where the full reel quantity is not needed.