This part is a kind of semiconductor called IRF643.

Function of this product has N-Channel Mosfet Transistor.

Manufacturers : Inchange Semiconductor

Image and pinout :

Some of the text within the PDF file :

INCHANGE Semiconductor isc N-Channel Mosfet Transistor ·FEATURES ·Low RDS(on) ·VGS Rated at ±20V ·Silicon Gate for Fast Switching Speed ·Rugged ·Low Drive Requirements isc Product Specification IRF643 ·DESCRITION ·Designed especially for high voltage,high speed applications, such as off-line switching power supplies , UPS,AC and DC motor controls,relay and solenoid drivers. ·ABSOLUTE MAXIMUM RATINGS(Ta=25℃) SYMBOL PARAMETER VALUE UNIT VDSS VGS Drain-Source Voltage Gate-Source Voltage-Continuous 150 ±20 V V ID Drain Current-Continuous 16 A IDM Drain Current-Single Plused 64 A PD Total Dissipation @TC=25℃ 125 W Tj Max. Operating Junction Temperature -55~150 ℃ Tstg Storage Temperature -55~150 ℃ ·THERMAL CHARACTERISTICS SYMBOL PARAMETER MAX UNIT Rth [ ... ]

IRF643 PDF Datasheet Download