This part is a kind of semiconductor called IRF550A.

Function of this product has Advanced Power MOSFET.

Manufacturers : Fairchild Semiconductor

Image and pinout :

Some of the text within the PDF file :

Advanced Power MOSFET FEATURES Avalanche Rugged Technology Rugged Gate Oxide Technology Lower Input Capacitance Improved Gate Charge Extended Safe Operating Area 175 C Operating Temperature Lower Leakage Current : 10 µA (Max.) @ VDS = 100V Lower RDS(ON) : 0.032 Ω (Typ.) Ο IRF550A BVDSS = 100 V RDS(on) = 0.04 Ω ID = 40 A TO-220 1 2 3 1.Gate 2. Drain 3. Source Absolute Maximum Ratings Symbol VDSS ID IDM VGS EAS IAR EAR dv/dt PD TJ , TSTG TL Characteristic Drain-to-Source Voltage Continuous Drain Current (TC=25 C) Ο Value 100 40 28.3 1 O Ο Units V A A V mJ A mJ V/ns W W/ C Ο Continuous Drain Current (TC=100 C) Drain Current-Pulsed Gate-to-Source Voltage Single Pulsed Avalanche Energy Avalanche Current Repetitive Avalanche Energy Peak Diode Recovery dv/dt Total Power Dissipatio [ ... ]

IRF550A PDF Datasheet Download