This part is a kind of semiconductor called C3552.
Function of this product has 2SC3552.
Manufacturers : Sanyo Semiconductor Corporation
Image and pinout :
Some of the text within the PDF file :
Ordering number:EN1597C NPN Triple Diffused Planar Silicon Transistor www.DataSheet4U.com 2SC3552 800V/12A Switching Regulator Applications Features · High breakdown voltage and high reliability. · Fast switching speed (tf : 0.1µs typ). · Wide ASO. · Adoption of MBIT process. Package Dimensions unit:mm 2022A [2SC3552] Specifications Absolute Maximum Ratings at Ta = 25˚C Parameter Collector-to-Base Voltage Collector-to-Emitter Voltage Emitter-to-Base Voltage Collector Current Collector Current (Pulse) Base Current Collector Dissipation Junction Temperature Storage Temperature Symbol VCBO VCEO VEBO IC ICP IB PC Tj Tstg Tc=25˚C PW≤300µs, Duty Cycle≤10% 1 : Base 2 : Collector 3 : Emitter SANYO : TO-3PB Conditions Ratings 1100 800 7 12 30 6 150 150 –55 to +150 Unit V V V [ ... ]