This part is a kind of semiconductor called K3531-01.

Function of this product has 2SK3531-01.

Manufacturers : Fuji Electric

Image and pinout :

Some of the text within the PDF file :

2SK3531-01 FUJI POWER MOSFET N-CHANNEL SILICON POWER MOSFET Outline Drawings [mm] TO-220AB 200304 Super FAP-G Series Features High speed switching Low on-resistance No secondary breadown Low driving power Avalanche-proof Applications Switching regulators UPS (Uninterruptible Power Supply) DC-DC converters Maximum ratings and characteristicAbsolute maximum ratings (Tc=25°C unless otherwise specified) Item Drain-source voltage Continuous drain current Pulsed drain current Gate-source voltage Repetitive or non-repetitive Maximum Avalanche Energy Maximum Drain-Source dV/dt Peak Diode Recovery dV/dt Max. power dissipation Operating and storage temperature range Symbol Ratings V DS 900 VDSX *5 900 ID ±6 ID(puls] ±24 VGS ±30 IAR *2 6 EAS *1 244 dVDS/dt *4 40 dV/dt *3 5 PD Ta=25°C 2.02 Tc [ ... ]

K3531-01 PDF Datasheet Download