This part is a kind of semiconductor called 2SK3296.
Function of this product has MOS FIELD EFFECT TRANSISTOR.
Manufacturers : NEC
Image and pinout :

Some of the text within the PDF file :
DATA SHEET MOS FIELD EFFECT TRANSISTOR 2SK3296 SWITCHING N-CHANNEL POWER MOS FET INDUSTRIAL USE DESCRIPTION The 2SK3296 is N-Channel MOS FET device that features a low on-state resistance and excellent switching characteristics, designed for low voltage high current applications such as DC/DC converter with synchronous rectifier. ORDERING INFORMATION PART NUMBER 2SK3296 2SK3296-S 2SK3296-ZK 2SK3296-ZJ PACKAGE TO-220AB TO-262 TO-263(MP-25ZK) TO-263(MP-25ZJ) FEATURES • 4.5 V drive available • Low on-state resistance RDS(on)1 = 12 mΩ MAX. (VGS = 10 V, ID = 18 A) • Low gate charge QG = 30 nC TYP. (ID = 35 A, VDD = 16 V, VGS = 10 V) • Built-in gate protection diode • Surface mount device available ABSOLUTE MAXIMUM RATINGS (TA = 25°C) Drain to Source Voltage (VGS = 0 V) Gate t [ ... ]
2SK3296 PDF Datasheet Download
