This part is a kind of semiconductor called 2SK4059TK.
Function of this product has Silicon N Channel Junction Type.
Manufacturers : Toshiba Semiconductor
Image and pinout :
Some of the text within the PDF file :
2SK4059TK TOSHIBA Field Effect Transistor Silicon N Channel Junction Type 2SK4059TK For ECM • Application for compact ECM 0.22±0.05 1.2±0.05 0.8±0.05 0.32±0.05 3 2 0.1±0.05 Unit: mm Absolute Maximum Ratings (Ta=25°C) 0.45 0.45 1.4±0.05 Characteristic Symbol VGDO IG PD Tj Tstg Rating -20 10 100 125 −55~125 Unit V mA mW °C Gate-Drain voltage Gate Current Drain power dissipation (Ta = 25°C) Junction Temperature Storage temperature range Note: Using continuously under heavy loads (e.g. the application of high temperature/current/voltage and the significant change in temperature, etc.) may cause this product to decrease in the reliability significantly even if the operating conditions (i.e. operating temperature/current/voltage, etc.) are within the a [ ... ]