This part is a kind of semiconductor called 4N40.

Function of this product has N-Channel MOSFET Transistor.

Manufacturers : Inchange Semiconductor

Image and pinout :

Some of the text within the PDF file :

INCHANGE Semiconductor isc N-Channel MOSFET Transistor isc Product Specification 4N40 ·FEATURES ·Drain Current ID= 4A@ TC=25℃ ·Drain Source Voltage- : VDSS= 400V(Min) ·Static Drain-Source On-Resistance : RDS(on) = 2.1Ω(Max) ·Fast Switching ·APPLICATIONS ·Switch mode power supply. ·ABSOLUTE MAXIMUM RATINGS(Ta=25℃) SYMBOL PARAMETER VALUE UNIT VDSS VGS Drain-Source Voltage Gate-Source Voltage-Continuous 400 ±30 V V ID Drain Current-Continuous 4A IDM Drain Current-Single Plused 10 A PD Total Dissipation @TC=25℃ 75 W Tj Max. Operating Junction Temperature 150 ℃ Tstg Storage Temperature -55~150 ℃ ·THERMAL CHARACTERISTICS SYMBOL PARAMETER Rth j-c Thermal Resistance, Junction to Case MAX UNIT 2.0 ℃/W isc website：www.iscsemi.cn 1 isc & iscsemi is [ ... ]

4N40 PDF Datasheet Download