The STN3N45K3 from STMicroelectronics is a MOSFET with Continous Drain Current 0.6 A, Drain Source Resistance 3300 to 4000 Milliohm, Drain Source Breakdown Voltage 450 V, Gate Source Voltage -30 to 30 V, Gate Source Threshold Voltage 3 to 4.5 V. Tags: Surface Mount. More details for STN3N45K3 can be seen below.