The STD4LN80K5 from STMicroelectronics is a MOSFET with Continous Drain Current 3 A, Drain Source Resistance 2100 to 2600 Milliohm, Drain Source Breakdown Voltage 800 V, Gate Source Voltage -30 to 30 V, Gate Source Threshold Voltage 3 to 5 V. Tags: Surface Mount. More details for STD4LN80K5 can be seen below.