The STD5N52U from STMicroelectronics is a MOSFET with Continous Drain Current 4.4 A, Drain Source Resistance 1250 to 1500 Milliohm, Drain Source Breakdown Voltage 525 V, Gate Source Voltage -30 to 30 V, Gate Source Threshold Voltage 3 to 4.5 V. Tags: Surface Mount. More details for STD5N52U can be seen below.