The Si3443DDV from Vishay is a MOSFET with Continous Drain Current 4 A, Drain Source Resistance 39 to 90 milliohm, Drain Source Breakdown Voltage -20 V, Gate Source Voltage -12 to 12 V, Gate Source Threshold Voltage -0.6 to -1.5 V. Tags: Surface Mount. More details for Si3443DDV can be seen below.