The Si4630DY from Vishay is a MOSFET with Continous Drain Current 40 A, Drain Source Resistance 2 to 3 milliohm, Drain Source Breakdown Voltage 25 V, Gate Source Voltage -20 to 16 V, Gate Source Threshold Voltage 1 to 2.2 V. Tags: Surface Mount. More details for Si4630DY can be seen below.