The Si4838BDY from Vishay is a MOSFET with Continous Drain Current 34 A, Drain Source Resistance 2 to 4 milliohm, Drain Source Breakdown Voltage 12 V, Gate Source Voltage -8 to 8 V, Gate Source Threshold Voltage 0.4 to 1 V. Tags: Surface Mount. More details for Si4838BDY can be seen below.