The Si4128DY from Vishay is a MOSFET with Continous Drain Current 10.9 A, Drain Source Resistance 20 to 30 milliohm, Drain Source Breakdown Voltage 30 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1 to 2.5 V. Tags: Surface Mount. More details for Si4128DY can be seen below.