The S4101 from ROHM Semiconductor is a MOSFET with Continous Drain Current 55 A, Drain Source Resistance 40 to 60 Milliohm, Drain Source Breakdown Voltage 1200 V, Gate Source Voltage -4 to 22 V, Gate Source Threshold Voltage 2.7 to 5.6 V. Tags: Die. More details for S4101 can be seen below.