The S4001 from ROHM Semiconductor is a MOSFET with Continous Drain Current 70 A, Drain Source Resistance 30 to 39.6 Milliohm, Drain Source Breakdown Voltage 650 V, Gate Source Voltage -4 to 22 V, Gate Source Threshold Voltage 2.7 to 5.6 V. Tags: Die. More details for S4001 can be seen below.