The S4603 from ROHM Semiconductor is a MOSFET with Continous Drain Current 43 A, Drain Source Resistance 36 to 72 Milliohm, Drain Source Breakdown Voltage 1200 V, Gate Source Voltage -4 to 21 V, Gate Source Threshold Voltage 2.8 to 4.8 V. Tags: Die. More details for S4603 can be seen below.