The FDMS0309AS from onsemi is a MOSFET with Continous Drain Current 49 A, Drain Source Resistance 3.5 milliohm, Drain Source Breakdown Voltage 30 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 3 V. Tags: Surface Mount. More details for FDMS0309AS can be seen below.