The TSM2318CX from Taiwan Semiconductor is a MOSFET with Continous Drain Current 3.9 A, Drain Source Resistance 36 to 62.5 milliohm, Drain Source Breakdown Voltage 40 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1 to 3 V. Tags: Surface Mount. More details for TSM2318CX can be seen below.