The FDT439N from onsemi is a MOSFET with Continous Drain Current 6.3 A, Drain Source Resistance 38 to 72 milliohm, Drain Source Breakdown Voltage 30 V, Gate Source Voltage -8 to 8 V, Gate Source Threshold Voltage 1 V. Tags: Surface Mount. More details for FDT439N can be seen below.