The FTK3959DFN56 from First Silicon is a MOSFET with Continous Drain Current -56 to -90 A, Drain Source Resistance 3.5 to 7.0 milli-ohm, Drain Source Breakdown Voltage -30 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage -1.2 to -2.2 V. Tags: Surface Mount. More details for FTK3959DFN56 can be seen below.