The IXFA4N85X from Littelfuse is a MOSFET with Continous Drain Current 3.5 A, Drain Source Resistance 2500 Milliohm, Drain Source Breakdown Voltage 850 V, Gate Source Voltage -30 to 30 V, Gate Source Threshold Voltage 3 to 5.5 V. Tags: Surface Mount. More details for IXFA4N85X can be seen below.