The IRF640S from Vishay is a MOSFET with Continous Drain Current 11 to 18 A, Drain Source Resistance 0.18 milliohm, Drain Source Breakdown Voltage 200 V, Gate Source Voltage 20 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Surface Mount. More details for IRF640S can be seen below.