QFET? N-Channel MOSFET, over 31A, Fairchild Semiconductor Fairchild Semiconductor’s new QFET? planar MOSFETs use advanced, proprietary technology to offer best-in-class operating performance for a wide range of applications, including power supplies, PFC (Power Factor Correction), DC-DC Converters, Plasma Display Panels (PDP), lighting ballasts, and motion control. They offer reduced on-state loss by lowering on-resistance (RDS(on)), and reduced switching loss by lowering gate charge (Qg) and output capacitance (Coss). By using advanced QFET? process technology, Fairchild can offer an improved figure of merit (FOM) over competing planar MOSFET devices.