The IRF1404PBF is an N-channel power MOSFET from Infineon (formerly International Rectifier) in TO-220, rated at 40V VDSS, 202A ID, and 4mOhm RDS(on) at VGS=10V. This is an extreme low-RDS(on) device designed for high-current, low-voltage switching applications. The 4mOhm RDS(on) is achieved using Infineon’s stripe trench MOS technology: the gate electrode is formed as vertical trenches in the silicon, with the current flowing vertically through thousands of parallel MOSFET cells. At ID=100A, the conduction loss is P = I2 x RDS(on) = 1002 x 0.004 = 40W, requiring a substantial heatsink. The TO-220 package provides 0.5C/W junction-to-case thermal resistance; with a 0.5C/W heatsink, the thermal budget at 100A is: Tj = 40W x (0.5 + 0.5 + 0.1) = 44C above ambient, well within the 175C maximum. The gate charge is Qg = 160nC at VGS=10V, requiring a gate driver capable of sourcing/sinking at least 1.6A for 100ns switching times. The switching energy (Eon + Eoff) is approximately 50uJ at 100A, producing 5W of switching loss at 100kHz. The device is commonly used in parallel pairs for even lower RDS(on): two IRF1404 in parallel provide 2mOhm effective resistance. The internal freewheeling body diode has trr = 100ns, making it suitable for half-bridge motor drives without external Schottky diodes. The -PBF suffix specifies lead-free. Applications include: DC motor drives, battery disconnect switches, welding machine inverters, and automotive 12V power switching.