IRF540NPBF

The IRF540NPBF from Infineon Technologies (formerly International Rectifier) is a 100V N-channel power MOSFET utilizing the advanced HEXFET planar cell structure to achieve 44mΩ maximum on-resistance at VGS=10V. The device is rated for 33A continuous drain current at TC=25°C and 130W power dissipation, making it one of the most widely used general-purpose power MOSFETs in the industry. The 2.0V to 4.0V gate threshold makes it compatible with 5V logic-level gate drive, though 10V gate drive is recommended for minimum RDS(on). The device is fully avalanche rated, meaning it can withstand repetitive energy pulses from inductive loads without external clamp circuits. The TO-220AB package provides easy through-hole mounting with heatsink attachment capability. The PBF suffix indicates the lead-free (Pb-free) version.

The IRF540NPBF is an enhancement-mode N-channel MOSFET. When VGS exceeds the threshold voltage (2-4V), an inversion layer forms under the gate oxide, creating a conductive channel between drain and source. At VGS=10V, the channel is fully enhanced, and the on-resistance drops to 44mΩ or less. The power dissipation is I²×RDS(on); at 10A, this is only 4.4W (10² × 0.044), allowing significant current without excessive heating. However, at higher currents (20A+), careful thermal management is essential: P = 20² × 0.044 = 17.6W requires a heatsink with RθSA < (175 – Tamb)/17.6 – 1.15°C/W. The body diode (inherent PN junction from source to drain) conducts when VDS goes negative, making the device suitable for half-bridge and H-bridge topologies where freewheeling current flows through the body diode during dead time. The 71nC total gate charge determines the drive power: P_drive = Qg × VGS × f_sw. At 100kHz switching, P_drive = 71nC × 10V × 100kHz = 71mW. The 11ns turn-on delay and 35ns rise time enable switching frequencies up to several hundred kHz in hard-switched applications.

IRF540NPBF follows the standard TO-220-3 MOSFET pinout: Pin 1 = Gate, Pin 2 = Drain (tab), Pin 3 = Source. The metal tab on the back of the package is electrically connected to Drain (Pin 2) and must be electrically isolated from the heatsink when the heatsink is not at drain potential, using a mica or silicone insulator and a shoulder washer. For low-side switching applications (Source to GND), the tab can be directly mounted to a grounded heatsink. The Gate is ESD-sensitive — handle with proper antistatic precautions. Gate charge of 71nC requires adequate gate driver capability for fast switching to minimize transition losses.

• DC Motor Driver: Low-side switch with VGS=10V gives 44mΩ; at 10A motor current, conduction loss is only 4.4W
• H-Bridge: Four IRF540NPBF in full-bridge configuration drive bidirectional DC motors at up to 24V
• Load Switch: 100V rating allows switching 48V telecom rails; gate pull-down ensures off-state during MCU reset
• SMPS Switch: 71nC gate charge supports 100kHz+ switching; 130W rating handles flyback/forward converter primary
• Audio Amplifier: Linear operation with 175°C Tj max; heatsink required for class-AB output stages

IRF540NPBF is a 100V/33A N-channel MOSFET from Infineon in TO-220 with 44mΩ RDS(on). The IRL540N provides logic-level 100V/28A for 5V gate drive. The FQP30N06L provides 60V/30A with 35mΩ and logic-level drive. The IRF640N offers 200V/18A for higher voltage. For surface-mount, IRF540NSPBF provides the same in D2PAK. Complementary P-channel: IRF9540NPBF (-100V/-19A). For synchronous rectification, IRFB4110 offers 100V/180A with 3.7mΩ.