FQB3N40TM

Single FETs, MOSFETs Overview

The FQB3N40TM is an N-channel enhancement mode power MOSFET from the QFET series, manufactured by Fairchild Semiconductor. It features a drain-source breakdown voltage (VDSS) of 400V and a continuous drain current (ID) of 2.5A at 25°C. The device utilizes D2PAK surface-mount packaging with an isolated case connection. Key electrical characteristics include a maximum on-resistance (RDS(on)) of 2.5Ω at VGS=10V and a gate threshold voltage (VGS(th)) typically ranging from 2V to 4V. It integrates a built-in body diode for inductive load switching applications.

Single FETs, MOSFETs Feature Summary

• High-voltage N-channel construction optimized for efficient power switching
• Integrated fast-recovery body diode for inductive load protection
• D2PAK flange-mount package providing robust thermal dissipation

Single FETs, MOSFETs Applications

• High-voltage DC-DC converter circuits
• Inductive load switching drivers
• Power supply output stages

Single FETs, MOSFETs Procurement Notes

Verify the manufacturer source carefully as Fairchild's discrete semiconductor business was acquired by ON Semiconductor. Ensure the component matches the original Fairchild specifications rather than generic equivalents. Confirm the presence of the specific QFET branding and D2PAK marking codes to distinguish it from other 400V MOSFET variants in the market.

Single FETs, MOSFETs Selection Notes

Select this component when a 400V rating is required with moderate current handling capabilities around 2.5A. The D2PAK package is suitable for board-level mounting where thermal performance is critical. Consider the RDS(on) value relative to the application's conduction loss requirements and ensure the gate drive voltage supports the specified threshold levels for full enhancement.

Single FETs, MOSFETs Part Context

This part belongs to the QFET family, representing Fairchild's advanced planar MOSFET technology designed for high reliability and low on-resistance. The FQB3N40TM serves as a discrete power switch within broader power management systems, often replacing older TO-220 designs with more compact surface-mount solutions.

Single FETs, MOSFETs Replacement Considerations

Check for direct cross-reference part numbers such as FQD6N40CTM or FQB5N80TM depending on specific current and voltage margin requirements. Verify pinout compatibility and thermal resistance values before substituting.