IRFR420B Datasheet – 500V, MOSFET, Transistor ( PDF )

Part Number: IRFR420B

Function: 500V, N-Channel MOSFET

Package: D-PAK, I-PAK Type

Manufacturer: Fairchild Semiconductor

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Description

IRFR420B is a 500V N-channel enhancement-mode power MOSFET based on planar DMOS technology, optimized for high-voltage switching applications such as SMPS, PFC circuits, and electronic ballasts. It features low gate charge, fast switching speed, and मजबूत avalanche capability, making it suitable for efficient high-frequency power conversion.

These N-Channel enhancement mode power field effect transistors are produced using Fairchild’s proprietary, planar, DMOS technology.

This advanced technology has been especially tailored to minimize on-state resistance, provide superior switching performance, and withstand high energy pulse in the avalanche and commutation mode. These devices are well suited for high efficiency switch mode power supplies, power factor correction and electronic lamp ballasts based on half bridge.

Features

• Drain-source voltage: 500V
• Continuous drain current: 2.3A
• Low R_DS(on): 2.6Ω @ V_GS = 10V
• Low gate charge: ~14 nC (typical)
• Low reverse transfer capacitance (C_rss): ~10 pF
• Fast switching characteristics
• High avalanche energy capability (100% tested)
• Improved dv/dt ruggedness

Pinout

Absolute Maximum Ratings (Ta = 25°C)

Design Notes

• Gate drive voltage typically 10–15V recommended for full enhancement
• Use proper gate resistor to control switching speed and EMI
• Snubber or clamp circuit required in inductive switching (flyback, ballast)
• Thermal design is critical due to relatively low Pd (2.5W in DPAK)
• Ensure adequate PCB copper area for heat dissipation
• Check SOA under high V_DS and pulsed current conditions

How to Choose This Part

• Suitable for high-voltage (400~500V) low-to-medium current applications
• Preferable when low gate charge and switching loss are important
• Not ideal for high-current designs due to relatively high R_DS(on)
• Compare with super-junction MOSFETs for higher efficiency designs

Typical Applications

• Switch Mode Power Supplies (SMPS)
• Power Factor Correction (PFC) circuits
• Electronic lamp ballasts (half-bridge topology)
• High-voltage DC-DC converters
• LED drivers and offline converters

Alternative / Equivalent Products

• IRFR420 (non-B version)
• STP5NK50Z (lower R_DS(on) alternative)
• FQPF5N50C (TO-220 package alternative)
• IPA50R series (Infineon super-junction upgrade option)

Other data sheets are available within the file: IRFR420, IRFU420B

IRFR420B Datasheet PDF Download