Vishay Siliconix IRFR420

Overview

IRFR420 from Vishay Siliconix is a 500 V, 2.4 A N-channel surface-mount power MOSFET in DPAK (TO-252) package, featuring 3.0 Ω R_DS(on) at V_GS = 10 V, 19 nC total gate charge, and repetitive avalanche rating-designed for high-voltage DC-DC converters, offline SMPS, and motor control circuits requiring rugged switching.

For engineers reviewing the IRFR420 datasheet, IRFR420 pinout, IRFR420 application, or IRFR420 equivalent, this page delivers verified electrical specs, thermal derating data, body diode recovery characteristics, and real-world mounting guidance for PCB-level reliability in industrial power designs.

Technical Context

The IRFR420 employs third-generation planar vertical DMOS technology optimized for fast switching and avalanche robustness. Its 500 V V_DS rating supports operation across universal AC input ranges, while the 3.0 Ω on-resistance balances conduction loss and die size for cost-sensitive 1–2 W output stages.

Thermal design relies on its 3.0 °C/W junction-to-case resistance and 50 °C/W junction-to-ambient (PCB mount), enabling 2.5 W dissipation on a 1" FR-4 square. The 260–520 ns body diode reverse recovery time and 0.70–1.4 μC Q_rr define hard-switching behavior in flyback and forward topologies.

Key Specifications

Pinout & Package

DPAK (TO-252) surface-mount package with exposed drain pad for thermal conduction and mechanical anchoring. Standard 3-pin layout: Gate (G), Drain (D), Source (S); drain tab electrically connected to pin 2 (Drain).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel power MOSFET applications.

Compared with IRFR420, SiHFR420-GE3 offers identical performance in a fully compliant package, while IRFU420PbF trades surface-mount convenience for through-hole mechanical robustness and higher thermal resistance-making IRFR420 optimal for space-constrained, thermally managed SMT power stages.

Availability

IRFR420 is available at Aetrix Electronics and suitable for AC-DC power supplies, motor control interfaces, and lighting ballasts requiring stable component supply across long-lifecycle industrial programs.

Supply support for IRFR420 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Vishay Siliconix is a global leader in discrete semiconductors, specializing in high-reliability MOSFETs, diodes, and optoelectronics for power, signal, and sensing applications.

The IRFR420 belongs to Vishay's third-generation high-voltage power MOSFET family, engineered for ruggedness, fast switching, and cost-effective implementation in industrial and consumer power conversion systems.

FAQ

What is the maximum continuous drain current for IRFR420 at 100 °C case temperature?

The IRFR420 supports a continuous drain current of 1.5 A at T_C = 100 °C, as specified in the Absolute Maximum Ratings table. This value reflects thermal derating from the 2.4 A rating at 25 °C and is critical for heatsink-limited designs where junction temperature must remain below 150 °C. Designers should verify actual power dissipation using R_DS(on) and I_D² loss calculations alongside PCB copper area and ambient conditions to ensure safe operation of the IRFR420.

Does IRFR420 have a built-in body diode, and what are its key parameters?

Yes, the IRFR420 integrates a body diode inherent to its vertical N-channel MOSFET structure. Key parameters include a forward voltage of 1.6 V at I_S = 2.4 A and T_J = 25 °C, reverse recovery time of 260–520 ns, and reverse recovery charge of 0.70–1.4 μC. These values directly impact efficiency and EMI in hard-switched topologies like flyback converters, where the IRFR420 body diode conducts during the off-state before synchronous rectification or external diode takeover.

What is the gate threshold voltage range for IRFR420, and how does it affect drive requirements?

The IRFR420 has a gate-source threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V at I_D = 250 μA. This indicates it is a standard-level MOSFET requiring ≥10 V gate drive for full enhancement, not a logic-level device. Driving the IRFR420 with less than 8 V risks incomplete turn-on and excessive R_DS(on), increasing conduction loss. Proper gate drive design must ensure clean 10–15 V swing with adequate current capability to charge the 19 nC total gate charge within required switching times.

Can IRFR420 be used in avalanche mode, and what are the limits?

Yes, the IRFR420 is explicitly rated for repetitive avalanche operation with I_AR = 2.4 A and E_AR = 4.2 mJ per pulse, and single-pulse avalanche energy E_AS = 400 mJ. These ratings assume pulse width limited by junction temperature and proper PCB layout to minimize stray inductance. Operation in avalanche mode is intended for transient protection-not continuous duty-and requires verification of peak junction temperature using thermal impedance curves. The IRFR420's ruggedized design makes it suitable for such stress in well-designed clamp circuits.

What is the recommended PCB pad layout for IRFR420 in DPAK package?

Vishay Application Note AN826 specifies minimum recommended pads for the IRFR420's DPAK (TO-252) package: 0.224" × 0.180" (5.69 mm × 4.57 mm) for the source pad, 0.243" × 0.087" (6.18 mm × 2.20 mm) for the gate pad, and 0.420" × 0.055" (10.67 mm × 1.40 mm) for the drain thermal pad. A large copper pour connected to the drain tab improves thermal performance, and thermal vias under the pad enhance heat transfer to inner layers. Adhering to these dimensions ensures reliable solder joint integrity and thermal management for the IRFR420 in production assemblies.