Vishay Siliconix IRFI634G

Overview

IRFI634G from Vishay Siliconix is a 250 V, 5.6 A N-channel power MOSFET in an isolated TO-220 FULLPAK package, featuring 0.45 Ω R_DS(on) at V_GS = 10 V, 41 nC total gate charge, and 2.5 kV_RMS isolation for high-voltage industrial switching applications including AC-DC PFC stages and motor drive half-bridges.

For engineers reviewing the IRFI634G datasheet, IRFI634G pinout, IRFI634G application, or IRFI634G equivalent, key selection criteria include its isolated package enabling direct heatsink mounting without mica washers, rugged 300 mJ single-pulse avalanche energy rating, and validated dV/dt immunity of 4.8 V/ns - critical for reliable operation in noisy inductive load environments.

Technical Context

This third-generation power MOSFET uses planar silicon technology optimized for fast switching and thermal robustness. Its isolated TO-220 FULLPAK construction integrates a high-dielectric molding compound that delivers 2.5 kV_RMS isolation and 4.8 mm sink-to-lead creepage distance - eliminating external insulation hardware in commercial-industrial designs.

The device supports unclamped inductive switching with repetitive avalanche current up to 5.6 A and features low internal source/drain inductance (L_S = 7.5 nH, L_D = 4.5 nH), enabling clean turn-on/turn-off waveforms under high dI/dt conditions (≤120 A/μs) when used with appropriate gate drive.

Key Specifications

Pinout & Package

IRFI634G is housed in a TO-220 FULLPAK package with integral isolation between the drain-connected tab and leads. The package provides 2.5 kV_RMS isolation and 4.8 mm creepage distance, enabling direct mechanical mounting to a heatsink without insulating hardware.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP20NM50FP and IXTP50N10P, the IRFI634G uniquely combines 250 V rating, integrated 2.5 kV isolation, and 300 mJ avalanche energy - making it the only drop-in solution for isolated high-voltage industrial switching where board space, thermal performance, and fault robustness are jointly constrained.

Availability

IRFI634G is available at Aetrix Electronics and suitable for industrial motor drives, AC-DC power factor correction, and uninterruptible power supplies requiring stable component supply across multi-year production cycles.

Supply support for IRFI634G 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 industrial, automotive, and computing applications.

The IRFI634G belongs to Vishay's third-generation high-voltage power MOSFET family, engineered specifically for ruggedized switching in commercial-industrial power conversion where isolation, thermal efficiency, and avalanche survivability are mandatory.

FAQ

What is the maximum continuous drain current for the IRFI634G at 100 °C case temperature?

The IRFI634G supports 3.5 A continuous drain current at T_C = 100 °C, as specified in its Absolute Maximum Ratings table. This derating reflects thermal limits of the TO-220 FULLPAK package and ensures junction temperature remains within the -55 to +150 °C operating range. At 25 °C case temperature, the rating increases to 5.6 A. Designers must verify heatsink sizing using the 3.6 °C/W R_thJC value to maintain safe operation under full load.

Does the IRFI634G require external insulation when mounted to a heatsink?

No, the IRFI634G does not require external insulation when mounted to a heatsink. Its TO-220 FULLPAK package incorporates a high-isolation molding compound providing 2.5 kV_RMS isolation and 4.8 mm creepage distance between the drain-connected tab and leads. This eliminates the need for mica washers or silicone pads in most commercial-industrial applications, simplifying assembly and improving thermal transfer efficiency compared to standard TO-220 variants.

What is the gate threshold voltage range for the IRFI634G, and how does it affect drive compatibility?

The IRFI634G has a gate-source threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V at T_J = 25 °C and I_D = 250 μA. This makes it compatible with both 5 V logic-level drivers and standard 10 V gate drivers. For full enhancement and minimal R_DS(on), a V_GS of 10 V is recommended. The relatively wide V_GS(th) range necessitates careful gate drive design to ensure consistent turn-on across temperature and unit-to-unit variation.

Can the IRFI634G be used in avalanche mode, and what are the limits?

Yes, the IRFI634G is rated for both single-pulse and repetitive avalanche operation. It supports 300 mJ single-pulse avalanche energy (E_AS) and 5.6 A repetitive avalanche current (I_AR) with 3.5 mJ repetitive energy (E_AR). These ratings assume proper gate biasing (V_GS ≥ 10 V), controlled dI/dt (<120 A/μs), and junction temperature below 150 °C. Repetitive avalanche operation must respect pulse width and duty cycle limits defined in Figure 11 of the datasheet to avoid cumulative thermal stress.

What is the typical reverse recovery time of the body diode in the IRFI634G?

The IRFI634G body diode exhibits a typical reverse recovery time (t_rr) of 220 ns at T_J = 25 °C, I_F = 5.6 A, and dI/dt = 100 A/μs, with a maximum of 440 ns. This fast recovery characteristic reduces switching losses in freewheeling and synchronous rectification applications. The corresponding reverse recovery charge (Q_rr) is 1.2–2.4 μC, which influences snubber design and EMI generation in high-frequency converters.