Vishay Siliconix IRF744

Overview

IRF744 from Vishay Siliconix is a 450 V, 8.8 A N-channel power MOSFET in TO-220 package, optimized for high-voltage switching in offline SMPS and motor control. It features 0.63 Ω R_DS(on) at V_GS = 10 V, 80 nC total gate charge, and repetitive avalanche rating up to 8.8 A - enabling robust operation in clamped inductive loads such as flyback and forward converters.

For engineers reviewing the IRF744 datasheet, IRF744 pinout, IRF744 application, or IRF744 equivalent, key selection criteria include its 450 V V_DS, 125 W P_D at T_C = 25 °C, 1.0 °C/W R_thJC, fast 28 ns rise time, and body diode t_rr of 490–740 ns - all critical for high-efficiency, thermally constrained 100–500 kHz switch-mode designs.

Technical Context

This third-generation planar vertical MOSFET uses ruggedized silicon design with dynamic dV/dt rating (3.5 V/ns) and specified unclamped inductive switching capability. Its gate threshold voltage (2.0–4.0 V) and low Q_gd/Q_gs ratio (41/12 nC) support stable hard-switching and ease of paralleling without oscillation.

The device integrates a fast-recovery body diode (t_rr ≤ 740 ns, Q_rr ≤ 4.8 µC) and exhibits linear SOA behavior up to 150 °C junction temperature. Thermal resistance from junction-to-case is fixed at 1.0 °C/W, enabling predictable heatsink sizing for continuous 5.6 A operation at T_C = 100 °C.

Key Specifications

Pinout & Package

TO-220 package with isolated tab (drain-connected), standard 3-lead through-hole mounting. Tab is electrically connected to drain; mounting screw provides mechanical and thermal attachment to heatsink.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP4NK50ZFP and IXTP4N50D2, the IRF744 delivers higher current (8.8 A vs. 4 A) and proven repetitive avalanche capability - making it uniquely suitable for 30–60 W industrial flyback and motor drive stages where both voltage headroom and ruggedness are simultaneously required.

Availability

IRF744 is available at Aetrix Electronics and suitable for offline SMPS, AC motor drives, PFC pre-regulators, and inductive load switching modules requiring stable component supply and long-lifecycle support.

Supply support for IRF744 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 and passive components, specializing in high-reliability power MOSFETs, diodes, and optoelectronics for industrial, automotive, and computing markets.

The IRF744 belongs to Vishay's third-generation Power MOSFET family, engineered for cost-effective, rugged high-voltage switching in commercial-industrial power conversion - emphasizing avalanche robustness, thermal efficiency, and ease of system integration.

FAQ

What is the maximum continuous drain current for IRF744 at 100 °C case temperature?

The IRF744 supports 5.6 A continuous drain current at T_C = 100 °C, as specified in its Absolute Maximum Ratings table. This value accounts for thermal derating from the 8.8 A rating at 25 °C, using a linear derating factor of 1.0 W/°C and R_thJC = 1.0 °C/W. Designers must ensure heatsink design maintains case temperature ≤ 100 °C under worst-case load conditions to sustain this current reliably.

Does IRF744 have a built-in gate protection diode?

No, the IRF744 does not integrate a gate protection Zener diode. Its gate-source voltage rating is ±20 V, and gate leakage is specified at ±100 nA at ±20 V. External gate clamping (e.g., 15 V Zener) is recommended in noisy environments or when driving with high-impedance sources to prevent gate oxide damage. This differs from protected variants like STP4NK50ZFP, which include integrated gate Zener protection.

Can IRF744 replace IRF740 in an existing design?

Yes, the IRF744 can directly replace IRF740 in most designs due to identical TO-220 package, pinout, and voltage rating (both 400 V), but with improved performance: IRF744 offers lower R_DS(on) (0.63 Ω vs. 0.55 Ω for IRF740 is incorrect - actual IRF740 is 0.55 Ω; correction: IRF744's 0.63 Ω is slightly higher, but it adds 450 V rating and 540 mJ E_AS). Verify layout compatibility and re-evaluate gate drive strength due to higher Q_g (80 nC vs. IRF740's ~65 nC).

What is the body diode reverse recovery charge (Q_rr) of IRF744?

The IRF744 body diode has a reverse recovery charge Q_rr of 3.2–4.8 µC, measured at T_J = 25 °C, I_F = 8.8 A, and dI/dt = 100 A/µs. This parameter directly impacts switching loss during synchronous rectification or freewheeling phases. The relatively low Q_rr supports efficient operation in discontinuous conduction mode (DCM) flyback and boost converters without requiring complex snubbers.

Is IRF744 suitable for use in a half-bridge configuration?

Yes, the IRF744 is suitable for half-bridge configurations due to its 3.5 V/ns peak diode recovery dV/dt rating and dynamic dV/dt immunity - critical for preventing spurious turn-on during high dv/dt transitions across the high-side switch. However, gate drive isolation and careful layout to minimize common-source inductance are essential. Its 450 V rating supports 200–250 V DC bus applications with sufficient margin.