Vishay Siliconix IRF720

Overview

IRF720 from Vishay Siliconix is a 400 V, 3.3 A N-channel power MOSFET in TO-220AB package, featuring 1.8 Ω R_DS(on) at V_GS = 10 V, 20 nC total gate charge, and repetitive avalanche rating-designed for hard-switched flyback and snubberless AC-DC power supplies up to 50 W.

For engineers reviewing the IRF720 datasheet, IRF720 pinout, IRF720 application, or IRF720 equivalent, key selection criteria include its 400 V V_DS, 1.8 Ω on-resistance at 10 V drive, 2.5 °C/W junction-to-case thermal resistance, and validated unclamped inductive switching capability up to 190 mJ.

Technical Context

This third-generation planar VDMOS device uses ruggedized silicon design with dynamic dV/dt rating of 4.0 V/ns and body diode reverse recovery time (t_rr) of 270–600 ns at 100 A/μs. Its gate threshold voltage (2.0–4.0 V) and low Q_gd/Q_g ratio (11/20 = 55%) support stable hard-switching operation without spurious turn-on.

The IRF720 integrates a fast-recovery body diode rated for 3.3 A continuous source-drain current and 13 A pulsed current, with V_SD = 1.6 V at 3.3 A and T_J = 25 °C. Thermal performance is defined by R_thJC = 2.5 °C/W and R_thJA = 62 °C/W (max), enabling conduction-limited operation below 100 °C case temperature.

Key Specifications

Pinout & Package

TO-220AB package with isolated tab (drain-connected), standard 3-lead through-hole mounting, 6–32 or M3 screw torque specification (1.1 N·m), and 300 °C peak soldering temperature tolerance for 10 s.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP4NK50ZFP and FQP4N40, the IRF720 offers verified repetitive avalanche capability (I_AR = 3.3 A), lower R_DS(on), and an electrically isolated drain tab-making it uniquely suited for snubberless flyback and inductive load switching where reliability under transient overvoltage is critical.

Availability

IRF720 is available at Aetrix Electronics and suitable for AC-DC power supplies, motor control stages, and LED drivers requiring stable component supply with long-term industrial lifecycle support.

Supply support for IRF720 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 markets.

The IRF720 belongs to Vishay's third-generation power MOSFET family, engineered for cost-effective, ruggedized switching in commercial-industrial power conversion-emphasizing avalanche robustness, thermal efficiency, and ease of parallel operation.

FAQ

What is the maximum continuous drain current for IRF720 at 100 °C case temperature?

The IRF720 supports 2.1 A continuous drain current at T_C = 100 °C, per its linear derating factor of 0.40 W/°C from 50 W at 25 °C. This value is confirmed in the Absolute Maximum Ratings table and reflects thermal limitation-not silicon current density-and assumes proper heatsinking with R_thJC ≤ 2.5 °C/W. The IRF720 must not exceed this limit to maintain safe junction temperature below 150 °C.

Does IRF720 have a fully isolated drain tab in the TO-220AB package?

Yes, the IRF720 in TO-220AB package features an electrically isolated drain tab, meaning the metal tab is internally connected only to the drain terminal and not to the source or gate. This isolation allows direct mounting to a grounded heatsink without shorting the drain node, provided appropriate insulating hardware (e.g., mica washer + thermal grease) is used. The IRF720 datasheet explicitly confirms this configuration in the package outline and ordering information.

What is the body diode reverse recovery charge (Q_rr) of IRF720, and why does it matter?

The IRF720 has a body diode Q_rr of 1.4–3.0 μC, measured at T_J = 25 °C, I_F = 3.3 A, and dI/dt = 100 A/μs. This parameter directly impacts switching loss and EMI in hard-commutated topologies like flyback or buck-boost converters. Higher Q_rr increases turn-on loss in the complementary switch and can cause voltage overshoot; the IRF720's moderate Q_rr balances recovery speed and softness for reliable operation without external snubbers.

Can IRF720 be used as a direct replacement for IRF710 in existing designs?

No, the IRF720 is not a direct replacement for IRF710. While both are 400 V N-channel MOSFETs in TO-220AB, the IRF710 has R_DS(on) = 3.6 Ω and lower Q_g (14 nC), whereas the IRF720 offers 1.8 Ω and 20 nC. Substituting IRF720 may reduce conduction loss but increase gate drive demand and alter switching timing-requiring validation of gate driver capability, layout parasitics, and avalanche stress margins. The IRF720 datasheet does not claim pin compatibility or drop-in functionality with IRF710.

Is IRF720 suitable for logic-level gate drive applications?

No, the IRF720 is not a logic-level MOSFET. Its gate threshold voltage ranges from 2.0 V to 4.0 V, and it is specified for R_DS(on) at V_GS = 10 V-not 5 V. Driving the IRF720 with only 5 V will result in incomplete enhancement and excessive conduction loss. It requires a dedicated gate driver or controller capable of delivering ≥10 V to ensure full turn-on; using it with 3.3 V or 5 V microcontroller outputs without level-shifting is not recommended. The IRF720 datasheet confirms all key parameters are characterized at V_GS = 10 V.