IRF740 Pinout, Equivalent, Application, Datasheet

The IRF740 is a high-voltage N-Channel MOSFET widely used in SMPS, inverter circuits, high-voltage LED drivers, and industrial power supplies. Its strong switching performance, durable TO-220 package, and high breakdown voltage make it a preferred choice for efficient high-voltage power conversion. Before going deeper, here is the essential IRF740 pinout to ensure safe and correct circuit integration.

Introduction to IRF740 N-Channel MOSFET

The IRF740 is a 400-volt N-Channel MOSFET designed for high-voltage, medium-current power applications. It is widely used in offline SMPS, high-voltage converters, motor control drivers, and inverter circuits. With a 10A continuous drain current and fast switching behavior, the IRF740 delivers efficient operation in applications requiring stable high-voltage switching.

IRF740 N-Channel MOSFET

Pinout of IRF740

Pin Configuration of IRF740 Pinout

The IRF740 uses the standard TO-220 G-D-S pin configuration. The Gate receives the control voltage, the Drain connects to the load or transformer winding, and the Source connects to the system ground. Proper pin identification is essential in high-voltage circuits to maintain safety and prevent breakdown during switching events.

Key Features of IRF740 MOSFET

• High-voltage N-Channel MOSFET for demanding applications
• Fast switching capability suitable for SMPS and inverter circuits
• Rugged construction with high avalanche energy rating
• Low gate charge for medium-high frequency switching
• Handles significant power dissipation in TO-220 package
• Reliable performance across wide temperature ranges
• Suitable for high-voltage LED drivers and DC-DC converters

Datasheet and Specifications of IRF740 MOSFET

• Drain–Source Voltage (VDS): 400V
• Gate–Source Voltage (VGS): ±20V
• Continuous Drain Current (ID): 10A
• Pulsed Drain Current (IDM): 40A
• Total Power Dissipation (Ptot): 125W
• On-Resistance (RDS(on)): 0.55Ω
• Storage Temperature (Tstg): –65°C to +150°C
• Junction Temperature (TJ): 150°C
• Package: TO-220
• Pin Configuration: Gate–Drain–Source (G-D-S)

Working Principle of IRF740 MOSFET

The IRF740 operates as a voltage-controlled switch. When adequate positive voltage is applied to the gate, a conductive channel forms, allowing current to flow from drain to source. Its high breakdown voltage makes it suitable for circuits that involve rectified mains, flyback transformer primaries, and high-voltage switching stages. Fast switching minimizes heat losses, improving overall conversion efficiency.

More Circuit Layouts

Applications of IRF740 MOSFET

• SMPS primary switching
• High-voltage DC-DC converters
• LED drivers and lighting ballasts
• Inverter circuits
• High-voltage power supplies
• Motor driver circuits
• Flyback and forward converters
• Industrial power control modules

Equivalent and Alternative MOSFETs

Possible replacements or equivalents include:

Direct or close equivalents:

• IRF730
• IRF740A
• IRF720 (lower current)

Possible alternatives (verify before use):

• 2SK1118
• BUZ90A
• STF10N50
• IRF840 (higher voltage)

Always compare voltage, current, and RDS(on) before substituting.

Frequently Asked Questions (FAQ)

Q1: Can IRF740 be used in SMPS circuits?
Yes, it is one of the most commonly used MOSFETs in flyback and forward SMPS designs.

Q2: Does IRF740 require a heatsink?
Yes, especially when switching high current or operating near its power limit.

Q3: Can IRF740 replace IRF720?
Yes, provided the circuit can handle its higher current capability and similar voltage ratings.

Q4: Is IRF740 suitable for high-frequency operation?
It works well at medium switching frequencies typical for SMPS designs.

Conclusion

The IRF740 N-Channel MOSFET is a reliable, efficient, and widely used high-voltage switching device. Its strong power-handling ability, fast switching response, and durable TO-220 package make it ideal for SMPS, LED drivers, high-voltage regulators, and inverter circuits. For designers seeking a cost-effective and robust MOSFET for high-voltage applications, the IRF740 remains a dependable choice.

Datasheet & Pinout of IRF740 N-Channel MOSFET

Click the following Button to download the datasheet of IRF740 MOSFET :

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