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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > FETs, MOSFETs

STMicroelectronics IRF740

Name: IRF740
Brand: STMicroelectronics
SKU: IRF740
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRF740

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-220-3

Datasheet:: IRF740.pdf

Description:: MOSFET N-CH 400V 10A TO220AB

Quantity:: RFQ Add To RFQ list

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Product details

Overview

IRF740 from STMicroelectronics is an N-channel enhancement-mode PowerMESH™ II MOSFET rated for 400 V drain-source voltage, 0.46 Ω typical R_DS(on) at V_GS = 10 V and I_D = 5.3 A, and 10 A continuous drain current at T_C = 25°C. It serves as a high-voltage switching device in offline SMPS, motor drives, and DC-DC converters where ruggedness and fast switching are required.

For engineers reviewing the IRF740 datasheet, IRF740 pinout, IRF740 application, or IRF740 equivalent, key selection criteria include its 400 V V_DS, 125 W P_tot at T_C = 25°C, 1.0 W/°C derating factor, 4.0 V/ns dv/dt capability, and 100% avalanche tested construction - all critical for reliable high-voltage power switching design.

Technical Context

The IRF740 employs ST's PowerMESH™ II layout, which improves R_DS(on) × area while maintaining low gate charge (35 nC total) and minimal intrinsic capacitances (C_iss = 1400 pF, C_oss = 220 pF). Its gate threshold voltage (2–4 V) enables standard 10 V gate drive compatibility.

It features a built-in source-drain diode with 10 A continuous forward current, 1.6 V forward voltage at I_SD = 10 A, and 370 ns reverse recovery time under specified inductive switching conditions - supporting synchronous rectification and freewheeling roles in hard-switched topologies.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	400 V - supports primary-side switching in universal-input AC-DC supplies up to 265 VAC.
R_DS(on)	0.46 Ω (typ) - limits conduction loss to ≤2.3 W at 10 A DC, enabling thermally manageable operation with modest heatsinking.
I_D (cont)	10 A @ T_C = 25°C - defines maximum steady-state current before thermal derating applies.
Q_g	35 nC - determines gate driver power requirement and influences switching speed in hard-switched circuits.
dv/dt	4.0 V/ns - ensures immunity to parasitic turn-on during high-slew-rate voltage transients in bridge configurations.
E_AS	520 mJ - quantifies unclamped inductive switching robustness; allows safe operation without external snubbers in many flyback or buck-derived topologies.
R_thj-case	1.0 °C/W - enables direct junction-to-heatsink thermal path modeling for thermal design of TO-220 mounted units.

Pinout & Package

IRF740 is housed in a through-hole TO-220 package with three leads: Drain (tab), Gate, and Source. The metal tab is electrically connected to the Drain terminal and must be insulated from heatsink unless circuit topology permits common-drain configuration.

Pin/Terminal	Circuit Role	Design Meaning
1 (Lead)	Gate	Controls channel conduction; requires ≥10 V drive for full enhancement; sensitive to ESD.
2 (Lead)	Drain	High-voltage output node; electrically tied to metal tab; must be isolated from heatsink unless referenced to same potential.
3 (Lead)	Source	Return path for load current; reference for gate drive; forms common node with body diode cathode.

Key Features

Feature	Design Value
100% avalanche tested	Guarantees single-pulse energy handling up to 520 mJ without failure - eliminates need for overvoltage clamping in many inductive load designs.
Low gate charge (35 nC)	Reduces gate driver power dissipation and enables higher PWM frequencies without excessive driver heating.
Exceptional dv/dt capability (4.0 V/ns)	Prevents false triggering during rapid voltage transitions in half-bridge or LLC resonant converter primary switches.
Very low C_oss (220 pF)	Minimizes turn-off losses and improves zero-voltage switching (ZVS) margin in resonant topologies.

Applications

Offline AC-DC SMPS

Industrial Motor Drives

Use Scenario: Primary-side switch in 50–200 W flyback or forward converters operating from 85–265 VAC input.

IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer into transformer primary winding on each PWM cycle.

Use Value: 400 V rating accommodates reflected output voltage plus leakage spike; 100% avalanche testing avoids snubber complexity.

Use Scenario: Half-bridge high-side switch driving brushed DC motors or small BLDC inverters in HVAC blowers or pumps.

IC Role / Device Role / Timing Role: Fast-turning power switch delivering pulsed DC to motor windings under microcontroller PWM control.

Use Value: Low R_DS(on) reduces I²R loss at 5–10 A loads; 370 ns diode t_rr supports efficient freewheeling during dead-time intervals.

DC-DC Boost Converters

Inductive Load Switching

Use Scenario: Step-up stage in solar microinverters or battery-powered industrial equipment requiring >300 V output.

IC Role / Device Role / Timing Role: Main switching element in boost topology, sustaining high output voltage while conducting high peak currents.

Use Value: 400 V V_DS provides safety margin above 350 V nominal output; 125 W P_tot supports transient overload handling.

Use Scenario: Solenoid, relay, or transformer primary driver in PLC I/O modules or industrial automation controllers.

IC Role / Device Role / Timing Role: Robust unidirectional switch managing inductive energy storage and release cycles.

Use Value: 520 mJ E_AS withstands repeated unclamped inductive turn-off without degradation; TO-220 mechanical stability suits board-level mounting.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP7NK40Z	400 V, 7 A, R_DS(on) = 0.55 Ω, Zener-protected gate, lower Q_g (24 nC)	Lower current rating; better suited for <8 A average loads with tighter gate drive constraints	Select when gate drive capability is limited and avalanche robustness remains critical.
FQP4N40	400 V, 4 A, R_DS(on) = 1.6 Ω, TO-220, no avalanche rating specified	Lower current and higher on-resistance; not rated for repetitive avalanche stress	Acceptable only in non-critical, low-duty-cycle, or well-clamped inductive applications.

Compared with STP7NK40Z and FQP4N40, the IRF740 offers superior current handling (10 A vs. 7 A/4 A) and verified avalanche ruggedness (520 mJ), making it preferred for sustained high-power switching where thermal and transient reliability are prioritized over minimal gate charge.

Availability

IRF740 is available at Aetrix Electronics and suitable for offline AC-DC SMPS, industrial motor drives, and DC-DC boost converters requiring stable component supply and long-term industrial lifecycle support.

Supply support for IRF740 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The IRF740 belongs to ST's PowerMESH™ II high-voltage MOSFET product line, engineered specifically for rugged, high-efficiency switching in offline power conversion and industrial control systems.

FAQ

Is IRF740 suitable for use in a half-bridge configuration?

Yes - its 4.0 V/ns dv/dt capability and 100% avalanche testing make it suitable for half-bridge topologies. However, proper gate drive isolation, shoot-through prevention, and adequate dead-time control are essential. The metal tab (Drain) must be electrically isolated from the heatsink unless both switches share the same drain reference.

What is the maximum allowable case temperature for continuous operation?

The IRF740 supports 10 A continuous drain current only at T_C = 25°C. At T_C = 100°C, the rated continuous current drops to 6.3 A due to thermal derating. Operation beyond 150°C junction temperature violates absolute maximum ratings and risks permanent failure.

Does IRF740 have integrated gate protection?

No - the IRF740 lacks integrated gate Zener protection. External gate resistors (typically 10–47 Ω) and TVS diodes (e.g., 15 V) are recommended to suppress ESD and voltage overshoot, especially in high-noise industrial environments or when driving inductive loads.

Can IRF740 replace IRF740B in existing designs?

No - IRF740B is a different part (Infineon, obsolete) with distinct R_DS(on) (0.55 Ω), gate charge (60 nC), and packaging (TO-220AB). While both are 400 V N-channel MOSFETs, electrical and thermal behavior differ significantly; redesign validation is required before substitution.

IRF740 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: PowerMESH™ II

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 400 V

Current - Continuous Drain (Id) @ 25°C:: 10A (Tc)

Drive Voltage (Max Rds On, Min Rds On):: 10V

Rds On (Max) @ Id, Vgs:: 550mOhm @ 5.3A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 43 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 1400 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 125W (Tc)

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

IRF740 FAQ

1.How can I place an order for IRF740 through Aetrix?

Please submit a Request for Quotation (RFQ) for IRF740 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for IRF740 reliable?

The price and inventory of IRF740 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRF740 is usually 5 days.

3.What payment methods are accepted for IRF740?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRF740 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRF740?

IRF740 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRF740 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for IRF740?

For technical support, including IRF740 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRF740 requirements.

6.How does Aetrix verify that IRF740 is sourced from the original manufacturer or authorized distributors?

All IRF740 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that IRF740 meets industry standards.

7.What is the process for return or replacement of IRF740?

All IRF740 units undergo pre-shipment inspection (PSI). If there is an issue with IRF740, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The IRF740 part is unused and in its original packaging.

Return procedure for IRF740:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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