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

Vishay Siliconix IRF740A

Name: IRF740A
Brand: Vishay Siliconix
SKU: IRF740A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRF740A

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: TO-220-3

Datasheet:: IRF740A.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

IRF740A from Vishay Siliconix is a 400 V, 10 A N-channel power MOSFET in TO-220AB package, optimized for high-voltage switching in SMPS and UPS systems. It delivers R_DS(on) = 0.55 Ω at V_GS = 10 V, Q_g = 36 nC, and 630 mJ single-pulse avalanche energy - enabling robust, self-protected operation in flyback and forward converter topologies with US-line input.

For engineers reviewing the IRF740A datasheet, IRF740A pinout, IRF740A application, or IRF740A equivalent, key selection criteria include its 400 V V_DS, 125 W P_D at T_C = 25 °C, 1.0 °C/W R_thJC, and validated dV/dt ruggedness up to 5.9 V/ns - critical for reliable high-speed power switching in industrial and telecom power supplies.

Technical Context

The IRF740A employs planar vertical DMOS technology with fully characterized avalanche capability and dynamic dV/dt ruggedness. Its gate charge profile (Q_gs = 9.9 nC, Q_gd = 16 nC) supports predictable turn-on/turn-off timing in hard-switched topologies, while C_oss = 61 pF (effective, 0–320 V) enables stable snubber design.

Thermally, it features a low 1.0 °C/W junction-to-case resistance and operates across –55 °C to +150 °C. The integral body diode exhibits t_rr = 240–360 ns and Q_rr = 1.9–2.9 μC at I_F = 10 A, dI/dt = 100 A/μs - suitable for synchronous rectification and unclamped inductive switching.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	400 V - supports primary-side switching in 115/230 VAC-input SMPS with margin against line transients
R_DS(on)	0.55 Ω @ V_GS = 10 V - limits conduction loss to ≤ 33 W at 10 A DC, enabling thermally constrained designs
Q_g	36 nC - determines gate drive power and switching speed; compatible with standard 10–25 Ω gate resistors
E_AS	630 mJ - provides single-pulse avalanche immunity during overvoltage events without external clamping
R_thJC	1.0 °C/W - enables 125 W dissipation with ≤ 125 °C ΔT from case to junction under heatsinked conditions
t_r/t_f	35 ns / 22 ns - supports >500 kHz switching in resonant or quasi-resonant converters with controlled EMI
V_SD	2.0 V @ I_S = 10 A - defines forward drop of integrated body diode during freewheeling or synchronous rectification

Pinout & Package

IRF740A is housed in a through-hole TO-220AB package with isolated tab (drain-connected), rated for 125 W at T_C = 25 °C and mounting torque of 1.1 N·m (10 lbf·in).

Pin/Terminal	Circuit Role	Design Meaning
G (Gate)	Control terminal	Receives 10 V logic-level drive; threshold V_GS(th) = 2.0–4.0 V ensures reliable turn-on with standard PWM controllers
D (Drain)	High-side power output	Connected to internal die backside and metal tab; must be electrically isolated from heatsink unless referenced to system ground
S (Source)	Power return/reference node	Serves as common reference for gate drive and current sensing; ties to low-side switch source or ground in half-bridge configurations

Key Features

Feature	Design Value
Low gate charge (Q_g = 36 nC)	Reduces gate driver power demand and simplifies drive circuitry - no need for high-current buffer stages in 100–500 kHz SMPS
Improved avalanche ruggedness (E_AS = 630 mJ)	Eliminates need for external RCD clamp in flyback converters operating near maximum duty cycle or with leakage inductance spikes
Effective C_oss = 61 pF (0–320 V)	Enables accurate soft-switching timing prediction and reduces voltage overshoot during turn-off in resonant LLC topologies
Peak diode recovery dV/dt = 5.9 V/ns	Prevents false triggering in high-noise environments - critical for reliability in motor drives and industrial inverters
RoHS-compliant Pb-free variant (IRF740APbF-BE3)	Meets global environmental compliance without derating; halogen-free construction supports UL94 V-0 flammability requirements

Applications

Switch Mode Power Supply (SMPS)	Uninterruptible Power Supply (UPS)
Use Scenario: Primary-side switch in single-transistor flyback converter for 115 VAC input telecom adapters. IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer via transformer reset; operates at 65–130 kHz with fixed-frequency PWM. Use Value: 400 V V_DS and 630 mJ E_AS absorb reflected voltage spikes during demagnetization, eliminating need for TVS clamping.	Use Scenario: Inverter-stage switch in line-interactive UPS delivering 1 kVA output with battery backup. IC Role / Device Role / Timing Role: Low-loss power switch in half-bridge topology driving transformer-coupled output stage; handles bidirectional current during battery boost mode. Use Value: 10 A continuous drain current and 125 W P_D sustain 20 ms overload pulses without thermal shutdown, supporting surge ride-through.
High-Speed Power Switching	Industrial Motor Drive Stage
Use Scenario: Solid-state relay replacement in programmable logic controller (PLC) output modules switching 24–48 VDC loads. IC Role / Device Role / Timing Role: Fast-turning discrete switch replacing electromechanical relays; driven by microcontroller GPIO with optocoupler isolation. Use Value: 35 ns rise time and 22 ns fall time enable <100 ns total switching window - reducing transition losses and improving load response fidelity.	Use Scenario: Brake chopper switch in 3-phase AC motor drive dissipating regenerative energy into braking resistor. IC Role / Device Role / Timing Role: High-energy pulse switch activated during deceleration; subjected to repetitive 10 A avalanche current (I_AR = 10 A) and 12.5 mJ E_AR. Use Value: Validated repetitive avalanche rating allows direct integration without snubber networks - simplifying PCB layout and reducing BOM count.

Switch Mode Power Supply (SMPS)

Uninterruptible Power Supply (UPS)

Use Scenario: Primary-side switch in single-transistor flyback converter for 115 VAC input telecom adapters.

IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer via transformer reset; operates at 65–130 kHz with fixed-frequency PWM.

Use Value: 400 V V_DS and 630 mJ E_AS absorb reflected voltage spikes during demagnetization, eliminating need for TVS clamping.

Use Scenario: Inverter-stage switch in line-interactive UPS delivering 1 kVA output with battery backup.

IC Role / Device Role / Timing Role: Low-loss power switch in half-bridge topology driving transformer-coupled output stage; handles bidirectional current during battery boost mode.

Use Value: 10 A continuous drain current and 125 W P_D sustain 20 ms overload pulses without thermal shutdown, supporting surge ride-through.

High-Speed Power Switching

Industrial Motor Drive Stage

Use Scenario: Solid-state relay replacement in programmable logic controller (PLC) output modules switching 24–48 VDC loads.

IC Role / Device Role / Timing Role: Fast-turning discrete switch replacing electromechanical relays; driven by microcontroller GPIO with optocoupler isolation.

Use Value: 35 ns rise time and 22 ns fall time enable <100 ns total switching window - reducing transition losses and improving load response fidelity.

Use Scenario: Brake chopper switch in 3-phase AC motor drive dissipating regenerative energy into braking resistor.

IC Role / Device Role / Timing Role: High-energy pulse switch activated during deceleration; subjected to repetitive 10 A avalanche current (I_AR = 10 A) and 12.5 mJ E_AR.

Use Value: Validated repetitive avalanche rating allows direct integration without snubber networks - simplifying PCB layout and reducing BOM count.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP4NK50ZFP	500 V V_DS, R_DS(on) = 1.4 Ω @ 10 V, Q_g = 11 nC - higher voltage rating but higher on-resistance and lower current capability (4 A)	Better suited for 230 VAC universal-input SMPS requiring extra voltage margin; less optimal for high-current 115 VAC designs	Select when voltage headroom >100 V is required and peak current ≤ 4 A; not recommended for IRF740A's 10 A continuous use case.
IXTP10N50D2	500 V V_DS, R_DS(on) = 0.65 Ω @ 10 V, Q_g = 22 nC - lower gate charge but higher R_DS(on) and same 10 A rating	Superior switching efficiency in high-frequency (>300 kHz) converters due to reduced Q_g, but higher conduction loss at full load	Prefer for resonant topologies where switching loss dominates; retain IRF740A when conduction loss or avalanche robustness is primary concern.

Compared with STP4NK50ZFP and IXTP10N50D2, the IRF740A offers the best balance of 400 V rating, 0.55 Ω R_DS(on), and 630 mJ avalanche energy - making it uniquely suited for cost-sensitive, high-reliability 115 VAC SMPS and UPS primary switches where both conduction and transient robustness matter.

Availability

IRF740A is available at Aetrix Electronics and suitable for switch mode power supply (SMPS), uninterruptible power supply (UPS), and high-speed power switching applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for IRF740A 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 power, signal, and sensing applications.

The IRF740A belongs to Vishay's legacy high-voltage power MOSFET family designed specifically for ruggedized, high-efficiency switching in industrial and telecom power conversion - emphasizing avalanche survivability, thermal stability, and manufacturability in TO-220 platforms.

FAQ

What is the maximum continuous drain current for the IRF740A at 100 °C case temperature?

The IRF740A supports 6.3 A continuous drain current at T_C = 100 °C, as specified in its Absolute Maximum Ratings table. This derating from 10 A at 25 °C reflects thermal limitations of the TO-220AB package and ensures safe operation within its 1.0 °C/W R_thJC and 150 °C maximum junction temperature. Designers must verify heatsink performance to maintain T_C ≤ 100 °C under full-load conditions.

Does the IRF740A have a built-in body diode, and what are its key parameters?

Yes, the IRF740A integrates a fast-recovery body diode with V_SD = 2.0 V at I_S = 10 A and T_J = 25 °C, reverse recovery time t_rr = 240–360 ns, and Q_rr = 1.9–2.9 μC. These values are measured at I_F = 10 A and dI/dt = 100 A/μs, making the diode suitable for freewheeling in flyback converters and limited synchronous rectification - though external Schottky diodes are preferred for high-efficiency secondary-side rectification.

Is the IRF740A suitable for logic-level gate drive?

No, the IRF740A is not a logic-level MOSFET. Its gate threshold voltage V_GS(th) ranges from 2.0 V to 4.0 V, but it requires V_GS = 10 V to achieve R_DS(on) = 0.55 Ω. Driving it with 3.3 V or 5 V logic signals results in incomplete turn-on and excessive conduction loss. A dedicated gate driver or level-shifting circuit supplying ≥10 V is mandatory for full performance and thermal safety in the IRF740A.

What is the avalanche energy rating of the IRF740A, and how is it tested?

The IRF740A is rated for 630 mJ single-pulse avalanche energy (E_AS) under test conditions of V_DD = 50 V, starting T_J = 25 °C, L = 12.6 mH, R_g = 25 Ω, and I_AS = 10 A. This rating is verified per JEDEC JESD24-11 and confirms the device can safely absorb inductive energy without failure - critical for flyback transformer reset and unclamped inductive switching in SMPS and UPS designs.

How does the IRF740A's effective output capacitance (C_oss) impact snubber design?

The IRF740A specifies an effective C_oss of 61 pF across 0–320 V, which directly determines the energy stored in the drain-source capacitance during turn-off (E = ½C_ossV²). This value enables precise calculation of snubber resistor and capacitor values to limit voltage overshoot and damp ringing - especially important in flyback and forward converters where leakage inductance couples with C_oss to generate voltage spikes exceeding V_DS rating.

IRF740A Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

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 @ 6A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 36 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 1030 pF @ 25 V

FET Feature:: -

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

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220AB

IRF740A FAQ

1.How can I place an order for IRF740A through Aetrix?

Please submit a Request for Quotation (RFQ) for IRF740A 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 IRF740A reliable?

The price and inventory of IRF740A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRF740A is usually 5 days.

3.What payment methods are accepted for IRF740A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRF740A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRF740A?

IRF740A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRF740A 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 IRF740A?

For technical support, including IRF740A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRF740A requirements.

6.How does Aetrix verify that IRF740A is sourced from the original manufacturer or authorized distributors?

All IRF740A 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 IRF740A meets industry standards.

7.What is the process for return or replacement of IRF740A?

All IRF740A units undergo pre-shipment inspection (PSI). If there is an issue with IRF740A, 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 IRF740A part is unused and in its original packaging.

Return procedure for IRF740A:

1.Submit a request within 90 days.

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

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