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

Vishay Siliconix IRF740AS

Name: IRF740AS
Brand: Vishay Siliconix
SKU: IRF740AS
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRF740AS

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: TO-263-3, D2PAK (2 Leads + Tab), TO-263AB

Datasheet:: IRF740AS.pdf

Description:: MOSFET N-CH 400V 10A D2PAK

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Product details

Overview

IRF740AS from Vishay Siliconix is a 400 V, 10 A N-channel power MOSFET in D2PAK (TO-263) package, featuring R_DS(on) = 0.55 Ω at V_GS = 10 V, Q_g = 36 nC, and 630 mJ single-pulse avalanche energy - optimized for high-voltage switch-mode power supply (SMPS) primary-side switching in flyback and forward topologies.

For engineers reviewing the IRF740AS datasheet, IRF740AS pinout, IRF740AS application, or IRF740AS equivalent, this device serves as a rugged, RoHS-compliant high-voltage switching transistor with characterized dV/dt immunity (5.9 V/ns), fully specified C_{oss eff.} (61 pF), and validated unclamped inductive switching performance under 10 A avalanche current conditions.

Technical Context

The IRF740AS employs a planar high-voltage silicon process with optimized gate oxide and cell layout to achieve stable threshold voltage (2.0–4.0 V) and low gate charge (36 nC), enabling efficient drive with standard gate drivers. Its dynamic parameters - including C_iss = 1030 pF, C_oss = 170 pF (at V_DS = 25 V), and C_rss = 7.7 pF - support predictable hard-switching behavior in 100–200 kHz SMPS designs.

Thermal design is enabled by R_thJC = 1.0 °C/W and rated continuous power dissipation of 125 W at T_C = 25 °C, with linear derating to 6.3 A at 100 °C case temperature. The integral body diode exhibits t_rr = 240–360 ns and Q_rr = 1.9–2.9 μC, supporting moderate-frequency freewheeling in non-synchronous converters.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	400 V - supports 320 V DC bus operation with 25 % margin for line surges and ringing in offline SMPS.
R_DS(on)	0.55 Ω @ V_GS = 10 V - enables <1.5 W conduction loss at 6 A RMS in primary-side switching applications.
Q_g	36 nC - determines gate driver current requirement (~3.6 mA avg. at 100 kHz, 10 V swing) and switching speed control.
E_AS	630 mJ - validates robustness against unclamped inductive turn-off events without external snubbers.
t_r/t_f	35 ns / 22 ns - defines minimum practical switching period and EMI generation profile in hard-switched topologies.
C_{oss eff.}	61 pF - represents effective output capacitance during V_DS rise from 0 to 320 V, critical for ZVS transition analysis.
I_D (T_C = 100 °C)	6.3 A - sets maximum sustainable current in thermally constrained PCB layouts with limited heatsinking.

Pinout & Package

D2PAK (TO-263) surface-mount package with exposed drain pad for thermal and electrical connection; 3-pin configuration (G, D, S) with drain tab electrically tied to pin 2 (D) and thermally connected to PCB copper area.

Pin/Terminal	Circuit Role	Design Meaning
G (Gate)	Control terminal	Receives 10 V logic-level drive; requires <36 nC charge to fully enhance; sensitive to ESD (±30 V rating).
D (Drain)	High-voltage power input	Connected to primary winding and DC bus; carries full switching current and avalanche energy; ties to thermal pad.
S (Source)	Power return and reference	Common node for gate drive return and current sensing; referenced to controller ground in non-isolated configurations.

Key Features

Feature	Design Value
Low Q_g (36 nC)	Reduces gate driver power loss and simplifies drive circuitry - no need for high-current buffer stages in 100–200 kHz SMPS.
Characterized C_{oss eff.} (61 pF)	Enables accurate dead-time and soft-switching design in resonant converters without iterative measurement.
Avalanche-rated (E_AS = 630 mJ)	Eliminates need for external clamping circuits in flyback transformer reset and inductive load switching.
Improved dV/dt ruggedness (5.9 V/ns)	Prevents false turn-on during high dv/dt transients in high-side configurations without extra gate resistors.
Fully specified body diode (t_rr, Q_rr)	Supports reliable freewheeling analysis in non-synchronous rectification, avoiding unexpected voltage spikes.

Applications

Offline Flyback SMPS	UPS Inverter Stage
Use Scenario: Primary-side switch in universal-input (85–265 VAC) flyback converter delivering 24–48 V output at up to 100 W. IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer via transformer primary; operates at 65–100 kHz with duty cycle modulation. Use Value: 400 V rating accommodates 375 V peak DC bus plus 25 % safety margin; 630 mJ E_AS handles transformer leakage inductance spikes without snubber.	Use Scenario: DC-AC inverter bridge leg in line-interactive UPS handling 500–1000 VA loads with battery backup. IC Role / Device Role / Timing Role: High-side switching element in half-bridge topology; commutated at 20–50 kHz with PWM-controlled output waveform. Use Value: R_DS(on) = 0.55 Ω limits conduction loss to <3.5 W at 8 A RMS; 125 W P_D rating supports short-term overload capability during battery discharge.
Forward Converter Primary Switch	Industrial HV DC-DC Isolator
Use Scenario: Main switch in single-transistor forward converter for telecom 48 V distribution systems with active clamp reset. IC Role / Device Role / Timing Role: Sustains 400 V blocking while conducting 10 A peak primary current; switched at 200–500 kHz with precise timing control. Use Value: Low Q_gd/Q_gs ratio (16/9.9) improves Miller immunity during high dV/dt transitions; validated 10 A I_AR ensures safe reset operation.	Use Scenario: Isolated DC-DC stage in industrial PLC power module converting 380 V DC input to 24 V isolated output. IC Role / Device Role / Timing Role: Primary-side switching transistor in phase-shifted full-bridge topology operating at 100–150 kHz. Use Value: C_iss = 1030 pF and C_oss = 170 pF enable predictable zero-voltage switching timing; R_thJC = 1.0 °C/W allows direct mounting to aluminum chassis for passive cooling.

Offline Flyback SMPS

UPS Inverter Stage

Use Scenario: Primary-side switch in universal-input (85–265 VAC) flyback converter delivering 24–48 V output at up to 100 W.

IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer via transformer primary; operates at 65–100 kHz with duty cycle modulation.

Use Value: 400 V rating accommodates 375 V peak DC bus plus 25 % safety margin; 630 mJ E_AS handles transformer leakage inductance spikes without snubber.

Use Scenario: DC-AC inverter bridge leg in line-interactive UPS handling 500–1000 VA loads with battery backup.

IC Role / Device Role / Timing Role: High-side switching element in half-bridge topology; commutated at 20–50 kHz with PWM-controlled output waveform.

Use Value: R_DS(on) = 0.55 Ω limits conduction loss to <3.5 W at 8 A RMS; 125 W P_D rating supports short-term overload capability during battery discharge.

Forward Converter Primary Switch

Industrial HV DC-DC Isolator

Use Scenario: Main switch in single-transistor forward converter for telecom 48 V distribution systems with active clamp reset.

IC Role / Device Role / Timing Role: Sustains 400 V blocking while conducting 10 A peak primary current; switched at 200–500 kHz with precise timing control.

Use Value: Low Q_gd/Q_gs ratio (16/9.9) improves Miller immunity during high dV/dt transitions; validated 10 A I_AR ensures safe reset operation.

Use Scenario: Isolated DC-DC stage in industrial PLC power module converting 380 V DC input to 24 V isolated output.

IC Role / Device Role / Timing Role: Primary-side switching transistor in phase-shifted full-bridge topology operating at 100–150 kHz.

Use Value: C_iss = 1030 pF and C_oss = 170 pF enable predictable zero-voltage switching timing; R_thJC = 1.0 °C/W allows direct mounting to aluminum chassis for passive cooling.

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
STP4NK40ZFP	400 V, 3.5 A, R_DS(on) = 1.4 Ω, Q_g = 12 nC, TO-220FP package	Lower current rating and higher R_DS(on); suited for <50 W designs with space-constrained through-hole mounting.	Select when lower gate charge and compact footprint outweigh need for 10 A current handling.
IXTH10N40L2	400 V, 10 A, R_DS(on) = 0.45 Ω, Q_g = 42 nC, TO-247 package	Lower on-resistance but higher Q_g and larger through-hole package; better thermal performance at >100 °C case temp.	Choose for higher-efficiency requirements where board space permits TO-247 and gate drive can support 42 nC.

Compared with STP4NK40ZFP and IXTH10N40L2, the IRF740AS delivers balanced trade-offs: sufficient 10 A current capability with surface-mount D2PAK packaging, moderate Q_g for ease of drive, and proven avalanche robustness - making it optimal for mid-power SMPS where thermal management and layout density are co-constrained.

Availability

IRF740AS 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 assurance, and traceable RoHS-compliant sourcing.

Supply support for IRF740AS 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 power MOSFETs, diodes, and optoelectronics with emphasis on ruggedness, precision, and manufacturability.

The IRF740AS belongs to Vishay's high-voltage planar MOSFET product line, engineered for primary-side switching in offline AC-DC converters where avalanche capability, dV/dt immunity, and consistent parametric stability across temperature are critical.

FAQ

What is the maximum continuous drain current for IRF740AS at 100 °C case temperature?

The IRF740AS supports 6.3 A continuous drain current at T_C = 100 °C, as specified in the Absolute Maximum Ratings table. This value reflects thermal derating from its 10 A rating at 25 °C and must be verified against actual PCB copper area, heatsinking, and ambient airflow in the target application. The IRF740AS datasheet provides derating curves (Fig. 8) to confirm safe operation under real thermal conditions.

Does IRF740AS have a built-in body diode, and what are its key recovery characteristics?

Yes, the IRF740AS integrates a parasitic body diode inherent to its vertical N-channel MOSFET structure. Its reverse recovery time (t_rr) is 240–360 ns and reverse recovery charge (Q_rr) is 1.9–2.9 μC at T_J = 25 °C, IF = 10 A, and dI/dt = 100 A/μs. These values are fully characterized and documented in the IRF740AS datasheet, enabling accurate loss estimation in non-synchronous topologies.

Is IRF740AS RoHS-compliant and halogen-free?

Yes, the IRF740AS is offered in lead (Pb)-free and halogen-free versions, as confirmed in the Ordering Information section of the Vishay datasheet (S21-0901-Rev. D). The part number IRF740ASTRRPbFa explicitly denotes Pb-free and halogen-free construction per Vishay's material categorization standard (doc?99912). Compliance documentation is available upon request from Aetrix Electronics.

What is the gate-source threshold voltage range for IRF740AS, and how does it affect drive requirements?

The IRF740AS has a gate-source threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V at T_J = 25 °C and I_D = 250 μA. This means full enhancement requires ≥10 V gate drive to ensure R_DS(on) remains at 0.55 Ω; operation below 6 V risks incomplete turn-on and excessive conduction loss. The IRF740AS is not a logic-level device and must be driven with a dedicated gate driver or level-shifted controller output.

Can IRF740AS replace IRF740AL in existing designs?

The IRF740AS and IRF740AL share identical electrical specifications and thermal ratings but differ in package: IRF740AS uses D2PAK (TO-263), while IRF740AL uses I2PAK (TO-262). Mechanical compatibility depends on PCB footprint - the D2PAK variant has a smaller outline and different lead pitch. The IRF740AS cannot be used as a drop-in replacement without verifying land pattern, thermal pad layout, and solder reflow profile alignment with the D2PAK mechanical drawing (doc?91364).

IRF740AS Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

Package/Case:: TO-263-3, D2PAK (2 Leads + Tab), TO-263AB

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):: 3.1W (Ta), 125W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: TO-263 (D2PAK)

IRF740AS FAQ

1.How can I place an order for IRF740AS through Aetrix?

Please submit a Request for Quotation (RFQ) for IRF740AS 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 IRF740AS reliable?

The price and inventory of IRF740AS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRF740AS is usually 5 days.

3.What payment methods are accepted for IRF740AS?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRF740AS transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRF740AS?

IRF740AS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRF740AS 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 IRF740AS?

For technical support, including IRF740AS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRF740AS requirements.

6.How does Aetrix verify that IRF740AS is sourced from the original manufacturer or authorized distributors?

All IRF740AS 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 IRF740AS meets industry standards.

7.What is the process for return or replacement of IRF740AS?

All IRF740AS units undergo pre-shipment inspection (PSI). If there is an issue with IRF740AS, 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 IRF740AS part is unused and in its original packaging.

Return procedure for IRF740AS:

1.Submit a request within 90 days.

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

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