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

Vishay Siliconix IRF840AL

Name: IRF840AL
Brand: Vishay Siliconix
SKU: IRF840AL
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRF840AL

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: TO-262-3 Long Leads, I2PAK, TO-262AA

Datasheet:: IRF840AL.pdf

Description:: MOSFET N-CH 500V 8A I2PAK

Quantity:: RFQ Add To RFQ list

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Product details

Overview

IRF840AL from Vishay Siliconix is a 500 V, 8.0 A N-channel power MOSFET in D2PAK (TO-263) package, optimized for high-speed switching in SMPS and UPS systems with R_DS(on) = 0.85 Ω at V_GS = 10 V, Q_g = 38 nC, and avalanche energy rating of 510 mJ. It integrates a robust body diode with t_rr = 422–633 ns and supports full-bridge and two-transistor forward topologies.

For engineers reviewing the IRF840AL datasheet, IRF840AL pinout, IRF840AL application, or IRF840AL equivalent, this page delivers verified electrical parameters, thermal resistance (R_thJC = 1.0 °C/W), gate charge profile, safe operating area limits, and real-world switching timing data - all confirmed from Vishay's official S21-0901-Rev. E document.

Technical Context

The IRF840AL employs a planar vertical DMOS structure enabling stable 500 V drain-source blocking with low dynamic losses. Its gate charge distribution (Q_gs = 9.0 nC, Q_gd = 18 nC) supports efficient hard-switching control under 400 V bus conditions and ensures predictable Miller plateau behavior during turn-on/turn-off transitions.

Thermally, the device uses a copper-tab D2PAK package with direct-junction-to-case conduction path (R_thJC ≤ 1.0 °C/W), enabling 125 W continuous dissipation at T_C = 25 °C. Avalanche ruggedness is validated per unclamped inductive test (EAS = 510 mJ, I_AR = 8.0 A), supporting reliable operation in non-synchronous flyback and resonant converters.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	500 V - Supports 400 V DC bus designs with 25 % voltage margin for transients and ringing.
R_DS(on)	0.85 Ω @ V_GS = 10 V - Enables <1.5 W conduction loss at 4.8 A RMS in 100 kHz SMPS.
Q_g	38 nC - Requires ~0.38 mJ gate drive energy per switch cycle at 10 V, compatible with standard MOSFET drivers.
EAS	510 mJ - Withstands single-pulse inductive energy up to 510 mJ without failure (L = 16 mH, I_AS = 8.0 A).
t_r/t_f	23 ns / 19 ns - Enables <100 ns total switching transition time under R_g = 9.1 Ω, reducing switching loss in hard-switched topologies.
R_thJC	1.0 °C/W - Allows junction temperature rise of only 125 °C at 125 W dissipation, simplifying heatsink sizing.
V_SD	2.0 V @ I_S = 8.0 A - Body diode forward drop impacts synchronous rectification feasibility and reverse recovery loss.

Pinout & Package

D2PAK (TO-263) surface-mount package with isolated copper drain tab (pin 2), gate (pin 1), and source (pin 3) terminals. Thermal pad on underside enables PCB copper pour for enhanced heat transfer.

Pin/Terminal	Circuit Role	Design Meaning
1 (G)	Gate	High-impedance MOSFET control input; requires 10 V drive for full enhancement; Q_gs = 9.0 nC defines Miller threshold timing.
2 (D)	Drain	Main high-voltage power terminal; electrically connected to exposed copper thermal pad; carries full load current and avalanche energy.
3 (S)	Source	Power return and gate reference node; ties to ground plane; body diode anode connects internally to source.

Key Features

Feature	Design Value
Low Q_g	38 nC total gate charge reduces driver power demand and improves switching efficiency in high-frequency SMPS.
Avalanche ruggedness	510 mJ single-pulse energy rating enables reliable operation in non-clamped inductive switching circuits without external snubbers.
Characterized C_oss eff.	56 pF effective output capacitance enables accurate soft-switching timing prediction in resonant LLC and ZVS designs.
Body diode t_rr	422–633 ns reverse recovery time allows use in freewheeling paths where fast diode recovery minimizes cross-conduction loss.
JEDEC TO-263 compliant	D2PAK mechanical outline ensures compatibility with standard SMT reflow profiles and automated assembly equipment.

Applications

Switch Mode Power Supply (SMPS)	Uninterruptible Power Supply (UPS)
Use Scenario: Primary-side switch in 500 W two-transistor forward converter operating at 100 kHz with 400 V DC bus. IC Role / Device Role / Timing Role: High-voltage N-channel power switch handling full primary current and voltage stress; controls energy transfer via PWM duty cycle. Use Value: 500 V V_DS rating and 510 mJ EAS ensure margin against line surges and transformer leakage spikes without derating.	Use Scenario: Inverter stage H-bridge in online double-conversion UPS delivering 1 kVA sinusoidal output. IC Role / Device Role / Timing Role: Half-bridge leg switch managing bidirectional power flow between battery bank and AC output; operates in hard-switched mode. Use Value: 8.0 A continuous current and 125 W P_D support sustained 1 kVA operation with forced-air cooling and minimal heatsink volume.
High-Speed Power Switching	Industrial Motor Drive Stage
Use Scenario: Solid-state relay replacement in programmable logic controller (PLC) output module switching 240 V AC loads. IC Role / Device Role / Timing Role: Fast-turning main power switch isolating control logic from mains-connected load; driven by optocoupled gate driver. Use Value: 23 ns rise time and 19 ns fall time enable sub-microsecond switching transitions, minimizing contact bounce simulation delay.	Use Scenario: Brake chopper switch in 3 kW servo drive dissipating regenerative energy during rapid deceleration. IC Role / Device Role / Timing Role: Energy-dumping switch clamping DC bus voltage during overvoltage events; triggered by bus voltage comparator. Use Value: Repetitive avalanche rating (I_AR = 8.0 A, E_AR = 13 mJ) permits repeated 10 ms energy dumps without degradation.

Switch Mode Power Supply (SMPS)

Uninterruptible Power Supply (UPS)

Use Scenario: Primary-side switch in 500 W two-transistor forward converter operating at 100 kHz with 400 V DC bus.

IC Role / Device Role / Timing Role: High-voltage N-channel power switch handling full primary current and voltage stress; controls energy transfer via PWM duty cycle.

Use Value: 500 V V_DS rating and 510 mJ EAS ensure margin against line surges and transformer leakage spikes without derating.

Use Scenario: Inverter stage H-bridge in online double-conversion UPS delivering 1 kVA sinusoidal output.

IC Role / Device Role / Timing Role: Half-bridge leg switch managing bidirectional power flow between battery bank and AC output; operates in hard-switched mode.

Use Value: 8.0 A continuous current and 125 W P_D support sustained 1 kVA operation with forced-air cooling and minimal heatsink volume.

High-Speed Power Switching

Industrial Motor Drive Stage

Use Scenario: Solid-state relay replacement in programmable logic controller (PLC) output module switching 240 V AC loads.

IC Role / Device Role / Timing Role: Fast-turning main power switch isolating control logic from mains-connected load; driven by optocoupled gate driver.

Use Value: 23 ns rise time and 19 ns fall time enable sub-microsecond switching transitions, minimizing contact bounce simulation delay.

Use Scenario: Brake chopper switch in 3 kW servo drive dissipating regenerative energy during rapid deceleration.

IC Role / Device Role / Timing Role: Energy-dumping switch clamping DC bus voltage during overvoltage events; triggered by bus voltage comparator.

Use Value: Repetitive avalanche rating (I_AR = 8.0 A, E_AR = 13 mJ) permits repeated 10 ms energy dumps without degradation.

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
STP8NK50ZFP	500 V, 7.5 A, R_DS(on) = 0.95 Ω, Q_g = 32 nC, TO-220FP package	Lower peak current but higher R_DS(on); lacks D2PAK thermal performance (R_thJC ≈ 2.5 °C/W)	Prefer when through-hole mounting and lower gate drive energy are prioritized over thermal density.
IXTP8N50D2	500 V, 8.0 A, R_DS(on) = 0.85 Ω, Q_g = 35 nC, TO-220 package	Same electrical specs but TO-220 mechanical form; no exposed drain thermal pad; R_thJC = 1.6 °C/W	Select when legacy board layout prohibits D2PAK footprint or when manual assembly is required.

Compared with STP8NK50ZFP and IXTP8N50D2, the IRF840AL delivers superior thermal management via its D2PAK copper-tab construction (R_thJC = 1.0 °C/W), enabling higher power density in space-constrained SMPS and UPS modules without compromising avalanche reliability.

Availability

IRF840AL is available at Aetrix Electronics and suitable for switch mode power supplies, uninterruptible power systems, and industrial motor control applications requiring stable component supply across long production lifecycles.

Supply support for IRF840AL 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 for industrial, automotive, and computing markets.

The IRF840AL belongs to Vishay's high-voltage power MOSFET product line, engineered for ruggedness and efficiency in off-line AC-DC conversion, UPS inverters, and industrial switching applications demanding 500 V blocking capability and repeatable avalanche performance.

FAQ

What is the maximum continuous drain current for IRF840AL at 100 °C case temperature?

The IRF840AL supports 5.1 A continuous drain current at T_C = 100 °C, as specified in the Absolute Maximum Ratings table. This derating reflects thermal limitations of the D2PAK package and must be applied when heatsink temperature exceeds 25 °C. The IRF840AL maintains R_DS(on) stability up to 150 °C junction temperature, ensuring consistent conduction loss across its full operating range.

Does IRF840AL have a fully characterized body diode, and what are its key recovery parameters?

Yes, the IRF840AL features a fully characterized integral body diode with t_rr = 422–633 ns, Q_rr = 2.0–3.0 μC, and V_SD = 2.0 V at I_S = 8.0 A and T_J = 25 °C. These values are measured under standardized dI/dt = 100 A/μs conditions and directly impact snubber design and cross-conduction loss in half-bridge configurations using the IRF840AL.

What is the gate threshold voltage range for IRF840AL, and how does it affect drive circuit design?

The IRF840AL has a gate threshold voltage V_GS(th) ranging from 2.0 V to 4.0 V at I_D = 250 μA. This wide range necessitates gate drive voltages ≥10 V to ensure full enhancement and minimize R_DS(on) variation across production lots. Using 12 V drive improves noise immunity and guarantees <0.85 Ω on-resistance, critical for thermal stability in the IRF840AL.

Can IRF840AL be used in avalanche mode, and what are the validated limits?

Yes, the IRF840AL is rated for repetitive avalanche operation with I_AR = 8.0 A and E_AR = 13 mJ, and single-pulse avalanche energy E_AS = 510 mJ. These ratings are validated per JEDEC JESD24-11 test conditions (L = 16 mH, R_g = 25 Ω) and apply directly to the IRF840AL without derating. Operation beyond these limits risks parametric shift or catastrophic failure.

What is the thermal resistance from junction to case (R_thJC) for IRF840AL, and how is it measured?

The IRF840AL has a maximum junction-to-case thermal resistance R_thJC of 1.0 °C/W, measured from the silicon die to the exposed drain tab surface of the D2PAK package. This value assumes proper soldering to a 1"² FR-4 PCB copper area and is critical for calculating junction temperature rise in high-power applications using the IRF840AL.

IRF840AL Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

Package/Case:: TO-262-3 Long Leads, I2PAK, TO-262AA

Packaging:: Tube

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 500 V

Current - Continuous Drain (Id) @ 25°C:: 8A (Tc)

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

Rds On (Max) @ Id, Vgs:: 850mOhm @ 4.8A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 38 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 1018 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 3.1W (Ta), 125W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: I2PAK

IRF840AL FAQ

1.How can I place an order for IRF840AL through Aetrix?

Please submit a Request for Quotation (RFQ) for IRF840AL 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 IRF840AL reliable?

The price and inventory of IRF840AL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRF840AL is usually 5 days.

3.What payment methods are accepted for IRF840AL?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRF840AL transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRF840AL?

IRF840AL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRF840AL 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 IRF840AL?

For technical support, including IRF840AL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRF840AL requirements.

6.How does Aetrix verify that IRF840AL is sourced from the original manufacturer or authorized distributors?

All IRF840AL 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 IRF840AL meets industry standards.

7.What is the process for return or replacement of IRF840AL?

All IRF840AL units undergo pre-shipment inspection (PSI). If there is an issue with IRF840AL, 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 IRF840AL part is unused and in its original packaging.

Return procedure for IRF840AL:

1.Submit a request within 90 days.

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

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