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

Vishay Siliconix IRF840L

Name: IRF840L
Brand: Vishay Siliconix
SKU: IRF840L
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRF840L

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: IRF840L.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

IRF840L from Vishay Siliconix is a 500 V, 8.0 A N-channel enhancement-mode power MOSFET in I2PAK (TO-262) package, featuring 0.85 Ω R_DS(on) at V_GS = 10 V, 63 nC total gate charge, and repetitive avalanche rating up to 8.0 A - designed for high-voltage switching in offline SMPS, motor drives, and DC-DC converters.

For engineers reviewing the IRF840L datasheet, IRF840L pinout, IRF840L application, or IRF840L equivalent, key selection criteria include its 500 V V_DS, 125 W P_D at T_C = 25 °C, dV/dt capability of 3.5 V/ns, and body diode t_rr of 460–970 ns - critical for snubberless flyback and inductive load control.

Technical Context

This third-generation silicon power MOSFET uses planar vertical DMOS technology with optimized die layout for low R_DS(on) and fast switching. Its dynamic dV/dt rating and unclamped inductive switching (UIS) capability enable robust operation under transient overvoltage conditions without external clamping.

The device integrates a co-packaged body diode with 8.0 A continuous source-drain current rating and 2.0 V forward voltage at 8 A, supporting synchronous rectification and freewheeling functions in hard-switched topologies where reverse recovery behavior directly impacts EMI and efficiency.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	500 V - supports primary-side switching in universal-input 85–265 VAC offline converters without derating.
R_DS(on) @ V_GS = 10 V	0.85 Ω - limits conduction loss to ≤ 6.9 W at 9.2 A RMS in 50 kHz half-bridge applications.
Q_g	63 nC - determines gate drive power requirement (~1.3 mW per MHz at 10 V drive) and influences switching speed trade-off.
I_D (T_C = 25 °C)	8.0 A - defines maximum continuous current handling with heatsink; derates linearly to 5.1 A at 100 °C case temperature.
E_AS	510 mJ - enables reliable operation during single-pulse inductive energy dump (e.g., relay coil de-energization) without failure.
t_rr (body diode)	460–970 ns - impacts turn-off losses and voltage overshoot in freewheeling paths; requires careful snubber design above 100 kHz.
R_thJC	1.0 °C/W - allows junction temperature rise of only 125 °C at full 125 W dissipation, enabling compact thermal design with minimal copper area.

Pinout & Package

I2PAK (TO-262) package with isolated drain tab, 3-pin through-hole compatible footprint, and 1.0 °C/W junction-to-case thermal resistance. Mounting surface must be electrically isolated and thermally coupled to heatsink via thermal pad or compound.

Pin/Terminal	Circuit Role	Design Meaning
Drain (D)	Main high-side current path	Connected to internal die backside; electrically tied to metal tab - requires isolation from PCB ground plane unless system ground referenced.
Gate (G)	Control electrode	High-impedance MOS input; requires <100 nA leakage drive; sensitive to ESD - needs series resistor (9.1 Ω typical) and local bypass capacitor.
Source (S)	Reference node for gate drive and current sensing	Low-inductance return path; internal source bond wires contribute 7.5 nH inductance - impacts dI/dt-induced V_GS ringing during fast switching.

Key Features

Feature	Design Value
Repetitive avalanche rated	Withstands 8.0 A repetitive avalanche current (I_AR) and 13 mJ energy (E_AR) - eliminates need for external avalanche protection in motor phase-legs.
Dynamic dV/dt rating	3.5 V/ns - prevents false turn-on during high dv/dt transients in bridge configurations without requiring negative gate bias.
Halogen-free & RoHS-compliant	Meets JEDEC JS709A halogen-free standard and EU Directive 2011/65/EU - suitable for consumer and industrial products with strict material compliance requirements.
Fast switching with low Q_gd/Q_g ratio	Q_gd = 32 nC / Q_g = 63 nC ≈ 0.51 - improves Miller immunity and reduces switching transition time in hard-switched converters.
Easy paralleling capability	Positive temperature coefficient of R_DS(on) (see Fig. 4) ensures current sharing stability across multiple IRF840L devices in parallel arrays.

Applications

Offline AC-DC Power Supplies	DC Motor Drives
Use Scenario: Primary-side switch in 30–100 W flyback converters operating from 85–265 VAC input. IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer into transformer primary winding during PWM on-time. Use Value: 500 V V_DS margin accommodates reflected output voltage + leakage spike + line surge; 0.85 Ω R_DS(on) keeps conduction loss below 1.5 W at full load.	Use Scenario: Half-bridge high-side switch driving brushed DC motors in industrial actuators and HVAC blowers. IC Role / Device Role / Timing Role: Unidirectional power switch enabling bidirectional motor rotation when paired with low-side complement. Use Value: Repetitive avalanche rating absorbs inductive kickback during PWM commutation; 8.0 A I_D supports 12 V/5 A motor loads with 2× safety margin.
Inductive Load Switching	DC-DC Boost Converters
Use Scenario: Solid-state relay replacement for solenoid, relay, and transformer primary switching in PLC output modules. IC Role / Device Role / Timing Role: Single-pole, single-throw (SPST) power switch controlling inductive load energization/de-energization cycles. Use Value: 510 mJ single-pulse avalanche energy handles 100 mJ+ inductive stored energy without clamping; 3.5 V/ns dV/dt rating suppresses spurious turn-on.	Use Scenario: Main switch in 12 V–24 V input, 48 V output boost converter for telecom power systems. IC Role / Device Role / Timing Role: High-side switch accumulating energy in boost inductor during on-time and releasing it to output capacitor during off-time. Use Value: Low Q_g (63 nC) enables efficient 200 kHz operation; 125 W P_D supports >150 W peak power bursts during transient load steps.

Offline AC-DC Power Supplies

DC Motor Drives

Use Scenario: Primary-side switch in 30–100 W flyback converters operating from 85–265 VAC input.

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

Use Value: 500 V V_DS margin accommodates reflected output voltage + leakage spike + line surge; 0.85 Ω R_DS(on) keeps conduction loss below 1.5 W at full load.

Use Scenario: Half-bridge high-side switch driving brushed DC motors in industrial actuators and HVAC blowers.

IC Role / Device Role / Timing Role: Unidirectional power switch enabling bidirectional motor rotation when paired with low-side complement.

Use Value: Repetitive avalanche rating absorbs inductive kickback during PWM commutation; 8.0 A I_D supports 12 V/5 A motor loads with 2× safety margin.

Inductive Load Switching

DC-DC Boost Converters

Use Scenario: Solid-state relay replacement for solenoid, relay, and transformer primary switching in PLC output modules.

IC Role / Device Role / Timing Role: Single-pole, single-throw (SPST) power switch controlling inductive load energization/de-energization cycles.

Use Value: 510 mJ single-pulse avalanche energy handles 100 mJ+ inductive stored energy without clamping; 3.5 V/ns dV/dt rating suppresses spurious turn-on.

Use Scenario: Main switch in 12 V–24 V input, 48 V output boost converter for telecom power systems.

IC Role / Device Role / Timing Role: High-side switch accumulating energy in boost inductor during on-time and releasing it to output capacitor during off-time.

Use Value: Low Q_g (63 nC) enables efficient 200 kHz operation; 125 W P_D supports >150 W peak power bursts during transient load steps.

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
STP5NK50ZFP	500 V, 4.5 A, R_DS(on) = 1.4 Ω, Zener-protected gate, TO-220FP package	Lower current rating and higher R_DS(on); integrated gate protection reduces external TVS need but increases cost	Preferred where gate robustness outweighs conduction loss; not drop-in due to lower I_D and different thermal profile
FQP5N50C	500 V, 4.5 A, R_DS(on) = 1.4 Ω, TO-220 package, no avalanche rating	No UIS or repetitive avalanche specification; lacks dV/dt immunity data; lower thermal mass than I2PAK	Suitable for non-critical, low-duty-cycle switching; avoid in inductive or high-dv/dt environments where IRF840L's ruggedness is essential

Compared with STP5NK50ZFP and FQP5N50C, the IRF840L delivers higher continuous current (8.0 A vs. 4.5 A), lower on-resistance (0.85 Ω vs. 1.4 Ω), and verified repetitive avalanche capability - making it the preferred choice for sustained high-power, high-reliability switching where thermal and transient robustness are mandatory.

Availability

IRF840L is available at Aetrix Electronics and suitable for offline AC-DC power supplies, DC motor drives, and inductive load switching requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for IRF840L 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 and passive components, specializing in high-reliability power MOSFETs, diodes, and optoelectronics for industrial, automotive, and computing markets.

The IRF840L belongs to Vishay's third-generation power MOSFET family engineered for high-voltage switching efficiency and ruggedness in offline power conversion and motor control - emphasizing avalanche survivability, dynamic dV/dt immunity, and ease of thermal management.

FAQ

What is the maximum continuous drain current for IRF840L at 100 °C case temperature?

The IRF840L 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 I2PAK package; operation above this current requires active cooling or reduced duty cycle to maintain T_J ≤ 150 °C. The IRF840L datasheet confirms this value under "Continuous Drain Current" with footnote indicating TC = 100 °C condition.

Does IRF840L have a built-in body diode, and what are its key parameters?

Yes, the IRF840L integrates a parasitic body diode inherent to its vertical N-channel MOSFET structure. Key parameters include 8.0 A continuous source-drain current (I_S), 32 A pulsed rating (I_SM), 2.0 V forward voltage (V_SD) at 8 A and 25 °C, and reverse recovery time (t_rr) of 460–970 ns. These values are measured per the test conditions in the IRF840L datasheet section "Drain-Source Body Diode Characteristics".

Is IRF840L suitable for use in avalanche mode, and what energy level is rated?

Yes, the IRF840L is explicitly 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 test conditions in the datasheet (note b: V_DD = 50 V, L = 14 mH, R_g = 25 Ω, I_AS = 8.0 A). Designers must ensure pulse width and duty cycle remain within limits defined in Figure 11 to avoid junction overheating during IRF840L avalanche events.

What is the gate threshold voltage range for IRF840L, and how does it affect drive requirements?

The IRF840L has a gate-source threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V at I_D = 250 μA, meaning it begins conducting weakly at ~2 V and achieves full enhancement near 10 V. This standard-threshold characteristic requires a minimum 10 V gate drive for low R_DS(on) operation; logic-level drivers (e.g., 3.3 V or 5 V) cannot fully turn on the IRF840L and will cause excessive conduction loss. The IRF840L datasheet specifies this in the "Static" subsection of "Specifications".

How does the IRF840L's R_DS(on) change with temperature, and why does that matter in design?

The IRF840L exhibits a positive temperature coefficient for R_DS(on): normalized resistance increases with junction temperature, reaching ~1.8× its 25 °C value at 150 °C (per Figure 4). This behavior improves current sharing in parallel configurations and provides inherent thermal stability - preventing thermal runaway during overload. Designers must account for elevated R_DS(on) at high T_J when calculating worst-case conduction loss; the IRF840L datasheet provides the exact curve in "Typical Characteristics".

IRF840L 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:: 63 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 1300 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:: I2PAK

IRF840L FAQ

1.How can I place an order for IRF840L through Aetrix?

Please submit a Request for Quotation (RFQ) for IRF840L 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 IRF840L reliable?

The price and inventory of IRF840L are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRF840L is usually 5 days.

3.What payment methods are accepted for IRF840L?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRF840L transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRF840L?

IRF840L orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRF840L 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 IRF840L?

For technical support, including IRF840L datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRF840L requirements.

6.How does Aetrix verify that IRF840L is sourced from the original manufacturer or authorized distributors?

All IRF840L 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 IRF840L meets industry standards.

7.What is the process for return or replacement of IRF840L?

All IRF840L units undergo pre-shipment inspection (PSI). If there is an issue with IRF840L, 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 IRF840L part is unused and in its original packaging.

Return procedure for IRF840L:

1.Submit a request within 90 days.

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

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