Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Vishay Siliconix IRF840LCS

Name: IRF840LCS
Brand: Vishay Siliconix
SKU: IRF840LCS
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: IRF840LCS

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: IRF840LCS.pdf

Description:: MOSFET N-CH 500V 8A D2PAK

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,582

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

IRF840LCS from Vishay Siliconix is a 500 V, 8.0 A N-channel power MOSFET in D2PAK (TO-263) package, featuring 0.85 Ω R_DS(on) at V_GS = 10 V, 39 nC total gate charge, and repetitive avalanche rating-designed for high-frequency switch-mode power supplies, DC-DC converters, and motor control circuits requiring robust unclamped inductive switching capability.

For engineers reviewing the IRF840LCS datasheet, IRF840LCS pinout, IRF840LCS application, or IRF840LCS equivalent, this device delivers verified ultra-low gate charge (39 nC), enhanced ±30 V gate rating, reduced C_iss/C_oss/C_rss, and 510 mJ single-pulse avalanche energy-critical for evaluating high-efficiency, high-reliability hard-switched topologies.

Technical Context

This device employs Vishay's LCDMOS (Low Charge Device MOSFET) technology to achieve significantly lower gate charge versus conventional power MOSFETs without added cost. Its 39 nC Q_g, 10 nC Q_gs, and 19 nC Q_gd enable reduced gate drive requirements and faster switching transitions-evidenced by t_d(on) = 12 ns, t_r = 25 ns, t_d(off) = 27 ns, and t_f = 19 ns under standardized test conditions (V_DD = 250 V, I_D = 8.0 A, R_g = 9.1 Ω).

The IRF840LCS integrates a rugged body diode with t_rr = 490–740 ns, Q_rr = 3.0–4.5 μC, and peak dV/dt capability of 3.5 V/ns-enabling reliable operation in freewheeling and synchronous rectification roles where fast, controlled diode recovery is essential.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	500 V - supports primary-side switching in offline SMPS up to 400 V DC bus with margin
R_DS(on)	0.85 Ω @ V_GS = 10 V - enables low conduction loss at 8.0 A continuous drain current (T_C = 25 °C)
Q_g	39 nC - reduces gate driver power demand and allows use of smaller, lower-cost drivers
E_AS	510 mJ - provides validated single-pulse avalanche energy handling for unclamped inductive loads
T_J Range	−55 to +150 °C - ensures stable operation across industrial and automotive ambient environments
R_thJC	1.0 °C/W - enables high-power dissipation (125 W at T_C = 25 °C) with minimal thermal resistance to heatsink
V_GS(th)	2.0–4.0 V - compatible with standard 5 V and 10 V logic-level gate drivers

Pinout & Package

D2PAK (TO-263) surface-mount package with exposed drain pad for thermal and electrical connection; 3-terminal configuration optimized for high-current, high-voltage PCB layouts.

Pin/Terminal	Circuit Role	Design Meaning
G (Gate)	Control input	Receives voltage-controlled signal to modulate channel conductivity; requires <±30 V rating per datasheet
D (Drain)	High-side power output	Connected to high-voltage rail (up to 500 V); electrically and thermally tied to exposed backside metal pad
S (Source)	Reference/return node	Serves as common return path for load current and gate drive reference; defines V_GS measurement point

Key Features

Feature	Design Value
Ultra-low gate charge (39 nC)	Reduces gate driver IC power consumption and heat generation in high-frequency (>100 kHz) applications
Enhanced ±30 V V_GS rating	Prevents gate oxide damage during transient overvoltage events and improves system robustness
Reduced C_iss/C_oss/C_rss	Lowers switching losses and EMI generation-C_iss = 1100 pF, C_oss = 170 pF, C_rss = 18 pF at V_DS = 25 V
Repetitive avalanche rated	Supports reliable operation under repeated inductive turn-off stress (I_AR = 8.0 A, E_AR = 13 mJ)
Low R_DS(on) × Q_g figure-of-merit	Optimizes trade-off between conduction and switching losses in hard-switched converters

Applications

Switch-Mode Power Supply	DC-DC Converter
Use Scenario: Primary-side switching in 50–200 W offline flyback and forward converters. IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer from AC line to transformer primary. Use Value: 500 V V_DS and 510 mJ E_AS ensure safe operation during output short-circuit and startup transients.	Use Scenario: High-side switch in isolated or non-isolated buck-derived topologies for industrial 24 V/48 V systems. IC Role / Device Role / Timing Role: Main power transistor regulating output voltage via PWM duty cycle control. Use Value: 0.85 Ω R_DS(on) and 39 nC Q_g minimize combined conduction and switching losses at 200–500 kHz switching frequencies.
Motor Drive	Lighting Ballast
Use Scenario: Half-bridge leg in 100–500 W BLDC motor controllers for HVAC blowers and power tools. IC Role / Device Role / Timing Role: High-side switching element in bridge configuration managing phase current commutation. Use Value: Repetitive avalanche rating (E_AR = 13 mJ) withstands inductive kickback during PWM dead-time transitions.	Use Scenario: Resonant switch in electronic CFL and LED driver ballasts operating above 20 kHz. IC Role / Device Role / Timing Role: Fast-switching power transistor enabling zero-voltage switching (ZVS) in half-bridge resonant tanks. Use Value: Low C_rss (18 pF) and fast switching times (t_f = 19 ns) reduce capacitive feedthrough and improve ZVS margin.

Switch-Mode Power Supply

DC-DC Converter

Use Scenario: Primary-side switching in 50–200 W offline flyback and forward converters.

IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer from AC line to transformer primary.

Use Value: 500 V V_DS and 510 mJ E_AS ensure safe operation during output short-circuit and startup transients.

Use Scenario: High-side switch in isolated or non-isolated buck-derived topologies for industrial 24 V/48 V systems.

IC Role / Device Role / Timing Role: Main power transistor regulating output voltage via PWM duty cycle control.

Use Value: 0.85 Ω R_DS(on) and 39 nC Q_g minimize combined conduction and switching losses at 200–500 kHz switching frequencies.

Motor Drive

Lighting Ballast

Use Scenario: Half-bridge leg in 100–500 W BLDC motor controllers for HVAC blowers and power tools.

IC Role / Device Role / Timing Role: High-side switching element in bridge configuration managing phase current commutation.

Use Value: Repetitive avalanche rating (E_AR = 13 mJ) withstands inductive kickback during PWM dead-time transitions.

Use Scenario: Resonant switch in electronic CFL and LED driver ballasts operating above 20 kHz.

IC Role / Device Role / Timing Role: Fast-switching power transistor enabling zero-voltage switching (ZVS) in half-bridge resonant tanks.

Use Value: Low C_rss (18 pF) and fast switching times (t_f = 19 ns) reduce capacitive feedthrough and improve ZVS margin.

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
IRF840LCSPbF	Same silicon die and electrical specs; Pb-containing terminations instead of Pb-free (RoHS exemption)	Identical performance in all circuit roles; restricted to non-RoHS-compliant designs	Select when legacy leaded assembly or specific regulatory exemptions apply
SiHF840LCS-GE3	Identical specifications and D2PAK package; Vishay's fully RoHS-compliant, halogen-free variant	No functional difference; qualified for green manufacturing and export compliance	Preferred for new designs requiring full environmental compliance

Compared with IRF840LCS, IRF840LCSPbF offers identical electrical and thermal behavior but lacks RoHS compliance, while SiHF840LCS-GE3 delivers identical performance with certified Pb-free/halogen-free construction-making it the direct drop-in replacement for environmentally regulated production.

Availability

IRF840LCS is available at Aetrix Electronics and suitable for switch-mode power supplies, DC-DC converters, and motor control systems requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for IRF840LCS 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 demanding industrial and power applications.

The IRF840LCS belongs to Vishay's LCDMOS low-charge power MOSFET family-engineered specifically for high-frequency, high-efficiency switching in SMPS, UPS, and motor drives where gate drive efficiency and avalanche ruggedness are critical.

FAQ

What is the maximum continuous drain current for IRF840LCS at 100 °C case temperature?

The IRF840LCS 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 ensures junction temperature remains within the −55 to +150 °C operating range. Designers must verify heatsinking to maintain T_C ≤ 100 °C under full-load conditions to sustain this current rating in the IRF840LCS.

Does IRF840LCS have a built-in body diode, and what are its key recovery parameters?

Yes, the IRF840LCS integrates a monolithic body diode with typical reverse recovery time (t_rr) of 490–740 ns and reverse recovery charge (Q_rr) of 3.0–4.5 μC at T_J = 25 °C, I_F = 8.0 A, and dI/dt = 100 A/μs. These values are measured per the test conditions in the datasheet and directly impact snubber design and EMI in freewheeling applications using the IRF840LCS.

What is the gate threshold voltage range for IRF840LCS, and how does it affect drive compatibility?

The IRF840LCS has a gate threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V at I_D = 250 μA. This allows reliable turn-on with standard 5 V logic-level drivers while maintaining noise immunity. Full enhancement to R_DS(on) = 0.85 Ω requires V_GS ≥ 10 V, confirming that the IRF840LCS is not a logic-level MOSFET but remains compatible with widely available 10 V gate drivers.

Can IRF840LCS be used in avalanche mode, and what are the limits?

Yes, the IRF840LCS is rated for both single-pulse (E_AS = 510 mJ) and repetitive avalanche (E_AR = 13 mJ, I_AR = 8.0 A). These ratings are validated per test conditions in Figures 11–12 of the datasheet and apply only when pulse width and duty cycle remain within specified limits. Safe avalanche operation of the IRF840LCS requires strict adherence to the linear derating factor (1.0 W/°C) and thermal management guidelines.

What is the thermal resistance from junction to case (R_thJC) for IRF840LCS, and why does it matter?

The IRF840LCS has a maximum junction-to-case thermal resistance (R_thJC) of 1.0 °C/W, measured from the silicon die to the exposed drain pad. This low value enables efficient heat transfer to an external heatsink and supports the device's 125 W maximum power dissipation at T_C = 25 °C. Accurate thermal modeling of the IRF840LCS must use this R_thJC value-not R_thJA-when heatsink attachment is implemented.

IRF840LCS 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):: 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:: 39 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 1100 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)

IRF840LCS FAQ

1.How can I place an order for IRF840LCS through Aetrix?

Please submit a Request for Quotation (RFQ) for IRF840LCS 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 IRF840LCS reliable?

The price and inventory of IRF840LCS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRF840LCS is usually 5 days.

3.What payment methods are accepted for IRF840LCS?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRF840LCS transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRF840LCS?

IRF840LCS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRF840LCS 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 IRF840LCS?

For technical support, including IRF840LCS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRF840LCS requirements.

6.How does Aetrix verify that IRF840LCS is sourced from the original manufacturer or authorized distributors?

All IRF840LCS 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 IRF840LCS meets industry standards.

7.What is the process for return or replacement of IRF840LCS?

All IRF840LCS units undergo pre-shipment inspection (PSI). If there is an issue with IRF840LCS, 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 IRF840LCS part is unused and in its original packaging.

Return procedure for IRF840LCS:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-10 Schmitt Trigger Explained: Hysteresis, Circuits, Inverters and Applications

Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…