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

Vishay Siliconix IRF634

Name: IRF634
Brand: Vishay Siliconix
SKU: IRF634
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRF634

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: TO-220-3

Datasheet:: IRF634.pdf

Description:: MOSFET N-CH 250V 8.1A TO220AB

Quantity:: RFQ Add To RFQ list

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Product details

Overview

IRF634 from Vishay Siliconix is a 250 V, 8.1 A N-channel power MOSFET in TO-220AB package, optimized for switch-mode power supplies, motor controls, and DC-DC converters with fast switching, repetitive avalanche rating, and low 0.45 Ω R_DS(on) at V_GS = 10 V.

For engineers reviewing the IRF634 datasheet, IRF634 pinout, IRF634 application, or IRF634 equivalent, key selection criteria include its 250 V V_DS, 41 nC total gate charge, 300 mJ single-pulse avalanche energy, TO-220AB thermal performance (R_thJC = 1.7 °C/W), and body diode recovery time of 220–440 ns.

Technical Context

The IRF634 uses third-generation planar vertical DMOS technology to deliver ruggedized operation with dynamic dV/dt immunity up to 4.8 V/ns and guaranteed repetitive avalanche capability at 8.1 A. Its gate threshold voltage (2.0–4.0 V) supports standard 10 V logic-level drive while maintaining low leakage (±100 nA I_GSS).

Thermal design is enabled by low junction-to-case resistance (1.7 °C/W) and linear derating (0.59 W/°C above 25 °C), allowing stable 74 W dissipation at T_C = 25 °C. The integral body diode exhibits 2.0 V forward drop at 8.1 A and controlled reverse recovery (Q_rr = 1.2–2.4 μC) for snubberless inductive switching.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	250 V - supports 200 V bus designs with 25 % margin for transients
R_DS(on) @ V_GS = 10 V	0.45 Ω - enables <1.9 W conduction loss at 5.1 A continuous current
Q_g	41 nC - determines gate driver power requirement and switching speed trade-off
E_AS	300 mJ - allows unclamped inductive switching without failure under defined test conditions
dV/dt Rating	4.8 V/ns - ensures noise immunity in high-dI/dt environments like motor drives
T_J Range	−55 to +150 °C - supports industrial and automotive under-hood ambient conditions
I_D @ T_C = 100 °C	5.1 A - defines usable current in thermally constrained heatsink layouts

Pinout & Package

TO-220AB package with isolated tab (drain-connected), standard 3-lead through-hole mounting, 1.7 °C/W junction-to-case thermal resistance, and 62 °C/W junction-to-ambient (no heatsink).

Pin/Terminal	Circuit Role	Design Meaning
Drain (Tab)	Main current path output / heat sink interface	Electrically connected to metal tab; requires insulating washer if mounted to grounded heatsink
Gate	Control input for channel conduction	High-impedance MOS gate; 6.5 nC Q_gs enables simple resistor-based drive
Source	Reference node for gate drive and load return	Completes power loop; internal source inductance (7.5 nH) affects high-speed switching ringing

Key Features

Feature	Design Value
Repetitive avalanche rated	Enables reliable operation in inductive switching without external clamping circuits
Dynamic dV/dt rating (4.8 V/ns)	Prevents false turn-on during high-slew-rate voltage transients in bridge configurations
Low Q_gd/Q_g ratio (22/41 nC)	Reduces Miller effect, improving hard-switching robustness and reducing gate drive losses
RoHS-compliant Pb-free variant (IRF634PbF)	Meets global environmental compliance without sacrificing electrical or thermal performance
Fast body diode recovery (t_rr = 220–440 ns)	Minimizes reverse recovery losses in synchronous rectification and freewheeling paths

Applications

Switch-Mode Power Supply (SMPS)	Motor Drive Half-Bridge
Use Scenario: Primary-side switching in 100–200 W offline flyback or forward converters. IC Role / Device Role / Timing Role: High-voltage N-channel power switch controlling energy transfer via transformer primary winding. Use Value: 250 V V_DS and 300 mJ E_AS tolerate reflected output transients and startup surges without snubber.	Use Scenario: Low-side switch in brushed DC motor H-bridge for industrial actuators. IC Role / Device Role / Timing Role: Ground-referenced power switch enabling bidirectional current control with PWM duty cycle modulation. Use Value: 8.1 A continuous drain current and 4.8 V/ns dV/dt rating prevent shoot-through during fast commutation.
DC-DC Buck Converter	Inductive Load Switching
Use Scenario: High-side switch in 24–48 V input buck regulators for telecom or industrial systems. IC Role / Device Role / Timing Role: Main power transistor regulating output voltage by modulating duty cycle at 100–500 kHz. Use Value: 0.45 Ω R_DS(on) limits conduction loss to <2 W at 5.1 A, supporting >92 % efficiency at full load.	Use Scenario: Solenoid or relay driver in programmable logic controller (PLC) output modules. IC Role / Device Role / Timing Role: Robust load switch handling inductive kickback during de-energization. Use Value: Repetitive avalanche rating (I_AR = 8.1 A, E_AR = 7.4 mJ) absorbs stored energy without external TVS.

Switch-Mode Power Supply (SMPS)

Motor Drive Half-Bridge

Use Scenario: Primary-side switching in 100–200 W offline flyback or forward converters.

IC Role / Device Role / Timing Role: High-voltage N-channel power switch controlling energy transfer via transformer primary winding.

Use Value: 250 V V_DS and 300 mJ E_AS tolerate reflected output transients and startup surges without snubber.

Use Scenario: Low-side switch in brushed DC motor H-bridge for industrial actuators.

IC Role / Device Role / Timing Role: Ground-referenced power switch enabling bidirectional current control with PWM duty cycle modulation.

Use Value: 8.1 A continuous drain current and 4.8 V/ns dV/dt rating prevent shoot-through during fast commutation.

DC-DC Buck Converter

Inductive Load Switching

Use Scenario: High-side switch in 24–48 V input buck regulators for telecom or industrial systems.

IC Role / Device Role / Timing Role: Main power transistor regulating output voltage by modulating duty cycle at 100–500 kHz.

Use Value: 0.45 Ω R_DS(on) limits conduction loss to <2 W at 5.1 A, supporting >92 % efficiency at full load.

Use Scenario: Solenoid or relay driver in programmable logic controller (PLC) output modules.

IC Role / Device Role / Timing Role: Robust load switch handling inductive kickback during de-energization.

Use Value: Repetitive avalanche rating (I_AR = 8.1 A, E_AR = 7.4 mJ) absorbs stored energy without external TVS.

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
STP20NM50FP	500 V V_DS, 0.23 Ω R_DS(on), TO-220FP package (full-pack, insulated tab)	Higher voltage rating but lower on-resistance; requires different heatsink isolation approach	Preferred when 500 V bus tolerance or lower conduction loss is critical; not drop-in due to insulated tab
IXTP12N25P	250 V V_DS, 0.28 Ω R_DS(on), TO-220 package, 22 nC Q_g	Lower gate charge and on-resistance, but no specified repetitive avalanche rating	Selected for higher efficiency in high-frequency SMPS where avalanche stress is managed externally

Compared with STP20NM50FP and IXTP12N25P, the IRF634 offers verified repetitive avalanche capability and proven dV/dt immunity at 250 V, making it preferred for cost-sensitive industrial power stages where ruggedness outweighs marginal R_DS(on) or Q_g improvements.

Availability

IRF634 is available at Aetrix Electronics and suitable for switch-mode power supplies, motor drives, DC-DC converters, and industrial solenoid control requiring stable component supply across long-lifecycle production programs.

Supply support for IRF634 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 power MOSFETs, diodes, and optoelectronics with emphasis on reliability and ruggedness.

The IRF634 belongs to Vishay's third-generation power MOSFET family, engineered for high-voltage industrial switching applications demanding avalanche robustness, fast switching, and thermal stability in TO-220 packages.

FAQ

What is the maximum continuous drain current for IRF634 at 100 °C case temperature?

The IRF634 supports 5.1 A continuous drain current at T_C = 100 °C, derived from its 8.1 A rating at 25 °C and linear derating factor of 0.59 W/°C. This value reflects real thermal limits under sustained conduction, not pulsed operation. Designers must verify heatsink performance to maintain T_C ≤ 100 °C for reliable IRF634 operation in continuous-duty applications.

Does IRF634 have a fully rated avalanche capability, and how is it specified?

Yes, the IRF634 is explicitly repetitive avalanche rated per its datasheet: I_AR = 8.1 A and E_AR = 7.4 mJ under defined pulse conditions. It also specifies 300 mJ single-pulse avalanche energy (E_AS) with test conditions (V_DD = 50 V, L = 7.3 mH, R_g = 25 Ω). These values are measured and guaranteed-not typical estimates-making IRF634 suitable for unclamped inductive switching without external protection.

What is the gate threshold voltage range for IRF634, and how does it affect drive requirements?

The IRF634 has a gate threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V at I_D = 250 μA. This ensures reliable turn-on with standard 5 V or 10 V logic-level drivers while avoiding unintended conduction from noise. Its 6.5 nC Q_gs and 41 nC Q_g allow straightforward resistor-based gate drive, and the device is not a logic-level MOSFET-optimal enhancement occurs at V_GS ≥ 10 V for minimal R_DS(on).

How does the IRF634 body diode perform in freewheeling applications?

The IRF634 body diode delivers 8.1 A continuous forward current with a 2.0 V forward voltage (V_SD) at 25 °C and 8.1 A. Its reverse recovery time (t_rr) is 220–440 ns, and recovered charge (Q_rr) is 1.2–2.4 μC-values confirmed in the datasheet under standardized test conditions. These characteristics make the IRF634 suitable for moderate-frequency freewheeling in buck converters and motor drives, though synchronous rectification may be preferred above 200 kHz.

Is IRF634PbF a direct replacement for legacy IRF634 with leaded terminations?

Yes, IRF634PbF is the RoHS-compliant, lead-free version of the IRF634, sharing identical electrical specifications, thermal performance, and mechanical dimensions per Vishay's S21-0340 datasheet. No PCB layout or thermal design changes are required when migrating from leaded to IRF634PbF, and both variants use the same TO-220AB package with drain-connected tab and identical pinout.

IRF634 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):: 250 V

Current - Continuous Drain (Id) @ 25°C:: 8.1A (Tc)

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

Rds On (Max) @ Id, Vgs:: 450mOhm @ 5.1A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 41 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 770 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 74W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220AB

IRF634 FAQ

1.How can I place an order for IRF634 through Aetrix?

Please submit a Request for Quotation (RFQ) for IRF634 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 IRF634 reliable?

The price and inventory of IRF634 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRF634 is usually 5 days.

3.What payment methods are accepted for IRF634?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRF634 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRF634?

IRF634 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRF634 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 IRF634?

For technical support, including IRF634 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRF634 requirements.

6.How does Aetrix verify that IRF634 is sourced from the original manufacturer or authorized distributors?

All IRF634 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 IRF634 meets industry standards.

7.What is the process for return or replacement of IRF634?

All IRF634 units undergo pre-shipment inspection (PSI). If there is an issue with IRF634, 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 IRF634 part is unused and in its original packaging.

Return procedure for IRF634:

1.Submit a request within 90 days.

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

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