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 IRFI644G

Name: IRFI644G
Brand: Vishay Siliconix
SKU: IRFI644G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: IRFI644G

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: TO-220-3 Full Pack, Isolated Tab

Datasheet:: IRFI644G.pdf

Description:: MOSFET N-CH 250V 7.9A TO220-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,890

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

Product details

Overview

IRFI644G from Vishay Siliconix is a 250 V, 7.9 A N-channel power MOSFET in an isolated TO-220 FULLPAK package, featuring 0.28 Ω R_DS(on) at V_GS = 10 V, 68 nC total gate charge, and 2.5 kV_RMS isolation for high-voltage industrial switching applications such as AC/DC SMPS primary-side switches and motor drive half-bridges.

For engineers reviewing the IRFI644G datasheet, IRFI644G pinout, IRFI644G application, or IRFI644G equivalent, this device is selected for high-reliability, thermally efficient, insulated-gate switching where creepage distance (4.8 mm), avalanche ruggedness (600 mJ single-pulse), and low thermal resistance (3.1 °C/W junction-to-case) are critical design constraints.

Technical Context

The IRFI644G employs a third-generation silicon process optimized for fast switching and ruggedized avalanche performance, with dynamic dV/dt rating of 4.8 V/ns and body diode reverse recovery time (trr) of 250–500 ns under specified conditions. Its isolated TO-220 FULLPAK construction eliminates need for external insulators in commercial-industrial systems.

Thermal design is enabled by low R_thJC = 3.1 °C/W and high isolation voltage (2.5 kV_RMS, 60 s), while gate drive compatibility is ensured by V_GS(th) = 2.0–4.0 V and Q_g = 68 nC - supporting standard 10 V gate drivers without requiring level-shifting or specialized buffers.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	250 V - supports primary-side switching in 230 VAC offline converters with margin for surge and ringing.
R_DS(on) @ V_GS = 10 V	0.28 Ω - enables <7.9 A continuous conduction with ≤17.5 W conduction loss at T_C = 25 °C.
Q_g	68 nC - determines gate drive power requirement; compatible with common 1-A peak gate drivers at ≤100 kHz.
E_AS	600 mJ - ensures single-pulse avalanche survivability during inductive turn-off transients in motor or relay loads.
R_thJC	3.1 °C/W - allows 40 W power dissipation with ≤125 °C junction rise above 25 °C case temperature.
dV/dt Rating	4.8 V/ns - suppresses false turn-on in high-noise environments like variable-frequency drives and welders.
V_ISOL	2.5 kV_RMS (60 s) - replaces mica washers in TO-220 mounting, simplifying heatsink insulation in Class I equipment.

Pinout & Package

IRFI644G uses the TO-220 FULLPAK package: isolated plastic housing with integral heatsink tab (drain-connected), 3-pin through-hole configuration, and 4.8 mm sink-to-lead creepage distance. Dimensions conform to Vishay Doc. #91359 (Option 1 or 2, facility code dependent).

Pin/Terminal	Circuit Role	Design Meaning
Drain (Tab)	Main current path output / heatsink interface	Electrically connected to exposed metal tab; must be mounted to heatsink with electrically isolating hardware only if system grounding requires it - tab is functional drain node.
Gate	Control input	High-impedance MOS gate requiring <±20 V absolute max; typical 10 V drive yields full enhancement; threshold 2.0–4.0 V enables compatibility with microcontroller GPIOs via buffer.
Source	Reference return / current sense node	Common return for load current and gate drive reference; low-inductance layout critical due to LS = 7.5 nH; used for current sensing in high-side configurations.

Key Features

Feature	Design Value
Isolated TO-220 FULLPAK package	Eliminates external insulating hardware (e.g., mica + grease) - reduces BOM count and assembly steps in AC mains-connected power supplies.
2.5 kV_RMS isolation	Validated per IEC 60747-5-2; enables direct mounting to grounded heatsinks in Class I safety designs without compromising creepage/clearance.
Low R_thJC = 3.1 °C/W	Enables higher power density vs. standard TO-220: 40 W dissipation achievable with modest heatsinking at T_C = 100 °C.
Body diode t_rr = 250–500 ns	Supports synchronous rectification and freewheeling in hard-switched topologies without excessive switching loss or voltage overshoot.
Avalanche-rated (E_AS = 600 mJ)	Guarantees robustness against inductive kickback in relay drivers, solenoid controls, and motor phase-leg switching without snubbers.

Applications

Industrial AC/DC Power Supplies	Motor Drive Half-Bridge Legs
Use Scenario: Primary-side switch in 100–300 W offline flyback or forward converters operating from 85–265 VAC input. IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer into transformer primary; operates at 65–130 kHz with hard switching. Use Value: 250 V V_DS and 600 mJ E_AS provide margin for line surges and transformer leakage spikes; 0.28 Ω R_DS(on) limits conduction loss at full load.	Use Scenario: Upper or lower switch in 3-phase inverter stages for BLDC or stepper motor control up to 1 kW. IC Role / Device Role / Timing Role: N-channel power switch in half-bridge topology; driven by isolated gate driver with bootstrap or transformer coupling. Use Value: 4.8 V/ns dV/dt rating prevents spurious turn-on during high dv/dt cross-conduction; TO-220 FULLPAK isolation simplifies heatsink sharing across phases.
Inductive Load Switching (Relays/Solenoids)	UPS / Backup Power Inverters
Use Scenario: Solid-state replacement for mechanical relays controlling HVAC actuators, industrial valves, or lighting ballasts. IC Role / Device Role / Timing Role: Unidirectional load switch handling inductive turn-off transients; operated with slow or zero-crossing gate timing. Use Value: Single-pulse avalanche energy rating (600 mJ) absorbs stored inductor energy without clamping circuits; 7.9 A I_D supports >10 A peak coil currents.	Use Scenario: DC-AC inversion stage in line-interactive UPS systems converting 24–48 VDC battery bank to 120/230 VAC output. IC Role / Device Role / Timing Role: Low-side switch in push-pull or full-bridge inverter; synchronized to SPWM carrier with dead-time control. Use Value: Low Q_g (68 nC) and fast switching (t_f = 24 ns) reduce switching losses at 20–50 kHz; R_thJC = 3.1 °C/W sustains continuous operation under battery discharge load.

Industrial AC/DC Power Supplies

Motor Drive Half-Bridge Legs

Use Scenario: Primary-side switch in 100–300 W offline flyback or forward converters operating from 85–265 VAC input.

IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer into transformer primary; operates at 65–130 kHz with hard switching.

Use Value: 250 V V_DS and 600 mJ E_AS provide margin for line surges and transformer leakage spikes; 0.28 Ω R_DS(on) limits conduction loss at full load.

Use Scenario: Upper or lower switch in 3-phase inverter stages for BLDC or stepper motor control up to 1 kW.

IC Role / Device Role / Timing Role: N-channel power switch in half-bridge topology; driven by isolated gate driver with bootstrap or transformer coupling.

Use Value: 4.8 V/ns dV/dt rating prevents spurious turn-on during high dv/dt cross-conduction; TO-220 FULLPAK isolation simplifies heatsink sharing across phases.

Inductive Load Switching (Relays/Solenoids)

UPS / Backup Power Inverters

Use Scenario: Solid-state replacement for mechanical relays controlling HVAC actuators, industrial valves, or lighting ballasts.

IC Role / Device Role / Timing Role: Unidirectional load switch handling inductive turn-off transients; operated with slow or zero-crossing gate timing.

Use Value: Single-pulse avalanche energy rating (600 mJ) absorbs stored inductor energy without clamping circuits; 7.9 A I_D supports >10 A peak coil currents.

Use Scenario: DC-AC inversion stage in line-interactive UPS systems converting 24–48 VDC battery bank to 120/230 VAC output.

IC Role / Device Role / Timing Role: Low-side switch in push-pull or full-bridge inverter; synchronized to SPWM carrier with dead-time control.

Use Value: Low Q_g (68 nC) and fast switching (t_f = 24 ns) reduce switching losses at 20–50 kHz; R_thJC = 3.1 °C/W sustains continuous operation under battery discharge load.

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel high-voltage power MOSFET applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP20NM50FP	500 V V_DS, 0.24 Ω R_DS(on), 70 nC Q_g, non-isolated TO-220FP	Lacks 2.5 kV isolation; requires external insulator for grounded heatsink use; higher voltage rating suits 400 VDC bus designs.	Select when higher V_DS margin is needed and isolation is handled externally; not drop-in for IRFI644G's insulated mounting.
FQP27P06	P-channel, -60 V V_DS, 0.055 Ω R_DS(on), 60 nC Q_g, non-isolated TO-220	Opposite channel type and polarity; unsuitable for high-side switching without level shift; lower voltage rating limits to low-voltage DC-DC.	Only viable in complementary low-side positions; incompatible for IRFI644G's high-voltage N-channel roles - requires circuit redesign.

Compared with STP20NM50FP and FQP27P06, the IRFI644G uniquely delivers integrated 2.5 kV isolation in a standard TO-220 footprint, enabling simplified, safer high-voltage switching without added insulation hardware - a capability neither alternative provides.

Availability

IRFI644G is available at Aetrix Electronics and suitable for industrial AC/DC power supplies, motor drive half-bridge legs, and inductive load switching requiring stable component supply, long-term lifecycle support, and certified isolation compliance.

Supply support for IRFI644G 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, ruggedness, and application-specific optimization.

The IRFI644G belongs to Vishay's high-voltage isolated power MOSFET product line, engineered for industrial switching applications demanding reinforced insulation, avalanche tolerance, and thermal efficiency in compact through-hole packages.

FAQ

What is the maximum continuous drain current for the IRFI644G at 100 °C case temperature?

The IRFI644G supports 5.0 A continuous drain current at T_C = 100 °C, derated from 7.9 A at 25 °C using a linear derating factor of 0.32 W/°C. This reflects thermal limitations of the TO-220 FULLPAK package and must be verified against actual heatsink performance and ambient conditions in the final design. The IRFI644G datasheet specifies this value in Absolute Maximum Ratings Table.

Does the IRFI644G require external insulation when mounted to a grounded heatsink?

No - the IRFI644G's TO-220 FULLPAK package provides 2.5 kV_RMS isolation between drain (tab) and leads, eliminating need for mica washers or insulating pads in most Class I industrial applications. Mounting torque must remain at 0.6 Nm for M3 screws to maintain integrity of the isolation barrier. The IRFI644G is explicitly designed for this insulated mounting configuration.

What is the gate-source threshold voltage range for the IRFI644G?

The IRFI644G has a gate-source threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V, measured at V_DS = V_GS and I_D = 250 μA. This allows reliable turn-on with standard 5 V or 10 V logic-level gate drivers, though full enhancement (R_DS(on) = 0.28 Ω) requires V_GS ≥ 10 V. The IRFI644G specification sheet confirms this range in the Static Characteristics table.

Can the IRFI644G be used in avalanche mode repeatedly?

The IRFI644G is rated for repetitive avalanche current (I_AR) of 7.9 A and repetitive avalanche energy (E_AR) of 4.0 mJ, but only under strictly limited pulse conditions (pulse width ≤ 300 μs, duty cycle ≤ 2 %). For sustained inductive switching, single-pulse avalanche (E_AS = 600 mJ) is guaranteed - repeated avalanche operation requires careful thermal and transient analysis. The IRFI644G datasheet defines these limits in Absolute Maximum Ratings.

What is the drain-to-sink capacitance of the IRFI644G and why does it matter?

The IRFI644G exhibits 12 pF drain-to-sink capacitance (C), measured at 1 MHz. This parameter directly impacts EMI generation and common-mode noise coupling in high-frequency switching applications - lower C reduces ground-loop currents and improves EMC performance in AC/DC converters and inverters. The IRFI644G's low 12 pF value is specified in the Dynamic Characteristics table of its official datasheet.

IRFI644G Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

Package/Case:: TO-220-3 Full Pack, Isolated Tab

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:: 7.9A (Tc)

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

Rds On (Max) @ Id, Vgs:: 280mOhm @ 4.7A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 68 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 1300 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 40W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

IRFI644G FAQ

1.How can I place an order for IRFI644G through Aetrix?

Please submit a Request for Quotation (RFQ) for IRFI644G 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 IRFI644G reliable?

The price and inventory of IRFI644G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRFI644G is usually 5 days.

3.What payment methods are accepted for IRFI644G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRFI644G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRFI644G?

IRFI644G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRFI644G 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 IRFI644G?

For technical support, including IRFI644G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRFI644G requirements.

6.How does Aetrix verify that IRFI644G is sourced from the original manufacturer or authorized distributors?

All IRFI644G 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 IRFI644G meets industry standards.

7.What is the process for return or replacement of IRFI644G?

All IRFI644G units undergo pre-shipment inspection (PSI). If there is an issue with IRFI644G, 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 IRFI644G part is unused and in its original packaging.

Return procedure for IRFI644G:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-11 Comparator Circuit: Voltage Thresholds, Op-Amp Differences, LM393 and Practical Design

Comparator circuit design covering voltage thresholds, input limits, open-collector outputs, LM393 wiring, op-amp differences, hysteresis, timing, window detection and practical fault diagnosis.

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 …