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

Vishay Siliconix IRFU320

Name: IRFU320
Brand: Vishay Siliconix
SKU: IRFU320
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRFU320

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: TO-251-3 Short Leads, IPAK, TO-251AA

Datasheet:: IRFU320.pdf

Description:: MOSFET N-CH 400V 3.1A TO251AA

Quantity:: RFQ Add To RFQ list

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Product details

Overview

IRFU320 from Vishay Siliconix is a 400 V, 3.1 A N-channel enhancement-mode power MOSFET in straight-lead IPAK (TO-251) package, optimized for through-hole mounting in high-voltage switching applications such as AC-DC adapters, offline SMPS, and motor control circuits. It features 1.8 Ω R_DS(on) at V_GS = 10 V, 20 nC total gate charge, and is rated for repetitive avalanche energy (4.2 mJ) and unclamped inductive switching.

For engineers reviewing the IRFU320 datasheet, IRFU320 pinout, IRFU320 application, or IRFU320 equivalent, this page delivers verified electrical specs, thermal derating behavior, body diode recovery characteristics (t_rr = 270–600 ns), PCB-mount power dissipation (2.5 W), and validated alternatives for high-voltage discrete switching design.

Technical Context

The IRFU320 employs third-generation trench-gate silicon technology to achieve low on-resistance while maintaining ruggedness against voltage transients and avalanche stress. Its gate threshold voltage (2.0–4.0 V) supports standard 10 V gate drive, and its dynamic dV/dt rating (4.0 V/ns) enables reliable operation in noisy high-side switching topologies.

Thermal performance is defined by R_thJC = 3.0 °C/W (junction-to-case) and R_thJA = 50 °C/W (junction-to-ambient, PCB mount), with linear derating of 0.020 W/°C above 25 °C ambient - critical for thermally constrained through-hole designs where heatsinking is limited to copper area on FR-4.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	400 V - supports primary-side switching in universal-input offline converters up to 265 V_AC with margin.
R_DS(on) @ V_GS = 10 V	1.8 Ω - determines conduction loss in continuous current paths; yields ~10.5 W max I²R loss at 3.1 A DC.
I_D (T_C = 25 °C)	3.1 A - maximum continuous drain current under ideal case cooling; derates to 2.0 A at 100 °C case temperature.
Q_g	20 nC - defines gate drive energy requirement; impacts switching loss and driver sizing for 100–500 kHz operation.
E_AS	160 mJ - single-pulse avalanche capability allows safe operation during inductive turn-off without snubbers in flyback or forward converters.
t_rr	270–600 ns - body diode reverse recovery time affects shoot-through risk and EMI in synchronous rectification or half-bridge configurations.
P_D (PCB mount)	2.5 W - maximum power dissipation on 1" square FR-4 board; sets practical DC/low-frequency load limits without external heatsink.

Pinout & Package

IRFU320 uses the IPAK (TO-251) straight-lead package, designed for through-hole mounting with internal drain-source-body diode integration. The package features a thermally enhanced exposed drain pad connected to lead 2, enabling direct PCB copper pour attachment for improved heat transfer.

Pin/Terminal	Circuit Role	Design Meaning
1 (G)	Gate	Controls channel conduction; requires ≥10 V drive for full enhancement; gate leakage < ±100 nA ensures low standby current.
2 (D)	Drain	High-voltage output node; internally connected to exposed thermal pad; must be routed over large copper area for thermal management.
3 (S)	Source	Reference node for gate drive and current sensing; body diode anode; ties to ground or low-side switch node in common configurations.

Key Features

Feature	Design Value
Repetitive avalanche rated	Enables robust operation under inductive load switching without external clamping; supports 3.1 A I_AR and 4.2 mJ E_AR per pulse.
Dynamic dV/dt rating	4.0 V/ns immunity prevents false turn-on during high dv/dt events in high-side or bridge configurations.
Fast switching	Turn-on delay 10 ns, rise time 14 ns, turn-off delay 30 ns, fall time 13 ns - reduces switching losses in 100–300 kHz SMPS.
Body diode with low V_SD	1.6 V forward drop at 3.1 A enables efficient freewheeling in flyback and buck-derived topologies without external diode.
Through-hole IPAK (TO-251)	Straight leads simplify manual assembly and rework; thermal pad allows >2× PCB heat spreading vs. standard TO-92.

Applications

AC-DC Adapter Primary Switch	Offline Flyback Converter
Use Scenario: 85–265 V_AC input, 12 V/2 A output adapter with primary-side regulation. IC Role / Device Role / Timing Role: High-voltage switching element in discontinuous conduction mode (DCM) flyback topology; handles 400 V blocking and 3.1 A peak current. Use Value: 1.8 Ω R_DS(on) minimizes conduction loss at light-to-moderate loads; avalanche rating eliminates need for TVS clamp during transformer reset.	Use Scenario: Universal-input industrial power supply with isolated 24 V/1.5 A output. IC Role / Device Role / Timing Role: Primary-side power switch operating at 65 kHz; subjected to 320 V V_DS spikes during demagnetization. Use Value: 4.2 mJ repetitive avalanche energy absorbs reset energy safely; 270 ns t_rr limits diode recovery loss and EMI generation.
DC Motor Drive Half-Bridge	LED Driver High-Side Switch
Use Scenario: 24 V brushed DC motor control with PWM at 20 kHz. IC Role / Device Role / Timing Role: Low-side switch in half-bridge configuration; commutates motor current with body diode freewheeling. Use Value: 3.1 A continuous current rating supports 15 W mechanical output; 1.6 V V_SD reduces freewheeling loss vs. external Schottky.	Use Scenario: Constant-current LED string driver with 350 V bus in streetlight application. IC Role / Device Role / Timing Role: High-side switch controlling LED current via source-follower gate drive. Use Value: 400 V V_DS withstands surge transients on outdoor lighting lines; 4.0 V/ns dV/dt rating prevents spurious turn-on during lightning-induced spikes.

AC-DC Adapter Primary Switch

Offline Flyback Converter

Use Scenario: 85–265 V_AC input, 12 V/2 A output adapter with primary-side regulation.

IC Role / Device Role / Timing Role: High-voltage switching element in discontinuous conduction mode (DCM) flyback topology; handles 400 V blocking and 3.1 A peak current.

Use Value: 1.8 Ω R_DS(on) minimizes conduction loss at light-to-moderate loads; avalanche rating eliminates need for TVS clamp during transformer reset.

Use Scenario: Universal-input industrial power supply with isolated 24 V/1.5 A output.

IC Role / Device Role / Timing Role: Primary-side power switch operating at 65 kHz; subjected to 320 V V_DS spikes during demagnetization.

Use Value: 4.2 mJ repetitive avalanche energy absorbs reset energy safely; 270 ns t_rr limits diode recovery loss and EMI generation.

DC Motor Drive Half-Bridge

LED Driver High-Side Switch

Use Scenario: 24 V brushed DC motor control with PWM at 20 kHz.

IC Role / Device Role / Timing Role: Low-side switch in half-bridge configuration; commutates motor current with body diode freewheeling.

Use Value: 3.1 A continuous current rating supports 15 W mechanical output; 1.6 V V_SD reduces freewheeling loss vs. external Schottky.

Use Scenario: Constant-current LED string driver with 350 V bus in streetlight application.

IC Role / Device Role / Timing Role: High-side switch controlling LED current via source-follower gate drive.

Use Value: 400 V V_DS withstands surge transients on outdoor lighting lines; 4.0 V/ns dV/dt rating prevents spurious turn-on during lightning-induced spikes.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
IRFR320	Same die, DPAK (TO-252) surface-mount package; R_thJA = 110 °C/W (vs. 50 °C/W for IRFU320 PCB mount); identical V_DS, R_DS(on), Q_g.	Requires reflow-compatible layout; unsuitable for manual prototyping or high-reliability through-hole assemblies.	Select IRFR320 only when automated SMT production and thermal constraints permit higher junction temperatures.
STP3NK80ZFP	800 V V_DS, 2.5 A I_D, 3.5 Ω R_DS(on); SuperMESH™ Zener-protected; no specified avalanche rating.	Better voltage margin but higher conduction loss; lacks documented repetitive avalanche capability for unclamped inductive loads.	Choose STP3NK80ZFP only when 800 V rating is mandatory and avalanche robustness is not required.

Compared with IRFU320, IRFR320 offers identical electrical performance but demands surface-mount assembly and exhibits worse thermal resistance on PCB; STP3NK80ZFP trades lower current and higher R_DS(on) for double the voltage rating but omits avalanche qualification - making IRFU320 the optimal choice for cost-sensitive, thermally constrained 400 V through-hole switching.

Availability

IRFU320 is available at Aetrix Electronics and suitable for AC-DC adapters, offline flyback converters, and DC motor drives requiring stable component supply across industrial and consumer electronics programs.

Supply support for IRFU320 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 power management and signal conditioning.

The IRFU320 belongs to Vishay's third-generation high-voltage power MOSFET family, engineered for ruggedness, fast switching, and cost-effective implementation in offline power conversion and motor control systems.

FAQ

What is the maximum continuous drain current for IRFU320 at 100 °C case temperature?

The IRFU320 supports 2.0 A continuous drain current at T_C = 100 °C, per its absolute maximum ratings table. This derating reflects thermal limitations of the IPAK (TO-251) package mounted on standard FR-4 PCB without forced air or heatsink. At 25 °C case temperature, the rating increases to 3.1 A. Designers must verify junction temperature using R_thJC = 3.0 °C/W and actual power dissipation to ensure T_J ≤ 150 °C.

Does IRFU320 have a qualified repetitive avalanche rating?

Yes, the IRFU320 is explicitly rated for repetitive avalanche operation: I_AR = 3.1 A and E_AR = 4.2 mJ, with pulse width limited by maximum junction temperature. This rating is confirmed in the Absolute Maximum Ratings table and supported by Figure 12c in the datasheet. It enables reliable unclamped inductive switching in flyback and forward converters without external snubbers.

What is the gate threshold voltage range for IRFU320?

The IRFU320 has a gate-source threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V at V_DS = V_GS and I_D = 250 μA. This range ensures compatibility with standard 5 V and 10 V logic-level gate drivers. Operation below 2.0 V guarantees device cutoff, while ≥10 V drive ensures full enhancement and minimal R_DS(on) - critical for minimizing conduction losses in high-efficiency designs.

How does the body diode performance of IRFU320 compare to external fast recovery diodes?

The IRFU320's integrated body diode has a forward voltage (V_SD) of 1.6 V at 3.1 A and reverse recovery time (t_rr) of 270–600 ns. While slower than dedicated ultrafast diodes (e.g., <100 ns), its V_SD is competitive with 1.5–1.8 V Schottkys. In low-frequency (<50 kHz) flyback or buck applications, it eliminates external diode count and cost; at higher frequencies, designers should evaluate EMI and recovery loss impact before omitting an external diode.

Can IRFU320 be used in place of IRFR320 in a design?

No - IRFU320 and IRFR320 share identical die characteristics but differ in package: IRFU320 uses straight-lead IPAK (TO-251) for through-hole mounting, while IRFR320 uses surface-mount DPAK (TO-252). Substitution requires PCB redesign, rework process changes, and thermal validation due to differing R_thJA (50 vs. 110 °C/W). They are not pin-compatible or drop-in replacements.

IRFU320 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

Package/Case:: TO-251-3 Short Leads, IPAK, TO-251AA

Packaging:: Tube

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 400 V

Current - Continuous Drain (Id) @ 25°C:: 3.1A (Tc)

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

Rds On (Max) @ Id, Vgs:: 1.8Ohm @ 1.9A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 20 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 350 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 2.5W (Ta), 42W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-251AA

IRFU320 FAQ

1.How can I place an order for IRFU320 through Aetrix?

Please submit a Request for Quotation (RFQ) for IRFU320 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 IRFU320 reliable?

The price and inventory of IRFU320 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRFU320 is usually 5 days.

3.What payment methods are accepted for IRFU320?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRFU320 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRFU320?

IRFU320 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRFU320 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 IRFU320?

For technical support, including IRFU320 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRFU320 requirements.

6.How does Aetrix verify that IRFU320 is sourced from the original manufacturer or authorized distributors?

All IRFU320 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 IRFU320 meets industry standards.

7.What is the process for return or replacement of IRFU320?

All IRFU320 units undergo pre-shipment inspection (PSI). If there is an issue with IRFU320, 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 IRFU320 part is unused and in its original packaging.

Return procedure for IRFU320:

1.Submit a request within 90 days.

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

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