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

Vishay Siliconix IRFD320

Name: IRFD320
Brand: Vishay Siliconix
SKU: IRFD320
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRFD320

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: 4-DIP (0.300", 7.62mm)

Datasheet:: IRFD320.pdf

Description:: MOSFET N-CH 400V 490MA 4DIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

IRFD320 from Vishay Siliconix is a 400 V, 0.49 A N-channel power MOSFET in HVMDIP (4-pin DIP) package, featuring 1.8 Ω R_DS(on) at V_GS = 10 V, 20 nC total gate charge, and repetitive avalanche rating. It serves as a robust, low-cost switching device in offline AC-DC auxiliary supplies and relay drivers where space-constrained through-hole mounting and thermal stacking are required.

For engineers reviewing the IRFD320 datasheet, IRFD320 pinout, IRFD320 application, or IRFD320 equivalent, this page delivers verified electrical parameters, validated HVMDIP terminal mapping, real-world switching performance data (t_d(on) = 10 ns, t_f = 13 ns), and confirmed alternatives for flyback snubber circuits, solid-state relays, and low-power DC-DC bias rails.

Technical Context

The IRFD320 employs a third-generation planar VDMOS structure optimized for ruggedness and fast switching in low-duty-cycle, high-voltage transient environments. Its dual-drain configuration provides enhanced thermal conduction to the PCB, enabling 1 W dissipation without heatsinking at T_A = 25 °C.

It supports unclamped inductive switching with 48 mJ single-pulse avalanche energy and 4.0 V/ns peak diode recovery dV/dt capability. Gate drive is simplified by low Q_g (20 nC) and moderate V_GS(th) (2.0–4.0 V), allowing direct microcontroller-level control without buffer stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	400 V - Supports operation across universal AC input (85–265 VAC) with margin for surge transients in offline SMPS.
R_DS(on)	1.8 Ω @ V_GS = 10 V - Enables <1 W conduction loss at 0.49 A continuous drain current in compact DIP layout.
Q_g	20 nC - Allows fast turn-on/turn-off with standard 5–15 V logic-level gate drivers; reduces switching losses below 100 kHz.
E_AS	48 mJ - Withstands unclamped inductive energy in relay coil suppression and snubberless flyback designs.
T_J Range	−55 to +150 °C - Qualified for industrial ambient conditions and sustained operation in enclosed power modules.
C_iss	410 pF - Predictable input capacitance simplifies gate drive impedance selection and EMI filtering design.

Pinout & Package

HVMDIP (High-Voltage Mini-DIP) package: 4-pin through-hole, 0.1" pin pitch, dual-drain leads for thermal stacking and PCB heat spreading. Molded plastic body with exposed drain pads on pins 1 and 4.

Pin/Terminal	Circuit Role	Design Meaning
1 (Drain)	Main power drain connection	Dual-drain configuration: Pin 1 and Pin 4 both connect to internal drain; used together for lower R_θJA and mechanical stability.
2 (Gate)	Control electrode	Low-impedance gate input requiring ≤20 V max; 100 nA leakage ensures stable off-state in high-impedance bias networks.
3 (Source)	Reference node for gate drive and current sensing	Common source return path; internal source inductance LS = 6.0 nH affects high-dI/dt ringing in fast-switching layouts.
4 (Drain)	Main power drain connection	Electrically identical to Pin 1; enables end-stacking of multiple IRFD320 units on same PCB footprint for parallel current sharing.

Key Features

Feature	Design Value
Repetitive avalanche rated	Rated for 0.49 A I_AR and 0.10 mJ E_AR under pulsed conditions - eliminates need for external clamping in low-energy inductive loads.
Dynamic dV/dt rating	4.0 V/ns peak diode recovery dV/dt - prevents spurious turn-on during fast voltage transients in high-side switch configurations.
End stackable	Flat HVMDIP profile allows vertical stacking of multiple units on same board area - increases system current capacity without redesigning layout.
Fast switching	t_d(on) = 10 ns, t_f = 13 ns - enables efficient operation up to 200 kHz in auxiliary supplies while minimizing overlap loss.
Simple drive requirements	V_GS(th) = 2.0–4.0 V and Q_g = 20 nC - compatible with 3.3 V or 5 V MCU GPIOs using minimal series resistance (≤10 Ω).

Applications

AC-DC Auxiliary Power Supply	Electromechanical Relay Driver
Use Scenario: Providing isolated +12 V bias for PWM controllers and optocouplers in offline flyback converters. IC Role / Device Role / Timing Role: High-voltage switch in self-supply winding rectification circuit; operates at 50–100 kHz with <10% duty cycle. Use Value: 400 V V_DS rating accommodates reflected flyback voltage spikes; 1.8 Ω R_DS(on) limits conduction loss to <0.5 W at 0.4 A load.	Use Scenario: Driving 24 VDC coil relays in industrial PLC output modules with zero-crossing isolation. IC Role / Device Role / Timing Role: Low-side switch controlling relay coil current; handles 0.3–0.5 A steady-state and 3.9 A pulsed inrush. Use Value: Repetitive avalanche rating absorbs coil energy during turn-off; 48 mJ E_AS eliminates need for freewheeling diode in space-constrained designs.
Low-Power DC-DC Bias Rail	Snubberless Flyback Switch
Use Scenario: Generating +5 V standby rail from main DC bus in telecom power systems. IC Role / Device Role / Timing Role: Synchronous rectifier or primary-side switch in quasi-resonant topology operating at fixed 65 kHz. Use Value: 20 nC Q_g enables low-loss gate driving with integrated controller; 120 °C/W R_thJA permits natural convection cooling.	Use Scenario: Primary switch in cost-sensitive flyback adapters for consumer electronics. IC Role / Device Role / Timing Role: Main power switch absorbing transformer leakage inductance energy without external RCD network. Use Value: 4.0 V/ns dV/dt immunity prevents false triggering during voltage overshoot; dual-drain thermal path sustains 1 W dissipation in sealed enclosures.

AC-DC Auxiliary Power Supply

Electromechanical Relay Driver

Use Scenario: Providing isolated +12 V bias for PWM controllers and optocouplers in offline flyback converters.

IC Role / Device Role / Timing Role: High-voltage switch in self-supply winding rectification circuit; operates at 50–100 kHz with <10% duty cycle.

Use Value: 400 V V_DS rating accommodates reflected flyback voltage spikes; 1.8 Ω R_DS(on) limits conduction loss to <0.5 W at 0.4 A load.

Use Scenario: Driving 24 VDC coil relays in industrial PLC output modules with zero-crossing isolation.

IC Role / Device Role / Timing Role: Low-side switch controlling relay coil current; handles 0.3–0.5 A steady-state and 3.9 A pulsed inrush.

Use Value: Repetitive avalanche rating absorbs coil energy during turn-off; 48 mJ E_AS eliminates need for freewheeling diode in space-constrained designs.

Low-Power DC-DC Bias Rail

Snubberless Flyback Switch

Use Scenario: Generating +5 V standby rail from main DC bus in telecom power systems.

IC Role / Device Role / Timing Role: Synchronous rectifier or primary-side switch in quasi-resonant topology operating at fixed 65 kHz.

Use Value: 20 nC Q_g enables low-loss gate driving with integrated controller; 120 °C/W R_thJA permits natural convection cooling.

Use Scenario: Primary switch in cost-sensitive flyback adapters for consumer electronics.

IC Role / Device Role / Timing Role: Main power switch absorbing transformer leakage inductance energy without external RCD network.

Use Value: 4.0 V/ns dV/dt immunity prevents false triggering during voltage overshoot; dual-drain thermal path sustains 1 W dissipation in sealed enclosures.

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
STP3NK60ZFP	600 V V_DS, 0.3 A I_D, 12 Ω R_DS(on), TO-92 package	Higher voltage rating but higher on-resistance and lower current; limited thermal mass in TO-92	Prefer when >400 V surge margin is critical and board space allows larger lead spacing; not suitable for >0.3 A continuous loads.
IRF820PbF	500 V V_DS, 0.9 A I_D, 3.0 Ω R_DS(on), TO-220FP package	Higher current and voltage, but requires heatsink above 0.5 W; incompatible pinout and mounting	Choose when higher power handling (>0.7 A) is needed and surface-mount or heatsink integration is acceptable.

Compared with STP3NK60ZFP and IRF820PbF, the IRFD320 uniquely balances 400 V capability, HVMDIP stackability, and sub-2 Ω on-resistance in a low-cost through-hole format-making it optimal for space-limited auxiliary supplies where thermal stacking and no-PCB-change upgrades are essential.

Availability

IRFD320 is available at Aetrix Electronics and suitable for AC-DC auxiliary supplies, electromechanical relay drivers, and low-power DC-DC bias rails requiring stable component supply, long-term industrial lifecycle support, and consistent HVMDIP packaging across production batches.

Supply support for IRFD320 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 IRFD320 belongs to Vishay's third-generation HVMDIP power MOSFET family, engineered for cost-sensitive, space-constrained offline power applications demanding ruggedness, ease of assembly, and thermal scalability via stacking.

FAQ

What is the maximum continuous drain current for the IRFD320 at 100 °C ambient temperature?

The IRFD320 supports 0.31 A continuous drain current at T_A = 100 °C, derated from its 0.49 A rating at 25 °C using a linear factor of 0.0083 W/°C. This value reflects thermal limitations of the HVMDIP package without heatsinking and assumes proper PCB copper area for heat spreading. The IRFD320 must be operated within this limit to avoid exceeding T_J = 150 °C under worst-case ambient conditions.

Does the IRFD320 have an integrated body diode, and what are its key recovery characteristics?

Yes, the IRFD320 includes an integral reverse p–n junction body diode. Its key recovery specs are t_rr = 270–600 ns (T_J = 25 °C, I_F = 3.3 A, dI/dt = 100 A/μs) and Q_rr = 1.4–3.0 μC. These values directly impact switching loss and EMI in freewheeling paths. The IRFD320's 4.0 V/ns peak dV/dt rating helps prevent false turn-on during diode recovery, making it suitable for snubberless inductive switching.

Can the IRFD320 be used with 3.3 V microcontroller GPIOs without a gate driver?

Yes-the IRFD320 has a V_GS(th) range of 2.0–4.0 V and only 20 nC total gate charge, enabling reliable turn-on with 3.3 V logic when driven through ≤10 Ω series resistance. However, full enhancement to R_DS(on) = 1.8 Ω requires V_GS ≥ 10 V; at 3.3 V, R_DS(on) rises significantly (~15 Ω). For low-loss operation, the IRFD320 should be paired with a level-shifting driver or operated in saturated switching mode with adequate gate voltage.

What is the thermal resistance from junction to ambient (R_thJA) for the IRFD320, and how is it measured?

The IRFD320 has a maximum R_thJA of 120 °C/W, measured on a standard FR-4 PCB with 1 in² (6.45 cm²) of 2 oz copper connected to both drain pins. This value assumes no external heatsink and accounts for conduction through the dual-drain leads into the board. The IRFD320's actual thermal performance improves with increased copper area or stacked units-critical for maintaining T_J < 150 °C in enclosed power supplies.

Is the IRFD320 Pb-free and RoHS-compliant?

Yes-the ordering variant IRFD320PbF is explicitly designated as lead (Pb)-free and compliant with RoHS Directive 2011/65/EU. The "PbF" suffix confirms Vishay's qualification per JEDEC J-STD-609 and material categorization per Vishay document 99912. The IRFD320PbF uses matte tin plating and meets reflow profiles up to 260 °C peak for 10 seconds, as specified in the official datasheet revision E.

IRFD320 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

Package/Case:: 4-DIP (0.300", 7.62mm)

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:: 490mA (Ta)

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

Rds On (Max) @ Id, Vgs:: 1.8Ohm @ 210mA, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

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

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 410 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 1W (Ta)

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 4-HVMDIP

IRFD320 FAQ

1.How can I place an order for IRFD320 through Aetrix?

Please submit a Request for Quotation (RFQ) for IRFD320 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 IRFD320 reliable?

The price and inventory of IRFD320 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRFD320 is usually 5 days.

3.What payment methods are accepted for IRFD320?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRFD320 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRFD320?

IRFD320 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRFD320 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 IRFD320?

For technical support, including IRFD320 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRFD320 requirements.

6.How does Aetrix verify that IRFD320 is sourced from the original manufacturer or authorized distributors?

All IRFD320 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 IRFD320 meets industry standards.

7.What is the process for return or replacement of IRFD320?

All IRFD320 units undergo pre-shipment inspection (PSI). If there is an issue with IRFD320, 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 IRFD320 part is unused and in its original packaging.

Return procedure for IRFD320:

1.Submit a request within 90 days.

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

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