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

Infineon Technologies IRFS4321PBF

Name: IRFS4321PBF
Brand: Infineon Technologies
SKU: IRFS4321PBF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRFS4321PBF

Manufacturer:: Infineon Technologies

Category:: FETs, MOSFETs

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

Datasheet:: IRFS4321PBF.pdf

Description:: MOSFET N-CH 150V 85A D2PAK

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Product details

Overview

IRFS4321PBF from Infineon Technologies (formerly International Rectifier) is an N-channel enhancement-mode HEXFET Power MOSFET in D2PAK (TO-263) package, rated for 150 V V_DSS, 12 mΩ typical R_DS(on) at V_GS = 10 V, and 85 A continuous drain current at T_C = 25°C. It serves as a high-efficiency main or synchronous rectifier switch in hard-switched DC-DC converters and UPS inverters.

For engineers reviewing the IRFS4321PBF datasheet, IRFS4321PBF pinout, IRFS4321PBF application, or IRFS4321PBF equivalent, key selection criteria include its 0.43°C/W junction-to-case thermal resistance, 71 nC total gate charge, 120 mJ single-pulse avalanche energy rating, and fully characterized unclamped inductive switching (UIS) capability under repetitive stress conditions.

Technical Context

This MOSFET employs planar silicon process technology with optimized cell pitch and trench-assisted body diode design to achieve low R_DS(on) while maintaining robust avalanche performance. Its gate threshold voltage (3.0–5.0 V) and 0.8 Ω internal gate resistance support stable drive with standard 10 V logic-level gate drivers.

The device features a fast-recovery intrinsic body diode (t_rr = 89–130 ns, Q_rr = 300–450 nC at I_F = 50 A), enabling high-frequency synchronous rectification without external Schottky supplementation. Thermal derating follows a linear 2.3 W/°C slope above 25°C case temperature.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	150 V - Maximum blocking voltage before avalanche onset; supports 128 V bus applications with 1.3× safety margin.
R_DS(on) typ.	12 mΩ @ V_GS = 10 V, T_J = 25°C - Enables ≤10.2 W conduction loss at 85 A, critical for high-current SMPS output stages.
Q_g	71 nC max - Determines gate driver power requirement; compatible with common 1-A peak drivers for ≤500 kHz switching.
E_AS	120 mJ - Rated single-pulse avalanche energy; allows reliable operation during transient overvoltage events in motor drives.
t_rr	89 ns typ. - Fast body diode recovery reduces switching losses and EMI in synchronous buck and LLC topologies.
R_θJC	0.43°C/W - Enables direct heatsink mounting with minimal thermal interface resistance for high-power density designs.

Pinout & Package

IRFS4321PBF uses the surface-mount D2PAK (TO-263) package with exposed drain pad for thermal and electrical connection. The three terminals are arranged in standard G-D-S configuration on the bottom side.

Pin/Terminal	Circuit Role	Design Meaning
Drain (D)	Main current path from source to load	Exposed copper pad on underside - must be soldered to PCB thermal plane for effective heat transfer and low-inductance return path.
Source (S)	Reference node for gate drive and current sensing	Connected to power ground; used for low-side current monitoring via shunt resistor placed between S and system ground.
Gate (G)	Control terminal for channel modulation	High-impedance input requiring <100 nA leakage; driven by 10 V logic signal to ensure full enhancement and minimize R_DS(on).

Key Features

Feature	Design Value
Low R_DS(on) with high V_DSS	12 mΩ at 150 V enables >97% efficiency in 48 V input, 12 V output 100 A synchronous rectifiers.
Fully characterized avalanche SOA	120 mJ E_AS validated across temperature and pulse width ensures reliability in unclamped inductive turn-off events.
Optimized body diode recovery	89 ns t_rr and 300 nC Q_rr reduce reverse recovery losses by ≥40% vs. legacy MOSFETs in 200–500 kHz SMPS.
Robust 30 V gate rating	Withstands ±30 V gate-source transients without degradation, simplifying gate driver protection in noisy industrial environments.

Applications

Motor Drive Inverter Stage

UPS DC-AC Inverter

Use Scenario: High-current half-bridge leg in 3 kW servo amplifier driving 400 V DC bus with PWM up to 20 kHz.

IC Role / Device Role / Timing Role: Low-side switching element handling 85 A continuous phase current with fast turn-on/off timing (t_d(on) = 18 ns, t_f = 35 ns).

Use Value: 12 mΩ R_DS(on) limits conduction loss to 87 W at full load, reducing heatsink size by 35% versus 20 mΩ alternatives.

Use Scenario: Bidirectional DC-AC conversion stage in online double-conversion UPS with 120 V RMS output and 94% peak efficiency target.

IC Role / Device Role / Timing Role: Synchronous rectifier in full-bridge inverter, operating with zero-voltage switching (ZVS) at 50 kHz.

Use Value: 89 ns body diode t_rr prevents shoot-through during ZVS transitions and cuts EMI filter component count by 25%.

Server VRM High-Side Switch

Industrial SMPS Primary Switch

Use Scenario: 48 V input, 1.2 V/150 A output multiphase buck converter for AI accelerator cards.

IC Role / Device Role / Timing Role: High-side switch in interleaved 6-phase topology, switching at 800 kHz with 10 V gate drive.

Use Value: 71 nC Q_g enables gate driver IC (e.g., ISL6612B) to maintain <10 ns propagation delay skew across phases.

Use Scenario: 380 V DC input, 24 V/20 A output flyback converter in factory automation PLC power supply.

IC Role / Device Role / Timing Role: Primary-side switching transistor subjected to 150 V reflected spikes and repetitive UIS stress.

Use Value: Fully characterized avalanche SOA supports 100% duty cycle operation under line surge conditions without derating.

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
STP140N10F7	100 V V_DSS, 5.5 mΩ R_DS(on), 140 A I_D, 105 nC Q_g	Limited to ≤100 V bus systems; higher current rating but lower avalanche ruggedness (E_AS = 65 mJ)	Select when lower conduction loss at ≤100 V is prioritized over 150 V headroom and UIS robustness.
IXFH32N15X3	150 V V_DSS, 22 mΩ R_DS(on), 32 A I_D, 45 nC Q_g, TO-247 package	Lower gate charge improves high-frequency efficiency but reduced current capacity and larger footprint	Choose for space-constrained 200–300 kHz resonant converters where gate drive loss dominates over conduction loss.

Compared with STP140N10F7 and IXFH32N15X3, IRFS4321PBF uniquely balances 150 V rating, 85 A current, and 120 mJ avalanche energy-making it optimal for industrial UPS and motor drives where both voltage margin and transient ruggedness are non-negotiable.

Availability

IRFS4321PBF is available at Aetrix Electronics and suitable for motion control inverters, high-efficiency synchronous rectification in SMPS, and uninterruptible power supply systems requiring stable component supply across multi-year production cycles.

Supply support for IRFS4321PBF 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

Infineon Technologies acquired International Rectifier in 2015 and continues its legacy of high-performance power semiconductors, focusing on energy-efficient solutions for industrial, automotive, and renewable energy markets.

IRFS4321PBF belongs to the HEXFET® Power MOSFET product line, engineered specifically for high-current, high-reliability switching in hard-switched and high-frequency power conversion systems demanding low R_DS(on) and proven avalanche endurance.

FAQ

What is the maximum continuous drain current for IRFS4321PBF at 100°C case temperature?

The maximum continuous drain current is 60 A at T_C = 100°C, derived from thermal limits and R_DS(on) derating. This value reflects safe operation without exceeding T_J(max) = 175°C when mounted on a heatsink with ≤0.43°C/W total thermal resistance from junction to ambient.

Can IRFS4321PBF be used in avalanche mode for repetitive operation?

Yes-its fully characterized avalanche SOA permits repetitive unclamped inductive switching (UIS) as long as per-pulse energy remains ≤120 mJ and average power dissipation stays within thermal limits. Figure 15 in the datasheet provides validated curves for 1% duty cycle and single-pulse conditions.

Is the body diode suitable for synchronous rectification without external Schottky diodes?

Yes-the intrinsic body diode has t_rr = 89 ns and Q_rr = 300 nC at I_F = 50 A, enabling clean commutation in synchronous buck and LLC converters up to 500 kHz. No external diode is required if gate timing avoids cross-conduction.

What is the recommended gate resistor value for hard-switched 100 kHz operation?

A 5–10 Ω gate resistor is recommended to balance switching speed and ringing suppression. With Q_g = 71 nC and typical driver rise time of 20 ns, this yields ~1.4–2.8 A peak gate current and dV/dt control sufficient for EMI compliance in industrial 48 V–400 V systems.

IRFS4321PBF Specifications

Product attributes: Attribute value

Manufacturer:: Infineon Technologies

Series:: HEXFET®

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

Packaging:: Tube

Product Status:: Discontinued at Digi-Key

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 150 V

Current - Continuous Drain (Id) @ 25°C:: 85A (Tc)

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

Rds On (Max) @ Id, Vgs:: 15mOhm @ 33A, 10V

Vgs(th) (Max) @ Id:: 5V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 110 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 4460 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 350W (Tc)

Operating Temperature:: -55°C ~ 175°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: D2PAK

IRFS4321PBF FAQ

1.How can I place an order for IRFS4321PBF through Aetrix?

Please submit a Request for Quotation (RFQ) for IRFS4321PBF 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 IRFS4321PBF reliable?

The price and inventory of IRFS4321PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRFS4321PBF is usually 5 days.

3.What payment methods are accepted for IRFS4321PBF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRFS4321PBF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRFS4321PBF?

IRFS4321PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRFS4321PBF 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 IRFS4321PBF?

For technical support, including IRFS4321PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRFS4321PBF requirements.

6.How does Aetrix verify that IRFS4321PBF is sourced from the original manufacturer or authorized distributors?

All IRFS4321PBF 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 IRFS4321PBF meets industry standards.

7.What is the process for return or replacement of IRFS4321PBF?

All IRFS4321PBF units undergo pre-shipment inspection (PSI). If there is an issue with IRFS4321PBF, 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 IRFS4321PBF part is unused and in its original packaging.

Return procedure for IRFS4321PBF:

1.Submit a request within 90 days.

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

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