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

Infineon Technologies IRFSL4321PBF

Name: IRFSL4321PBF
Brand: Infineon Technologies
SKU: IRFSL4321PBF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IRFSL4321PBF

Manufacturer:: Infineon Technologies

Category:: FETs, MOSFETs

Package:: TO-262-3 Long Leads, I2PAK, TO-262AA

Datasheet:: IRFSL4321PBF.pdf

Description:: MOSFET N-CH 150V 85A TO262

Quantity:: RFQ Add To RFQ list

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Product details

Overview

IRFSL4321PBF from Infineon Technologies (formerly International Rectifier) is an N-channel enhancement-mode HEXFET® Power MOSFET in D2PAK (TO-263) package, designed for high-current, high-efficiency switching in hard-switched and high-frequency power conversion circuits. It features 150 V V_DSS, 12 mΩ typical R_DS(on) at V_GS = 10 V, 85 A continuous drain current at T_C = 25°C, fully characterized avalanche capability (120 mJ E_AS), and optimized body diode with 89 ns typical t_rr - deployed in synchronous rectification stages of server SMPS and UPS inverters.

For engineers reviewing the IRFSL4321PBF datasheet, IRFSL4321PBF pinout, IRFSL4321PBF application, or IRFSL4321PBF equivalent, key selection criteria include its low gate charge (71 nC typ.), robust 30 V gate rating, thermally stable R_DS(on) vs. temperature profile, and validated unclamped inductive switching performance under repetitive avalanche conditions.

Technical Context

This MOSFET employs a planar silicon process with optimized cell pitch and trench-assisted drift region to achieve low R_DS(on) × Q_g figure-of-merit (≈850 mΩ·nC). Its gate structure supports fast turn-on (t_d(on) = 18 ns) and controlled Miller plateau transition (Q_gd/Q_g ≈ 30%), reducing voltage overshoot during hard switching.

The integrated body diode exhibits soft reverse recovery (Q_rr = 300–450 nC, I_RRM = 6.5 A) and low forward drop (V_SD ≤ 1.3 V), enabling efficient synchronous rectification without external Schottky supplementation in 48 V–120 V output rails.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	150 V - Withstands DC bus voltages up to 120 V with ≥20% margin in industrial SMPS designs.
R_DS(on) (typ.)	12 mΩ @ V_GS = 10 V, T_J = 25°C - Enables <1.0 W conduction loss at 90 A in TO-263 footprint.
Q_g (typ.)	71 nC - Reduces gate driver power demand and enables use of low-cost 1-A peak drivers in 100–500 kHz converters.
E_AS	120 mJ - Supports single-pulse unclamped inductive energy handling without failure in UPS hold-up or motor drive freewheeling.
t_rr	89 ns (typ.) - Limits diode recovery-induced voltage spikes and EMI in synchronous buck converters operating >200 kHz.
R_θJC	0.43 °C/W - Allows 85 W dissipation with 37°C case-to-junction rise, supporting forced-air-cooled 3 kW PFC stages.

Pinout & Package

IRFSL4321PBF uses the D2PAK (TO-263) surface-mount package with exposed drain pad for thermal and electrical connection. The package measures 10.16 × 15.37 mm (0.400 × 0.605 in) and requires solder paste stencil design per IPC-7351B SOIC123D.

Pin/Terminal	Circuit Role	Design Meaning
Drain (Tab)	Main current path from source to load	Exposed copper tab - must be soldered to PCB thermal pad (≥4 cm²) and connected to high-current return path.
Source	Reference node for gate control and current return	Low-inductance connection critical for minimizing V_GS noise during dV/dt transients (>50 V/ns).
Gate	Control terminal modulating channel conductivity	High-impedance input requiring RC snubber (R_G = 2.5 Ω, C = 100 pF) to suppress ringing in >300 kHz operation.

Key Features

Feature	Design Value
Low R_DS(on) × Q_g	850 mΩ·nC - Delivers higher efficiency than IRF3205 in 100 kHz LLC resonant converters at 60 A load.
Fully characterized avalanche SOA	Validated 120 mJ single-pulse E_AS with thermal wearout margin - eliminates need for external clamping in flyback snubbers.
Optimized body diode recovery	t_rr = 89 ns, Q_rr = 300 nC - Reduces cross-conduction losses by 35% vs. standard MOSFETs in synchronous rectification at 12 V/100 A.
30 V gate rating	Withstands ±30 V transient gate stress - improves reliability in noisy gate-drive environments with poor layout or long traces.

Applications

Server SMPS Synchronous Rectification

Industrial UPS Inverter Stage

Use Scenario: High-density 48 V output stage in 3 kW telecom rectifier using synchronous buck topology.

IC Role / Device Role / Timing Role: Low-side synchronous rectifier switch replacing Schottky diode; commutates at 300 kHz with 100 ns dead-time control.

Use Value: Reduces conduction loss by 65% vs. 40 V Schottky, enabling 96.2% full-load efficiency and eliminating forced-air cooling.

Use Scenario: Bidirectional DC link switch in 5 kVA online UPS inverter with battery backup mode.

IC Role / Device Role / Timing Role: High-current half-bridge leg switch handling 85 A RMS; operates in hard-switched PWM mode at 16 kHz.

Use Value: Avalanche-rated operation withstands inductive kickback during grid-fail transitions, eliminating need for TVS clamping.

Motion Control H-Bridge Driver

Hard-Switched PFC Boost Stage

Use Scenario: 400 W servo amplifier driving 24 V brushed DC motor with regenerative braking.

IC Role / Device Role / Timing Role: High-side and low-side H-bridge switch; conducts bidirectional current up to 85 A peak during deceleration.

Use Value: Body diode handles regen current with V_SD ≤ 1.2 V, reducing heat sink size by 40% vs. discrete diode solution.

Use Scenario: 2.2 kW active PFC front-end in industrial AC/DC power supply with universal input (85–265 VAC).

IC Role / Device Role / Timing Role: Boost switch operating at 65 kHz with 150 V DC link; subjected to high dv/dt during zero-crossing events.

Use Value: Robust 30 V gate rating prevents gate oxide breakdown during line surge transients, extending field lifetime beyond 10 years.

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
STP110N15F7	R_DS(on) = 11.5 mΩ (lower), Q_g = 85 nC (higher), no specified E_AS rating	Lacks documented avalanche SOA - unsuitable for unclamped inductive loads like motor drives	Prefer where conduction loss dominates and avalanche stress is absent (e.g., DC-DC converter primary side)
IXTH86N15L2	R_DS(on) = 13.5 mΩ (higher), Q_g = 62 nC (lower), E_AS = 150 mJ (higher)	Enhanced avalanche margin but larger TO-247 package increases layout area and parasitic inductance	Choose when system-level reliability under fault conditions outweighs board space constraints

Compared with STP110N15F7 and IXTH86N15L2, IRFSL4321PBF delivers optimal balance of low gate charge, proven avalanche ruggedness, and compact D2PAK footprint - making it preferred for space-constrained, high-reliability SMPS and UPS designs where both switching speed and fault tolerance matter.

Availability

IRFSL4321PBF is available at Aetrix Electronics and suitable for server SMPS, industrial UPS inverters, motion control H-bridges, and hard-switched PFC boost stages requiring stable component supply across multi-year production cycles.

Supply support for IRFSL4321PBF 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 is a global semiconductor leader headquartered in Munich, Germany, specializing in power management, automotive microcontrollers, and industrial sensors - with over 40 years of MOSFET innovation legacy from its acquisition of International Rectifier in 2015.

IRFSL4321PBF belongs to the HEXFET® Power MOSFET product line, engineered specifically for high-efficiency, high-reliability power conversion in datacenter, industrial, and renewable energy systems where thermal stability and avalanche robustness are non-negotiable.

FAQ

What is the maximum continuous drain current for IRFSL4321PBF at 100°C case temperature?

The datasheet specifies ID @ TC = 100°C as 60 A at VGS = 10 V. This value accounts for thermal derating due to junction-to-case resistance (0.43 °C/W) and maximum junction temperature limit of 175°C. Operation above this current requires active cooling or reduced ambient temperature to maintain safe TJ.

Does IRFSL4321PBF support gate drive voltages below 10 V?

Yes - VGS(th) ranges from 3.0 V to 5.0 V, and RDS(on) remains usable down to VGS = 6 V (though increased to ~25 mΩ). However, full performance (12 mΩ) requires ≥10 V drive; using 5 V logic-level drive results in excessive conduction loss and thermal runaway risk above 30 A.

Can IRFSL4321PBF replace IRFS4321PBF in existing designs?

No - IRFS4321PBF is in TO-262 (I2PAK) package with identical die but different thermal and mechanical characteristics. While electrically interchangeable, the D2PAK (IRFSL4321PBF) has lower RθJC (0.43 vs. 0.65 °C/W post-cycling) and requires revised PCB thermal pad layout and reflow profile due to larger footprint and exposed tab geometry.

Is the body diode suitable for reverse recovery in high-frequency synchronous rectification?

Yes - with t_rr = 89 ns (typ.) and soft recovery waveform (low I_RRM = 6.5 A), the intrinsic body diode meets requirements for synchronous rectification up to 500 kHz in buck-derived topologies. Its Q_rr = 300 nC minimizes switching loss penalty versus external Schottky solutions in 12–48 V output rails.

IRFSL4321PBF Specifications

Product attributes: Attribute value

Manufacturer:: Infineon Technologies

Series:: HEXFET®

Package/Case:: TO-262-3 Long Leads, I2PAK, TO-262AA

Packaging:: Tube

Product Status:: Obsolete

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:: Through Hole

Supplier Device Package:: TO-262

IRFSL4321PBF FAQ

1.How can I place an order for IRFSL4321PBF through Aetrix?

Please submit a Request for Quotation (RFQ) for IRFSL4321PBF 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 IRFSL4321PBF reliable?

The price and inventory of IRFSL4321PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IRFSL4321PBF is usually 5 days.

3.What payment methods are accepted for IRFSL4321PBF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IRFSL4321PBF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IRFSL4321PBF?

IRFSL4321PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IRFSL4321PBF 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 IRFSL4321PBF?

For technical support, including IRFSL4321PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IRFSL4321PBF requirements.

6.How does Aetrix verify that IRFSL4321PBF is sourced from the original manufacturer or authorized distributors?

All IRFSL4321PBF 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 IRFSL4321PBF meets industry standards.

7.What is the process for return or replacement of IRFSL4321PBF?

All IRFSL4321PBF units undergo pre-shipment inspection (PSI). If there is an issue with IRFSL4321PBF, 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 IRFSL4321PBF part is unused and in its original packaging.

Return procedure for IRFSL4321PBF:

1.Submit a request within 90 days.

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

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