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

STMicroelectronics STF5N52K3

Name: STF5N52K3
Brand: STMicroelectronics
SKU: STF5N52K3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STF5N52K3

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-220-3 Full Pack

Datasheet:: STF5N52K3.pdf

Description:: MOSFET N-CH 525V 4.4A TO220FP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

STF5N52K3 from STMicroelectronics is an N-channel 525 V, 1.2 Ω, 4.4 A SuperMESH3™ Power MOSFET in TO-220FP package, designed for high-voltage switching in offline SMPS, lighting ballasts, and AC-DC adapters. It features 100% avalanche tested ruggedness, 12 V/ns dv/dt capability, and integrated gate Zener protection at ±30 V.

For engineers reviewing the STF5N52K3 datasheet, STF5N52K3 pinout, STF5N52K3 application, or STF5N52K3 equivalent, key selection criteria include its 525 V V_DS, 1.2 Ω R_DS(on) at V_GS = 10 V, 25 W P_TOT, 17.6 A pulsed drain current, and Zener-protected gate structure - all critical for reliable high-voltage flyback and resonant converter designs.

Technical Context

This device uses ST's SuperMESH3™ vertical structure to achieve low on-resistance while maintaining high avalanche energy (100 mJ) and fast diode recovery (210 ns trr at T_J = 25 °C). Its gate charge profile (Q_g = 17 nC, Q_gd = 10 nC) supports efficient hard-switching up to 100 kHz.

The built-in back-to-back Zener diodes clamp gate-source voltage to ±30 V, eliminating external TVS requirements. Thermal resistance R_thj-case is 5.0 °C/W, enabling 25 W dissipation with modest heatsinking - a key differentiator versus standard TO-220FP MOSFETs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	525 V - Withstands full mains rectified voltage (e.g., 375 V DC + 30% surge) in universal-input offline converters.
R_DS(on) max	1.5 Ω at V_GS = 10 V, T_C = 25 °C - Enables <1.5 W conduction loss at 4.4 A continuous drain current.
I_D cont	4.4 A at T_C = 25 °C - Supports typical 20–30 W power supplies without forced air cooling.
E_AS	100 mJ - Absorbs unclamped inductive energy during overcurrent events without failure.
dv/dt	12 V/ns - Resists false turn-on in high-noise environments like motor drives and industrial inverters.
Q_g	17 nC - Reduces gate drive power and enables use with low-power controllers (e.g., VIPer, LNK series).
trr	210 ns at I_SD = 4.4 A, di/dt = 100 A/µs - Minimizes switching losses and EMI in quasi-resonant topologies.

Pinout & Package

STF5N52K3 is housed in a TO-220FP (Full-Pak) package: insulated plastic case with internal thermal pad, 3-pin single-ended configuration, and creepage/clearance optimized for high-voltage isolation. Mounting requires no insulating washer due to molded isolation between drain tab and mounting surface.

Pin/Terminal	Circuit Role	Design Meaning
1 (G)	Gate	High-impedance control input; Zener-protected to ±30 V - tolerates transient coupling without external clamping.
2 (D)	Drain	Main high-voltage power terminal; connected to internal die backside - electrically isolated from mounting surface in TO-220FP.
3 (S)	Source	Power return and reference node; ties to PCB ground plane; defines gate drive reference for low-side switching.

Key Features

Feature	Design Value
100% avalanche tested	Guarantees robustness under unclamped inductive switching - eliminates need for derating in flyback snubber design.
Extremely high dv/dt capability	12 V/ns rating prevents spurious turn-on during fast voltage transients in bridge-leg or half-bridge configurations.
Gate charge minimized	17 nC total gate charge reduces driver IC loading and improves efficiency in high-frequency SMPS (>65 kHz).
Zener-protected gate	Integrated ±30 V bidirectional Zener avoids external protection components - saves board space and BOM cost.
Improved diode reverse recovery	210 ns trr and 1.3 µC Q_rr reduce switching losses and EMI in quasi-resonant and LLC converters.

Applications

LED Driver

AC-DC Adapter

Use Scenario: Constant-current LED driver for commercial downlights using quasi-resonant flyback topology.

IC Role / Device Role / Timing Role: Primary-side high-voltage switch controlling energy transfer into output rectifier and filter.

Use Value: 525 V rating handles 277 VAC line surges; 1.2 Ω R_DS(on) keeps conduction loss below 2.5% at full load.

Use Scenario: Universal-input (90–264 VAC) 24 W laptop adapter with primary-side regulation.

IC Role / Device Role / Timing Role: Main power switch in discontinuous conduction mode (DCM) flyback converter.

Use Value: 100 mJ E_AS ensures safe operation during output short-circuit events without snubber redesign.

Industrial Control PSU

Electronic Ballast

Use Scenario: 24 V/2 A auxiliary power supply for PLC I/O modules operating in noisy factory environments.

IC Role / Device Role / Timing Role: High-side switch in active clamp forward converter for stable 24 V output.

Use Value: 12 V/ns dv/dt immunity prevents misfiring from EFT bursts per IEC 61000-4-4 Level 4.

Use Scenario: High-frequency electronic ballast for T5 fluorescent lamps (25–65 kHz operation).

IC Role / Device Role / Timing Role: Half-bridge switch driving resonant tank with soft-start and dimming control.

Use Value: Fast 210 ns diode recovery minimizes dead-time losses and enables precise zero-voltage switching (ZVS).

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP5N52K3	Same die, TO-220 package; R_thj-case = 1.79 °C/W vs. 5.0 °C/W; P_TOT = 70 W vs. 25 W.	Requires larger heatsink and mechanical isolation; suitable for higher-power designs (>40 W).	Select when thermal budget allows full TO-220 mounting and higher continuous power is needed.
FQP5N50	500 V V_DS, 1.5 Ω R_DS(on), no Zener gate protection, TO-220 package.	Lacks integrated gate clamping - mandates external 18 V Zener; lower voltage margin limits universal-input use.	Choose only for cost-sensitive, non-safety-critical 230 VAC-only applications with proven gate drive filtering.

Compared with STP5N52K3, STF5N52K3 trades 2.8× lower thermal resistance for 3.5× lower power rating - ideal for space-constrained, insulated-mount designs. Versus FQP5N50, it adds gate Zener protection and 25 V higher breakdown, enabling safer universal-input operation without added components.

Availability

STF5N52K3 is available at Aetrix Electronics and suitable for offline SMPS, LED drivers, and electronic ballasts requiring stable component supply across industrial and lighting OEM programs.

Supply support for STF5N52K3 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.

STF5N52K3 belongs to the SuperMESH3™ Power MOSFET product line, engineered specifically for high-efficiency, high-reliability switching in universal-input AC-DC conversion and lighting applications.

FAQ

What is the maximum continuous drain current for STF5N52K3 at 100 °C case temperature?

The maximum continuous drain current is 2.77 A at T_C = 100 °C, as specified in Table 2 of the datasheet. This derating reflects thermal limits of the TO-220FP package, where junction-to-case thermal resistance is 5.0 °C/W and maximum junction temperature is 150 °C.

Does STF5N52K3 require an external gate Zener diode?

No. STF5N52K3 integrates back-to-back Zener diodes between gate and source, rated for ±30 V breakdown (BVGSO), as confirmed in Table 8. This eliminates the need for external gate protection in standard flyback or forward converter designs.

How does the TO-220FP package differ from standard TO-220 in terms of mounting?

TO-220FP features full plastic insulation between the drain tab and mounting surface, allowing direct heatsink attachment without insulating washers. Standard TO-220 requires electrical isolation hardware, whereas TO-220FP simplifies assembly and improves thermal reliability in high-voltage systems.

Can STF5N52K3 be used in synchronous rectification applications?

No. STF5N52K3 is a single N-channel MOSFET with no complementary P-channel counterpart or logic-level gate drive optimization. Its 4.5 V maximum V_GS(th) and 10 V recommended V_GS make it unsuitable for low-voltage synchronous rectifier control where gate drive is derived from output winding voltage.

STF5N52K3 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: SuperMESH3™

Package/Case:: TO-220-3 Full Pack

Packaging:: Tube

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 525 V

Current - Continuous Drain (Id) @ 25°C:: 4.4A (Tc)

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

Rds On (Max) @ Id, Vgs:: 1.5Ohm @ 2.2A, 10V

Vgs(th) (Max) @ Id:: 4.5V @ 50µA

Gate Charge (Qg) (Max) @ Vgs:: 17 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 545 pF @ 100 V

FET Feature:: -

Power Dissipation (Max):: 25W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220FP

STF5N52K3 FAQ

1.How can I place an order for STF5N52K3 through Aetrix?

Please submit a Request for Quotation (RFQ) for STF5N52K3 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 STF5N52K3 reliable?

The price and inventory of STF5N52K3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STF5N52K3 is usually 5 days.

3.What payment methods are accepted for STF5N52K3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STF5N52K3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STF5N52K3?

STF5N52K3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STF5N52K3 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 STF5N52K3?

For technical support, including STF5N52K3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STF5N52K3 requirements.

6.How does Aetrix verify that STF5N52K3 is sourced from the original manufacturer or authorized distributors?

All STF5N52K3 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 STF5N52K3 meets industry standards.

7.What is the process for return or replacement of STF5N52K3?

All STF5N52K3 units undergo pre-shipment inspection (PSI). If there is an issue with STF5N52K3, 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 STF5N52K3 part is unused and in its original packaging.

Return procedure for STF5N52K3:

1.Submit a request within 90 days.

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

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