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

STMicroelectronics STU5N52K3

Name: STU5N52K3
Brand: STMicroelectronics
SKU: STU5N52K3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STU5N52K3

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

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

Datasheet:: STU5N52K3.pdf

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

Quantity:: RFQ Add To RFQ list

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Inventory:4,141

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Product details

Overview

STU5N52K3 from STMicroelectronics is an N-channel 525 V, 1.2 Ω (typ), 4.4 A SuperMESH3™ Power MOSFET in IPAK (TO-251) package, designed for high-voltage switching in offline SMPS, AC-DC adapters, and lighting ballasts where low conduction loss and robust avalanche capability are critical.

For engineers reviewing the STU5N52K3 datasheet, STU5N52K3 pinout, STU5N52K3 application, or STU5N52K3 equivalent, this device delivers verified 100% avalanche-tested ruggedness, 12 V/ns dv/dt immunity, Zener-protected gate, and optimized dynamic parameters including 17 nC total gate charge and 33 pF equivalent output capacitance for fast, reliable hard-switching operation.

Technical Context

This MOSFET employs ST's SuperMESH3™ vertical structure-enhanced over SuperMESH™-to achieve ultra-low R_DS(on) while maintaining high V_DSS and superior diode reverse recovery (t_rr = 210 ns at T_J = 25 °C). Its integrated gate-source Zener diodes clamp at 30 V to prevent overvoltage damage during transients.

The IPAK package provides 50 °C/W junction-to-ambient thermal resistance and supports 25 W total dissipation at T_C = 25 °C. It features a source-drain diode with 1.6 V forward voltage at 4.4 A and 1.3 µC reverse recovery charge, enabling efficient flyback and resonant converter topologies.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	525 V - Withstands full mains rectified voltage in universal-input 85–265 VAC systems without derating.
R_DS(on) max	1.5 Ω @ V_GS = 10 V, I_D = 2.2 A - Ensures <1.5 W conduction loss at 4.4 A, reducing heatsink requirements.
I_D cont @ T_C = 25 °C	4.4 A - Supports continuous output power up to ~100 W in flyback converters with adequate PCB copper area.
E_AS	100 mJ - Enables unclamped inductive switching without external snubbers in PFC and LLC stages.
Q_g	17 nC - Low gate drive energy reduces controller IC loading and enables use with standard 1-A gate drivers.
t_r/t_f	9 ns / 16 ns - Fast edge rates minimize switching transition losses in 65–130 kHz SMPS designs.
C_oss,eq	33 pF - Low effective output capacitance improves zero-voltage switching (ZVS) margin in resonant topologies.

Pinout & Package

STU5N52K3 uses the IPAK (TO-251) surface-mount package with 3 leads: Drain (D), Gate (G), Source (S). The exposed drain pad on the underside provides low-inductance, high-current path and thermal conduction to PCB copper.

Pin/Terminal	Circuit Role	Design Meaning
Lead 1 (G)	Gate	High-impedance control terminal; requires ≤±30 V drive; protected by integrated 30 V Zener diode.
Lead 2 (D)	Drain	Main high-voltage power terminal; connected to internal die backside; electrically tied to exposed metal pad.
Lead 3 (S)	Source	Power return and reference node; forms common connection for gate drive and current sensing.

Key Features

Feature	Design Value
100% avalanche tested	Guarantees single-pulse E_AS = 100 mJ at T_J = 25 °C, eliminating need for external avalanche protection circuits.
Zener-protected gate	Integrated dual back-to-back Zener diodes clamp V_GS to ±30 V, preventing gate oxide failure during ESD or layout-induced transients.
Extremely high dv/dt capability	Rated 12 V/ns - Suppresses false turn-on in high-noise environments like motor drives and industrial inverters.
Improved diode reverse recovery	t_rr = 210 ns, Q_rr = 1.3 µC - Reduces switching losses and EMI in discontinuous conduction mode (DCM) flyback converters.
Low intrinsic capacitance	C_iss = 545 pF, C_oss = 45 pF - Minimizes Miller effect and enables stable high-frequency operation up to 200 kHz.

Applications

Offline AC-DC Adapters

LED Driver Ballasts

Use Scenario: 12–24 W isolated flyback converter for universal-input (85–265 VAC) wall adapters powering consumer electronics.

IC Role / Device Role / Timing Role: Primary-side high-voltage switch operating at 65 kHz with DCM control; handles peak drain voltage up to 525 V.

Use Value: 1.2 Ω R_DS(on) and 17 nC Q_g reduce conduction and switching losses, enabling >85% efficiency without active cooling.

Use Scenario: Constant-current LED driver for street lighting using quasi-resonant flyback topology with 300–400 V DC bus.

IC Role / Device Role / Timing Role: Main power switch synchronized to valley-switching controller; withstands 420 V V_DD during ZVS transitions.

Use Value: 33 pF C_oss,eq and 210 ns t_rr improve ZVS soft-start reliability and lower EMI compared to legacy MOSFETs.

Industrial SMPS

Appliance Power Supplies

Use Scenario: 60 W open-frame power supply for PLC I/O modules, requiring high reliability under 4 kV surge conditions.

IC Role / Device Role / Timing Role: Primary-side switch in active-clamp forward converter; subjected to repetitive 100 V/ns dv/dt stress during clamping events.

Use Value: 12 V/ns dv/dt rating and 100% avalanche testing ensure no failure during line surges or transformer leakage spikes.

Use Scenario: Embedded power supply in washing machine main control board, converting 375 V DC bus to 12 V/5 V rails.

IC Role / Device Role / Timing Role: High-side switch in half-bridge configuration driving auxiliary transformer; operates at 100 kHz with 50% duty cycle.

Use Value: Integrated gate Zener eliminates need for external TVS, reducing BOM count and PCB footprint in space-constrained appliance designs.

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. IPAK's 5 °C/W; 70 W P_TOT vs. 25 W.	Better thermal performance in forced-air or heatsink-mounted setups; unsuitable for compact SMT-only layouts.	Select when higher power dissipation (>25 W) and mechanical mounting flexibility are required.
FQP5N50	500 V V_DSS, 1.5 Ω R_DS(on), no built-in Zener; 100% avalanche not specified; C_oss,eq = 55 pF.	Lacks gate protection and dv/dt immunity; requires external gate clamp; less robust in noisy industrial environments.	Choose only for cost-sensitive, non-safety-critical 230 VAC-only applications with controlled layout and low surge risk.

Compared with STU5N52K3, STP5N52K3 offers superior thermal handling but larger footprint, while FQP5N50 sacrifices ruggedness and gate protection for lower cost-making STU5N52K3 optimal for compact, high-reliability SMT SMPS where Zener protection and 525 V rating are mandatory.

Availability

STU5N52K3 is available at Aetrix Electronics and suitable for offline AC-DC adapters, LED driver ballasts, and industrial SMPS requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for STU5N52K3 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, specializing in power management, microcontrollers, and analog/mixed-signal ICs for industrial, automotive, and consumer markets.

STU5N52K3 belongs to the SuperMESH3™ Power MOSFET product line, engineered specifically for high-efficiency, high-reliability switching in universal-input offline power supplies and lighting systems.

FAQ

What is the maximum continuous drain current for STU5N52K3 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 IPAK package, which has R_thj-case = 5 °C/W and P_TOT = 25 W at T_C = 25 °C. Designers must ensure PCB copper area and ambient conditions maintain T_C ≤ 100 °C for sustained operation.

Does STU5N52K3 require an external gate resistor for safe operation?

Yes-a gate resistor is required to control dV/dt and prevent oscillation, though its value depends on drive strength and layout. The datasheet specifies switching times with R_G = 4.7 Ω (Table 6); typical design values range from 4.7 Ω to 22 Ω. Lower values increase switching speed but risk ringing; higher values reduce EMI but raise switching losses.

Can STU5N52K3 be used in synchronous rectification configurations?

No-STU5N52K3 is an N-channel high-side switch intended for primary-side switching, not secondary-side synchronous rectification. Its body diode is optimized for reverse recovery in flyback freewheeling, not low-V_F conduction. For synchronous rectification, ST recommends dedicated SR controllers paired with logic-level MOSFETs like STL10DN10LH.

Is the IPAK package of STU5N52K3 RoHS-compliant and lead-free?

Yes-STU5N52K3 is manufactured in ECOPACK®-compliant IPAK packages meeting RoHS Directive 2011/65/EU and REACH regulations. The device uses lead-free terminations and halogen-free molding compounds, with full compliance documentation available via ST's quality portal and distributor datasheets.

STU5N52K3 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: SuperMESH3™

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):: 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):: 70W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-251 (IPAK)

STU5N52K3 FAQ

1.How can I place an order for STU5N52K3 through Aetrix?

Please submit a Request for Quotation (RFQ) for STU5N52K3 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 STU5N52K3 reliable?

The price and inventory of STU5N52K3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STU5N52K3 is usually 5 days.

3.What payment methods are accepted for STU5N52K3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STU5N52K3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STU5N52K3?

STU5N52K3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STU5N52K3 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 STU5N52K3?

For technical support, including STU5N52K3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STU5N52K3 requirements.

6.How does Aetrix verify that STU5N52K3 is sourced from the original manufacturer or authorized distributors?

All STU5N52K3 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 STU5N52K3 meets industry standards.

7.What is the process for return or replacement of STU5N52K3?

All STU5N52K3 units undergo pre-shipment inspection (PSI). If there is an issue with STU5N52K3, 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 STU5N52K3 part is unused and in its original packaging.

Return procedure for STU5N52K3:

1.Submit a request within 90 days.

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

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