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

STMicroelectronics STQ3N45K3-AP

Name: STQ3N45K3-AP
Brand: STMicroelectronics
SKU: STQ3N45K3-AP
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STQ3N45K3-AP

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: STQ3N45K3-AP.pdf

Description:: MOSFET N-CH 450V 600MA TO92-3

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Product details

Overview

STQ3N45K3-AP from STMicroelectronics is an N-channel 450 V, 3.3 Ω typ. R_DS(on), 0.6 A Zener-protected SuperMESH3™ Power MOSFET in TO-92 package, designed for low-power switching in AC/DC adapters and LED drivers where high dv/dt immunity and integrated gate protection are critical.

For engineers reviewing the STQ3N45K3-AP datasheet, STQ3N45K3-AP pinout, STQ3N45K3-AP application, or STQ3N45K3-AP equivalent, key selection criteria include its 450 V V_DSS, 12 V/ns dv/dt rating, 1000 V HBM ESD tolerance, Zener-protected gate, and 3 W power dissipation at T_C = 25 °C.

Technical Context

This device implements a vertically optimized SuperMESH3™ structure with minimized gate charge (9.5 nC typical) and ultra-low intrinsic capacitance (C_iss = 164 pF, C_oss = 17 pF), enabling fast switching (t_d(on) = 6.5 ns, t_f = 22 ns) while maintaining robust unclamped inductive switching capability (E_AS = 45 mJ).

The integrated back-to-back gate-source Zener diodes provide 30 V breakdown protection (V_(BR)GSO) and eliminate external clamping components; its source-drain diode features improved reverse recovery (t_rr = 175 ns, Q_rr = 550 nC) and low forward voltage (V_SD = 1.5 V at 0.6 A).

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	450 V - Withstands mains-referenced drain voltages in universal-input offline converters.
R_DS(on) typ.	3.3 Ω @ V_GS = 10 V, I_D = 0.6 A - Enables low conduction loss in sub-1 W auxiliary supplies.
Q_g	9.5 nC - Reduces gate drive power and enables efficient operation with low-cost controllers.
dv/dt	12 V/ns - Resists false triggering in noisy high-voltage environments without snubbers.
E_AS	45 mJ - Sustains repetitive avalanche energy during inductive turn-off transients.
V_(BR)GSO	30 V - Integrated Zener clamps gate to source, removing need for external TVS diodes.
P_TOT	3 W @ T_C = 25 °C - Defines thermal limit for PCB-mounted TO-92 operation with minimal copper area.

Pinout & Package

TO-92 package (Ammopak), through-hole mounting, 3-pin configuration with standard lead assignment: Pin 1 = Gate, Pin 2 = Drain, Pin 3 = Source.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Gate	Control terminal; accepts 10 V logic-level drive; protected by internal 30 V Zener diode.
Pin 2	Drain	High-voltage output node; rated for 450 V DC blocking and 2.4 A pulsed current.
Pin 3	Source	Power return path and reference for gate drive; connected to PCB ground plane for thermal and EMI control.

Key Features

Feature	Design Value
100% avalanche tested	Guarantees single-pulse E_AS = 45 mJ performance across production lot-no derating needed for flyback snubberless designs.
Extremely high dv/dt capability	12 V/ns rating prevents spurious turn-on during rapid voltage transients in high-side switch configurations.
Minimized gate charge	9.5 nC total gate charge reduces driver losses and allows use of low-power gate drivers like STM32 GPIOs.
Zener-protected gate	Integrated 30 V bidirectional Zener eliminates external gate clamp, reducing BOM count and board space in cost-sensitive adapters.
Improved diode reverse recovery	t_rr = 175 ns and Q_rr = 550 nC minimize switching loss and EMI in discontinuous conduction mode (DCM) flybacks.

Applications

AC/DC Auxiliary Power Supply

LED Driver for Mains-Powered Luminaires

Use Scenario: Provides isolated 12 V bias supply for PWM controllers in 5–15 W offline SMPS.

IC Role / Device Role / Timing Role: Primary-side high-voltage switch in DCM flyback topology operating at 65–100 kHz.

Use Value: Low R_DS(on) and fast t_f reduce conduction and switching losses; Zener protection ensures reliability under line surge conditions.

Use Scenario: Drives constant-current LED strings in retrofit GU10 and E27 lamps with universal AC input.

IC Role / Device Role / Timing Role: High-side switch in buck-derived primary-side regulated topology.

Use Value: 450 V V_DSS supports direct rectified mains operation; low Q_g enables stable dimming down to 1% without flicker.

Smart Home Sensor Node Power

Industrial Control Signal Isolation

Use Scenario: Powers low-duty-cycle wireless sensor modules (Zigbee/Z-Wave) from 230 V AC via capacitive dropper + linear regulator.

IC Role / Device Role / Timing Role: Series pass switch regulating peak current into bulk capacitor.

Use Value: 1000 V HBM ESD rating ensures robustness during automated assembly; TO-92 footprint simplifies manual rework.

Use Scenario: Isolates 24 V DC control signals in PLC I/O modules using optocoupler-driven gate drive.

IC Role / Device Role / Timing Role: Fast-switching interface between microcontroller and relay coil or solenoid load.

Use Value: 2.4 A pulsed ID capability handles inductive kickback; 12 V/ns dv/dt immunity prevents misfiring in electrically noisy cabinets.

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel 450 V power MOSFET applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP3NK45Z	Same V_DSS (450 V), higher R_DS(on) (4.5 Ω typ.), no integrated Zener, TO-220 package	Requires external gate protection; better suited for heatsinked >5 W designs	Select when higher power handling and thermal margin outweigh board space and BOM simplicity.
FQP3N45	450 V V_DSS, 4.2 Ω R_DS(on), no Zener, TO-220FP package, lower Q_g (7.5 nC)	Lacks avalanche rating and gate protection; not 100% avalanche tested	Choose only for non-safety-critical, low-cost consumer applications with clean supply rails.

Compared with STP3NK45Z and FQP3N45, the STQ3N45K3-AP uniquely combines Zener-protected gate, TO-92 compactness, and guaranteed avalanche ruggedness-making it optimal for space-constrained, surge-prone auxiliary supplies where reliability trumps raw power density.

Availability

STQ3N45K3-AP is available at Aetrix Electronics and suitable for AC/DC auxiliary power supplies, LED drivers for mains-powered luminaires, and smart home sensor node power requiring stable component supply across long-lifecycle industrial and lighting programs.

Supply support for STQ3N45K3-AP 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, MCU, power, and sensor solutions for automotive, industrial, and consumer markets.

This device belongs to ST's SuperMESH3™ Power MOSFET product line, engineered specifically for high-voltage, low-power switching applications demanding ruggedness, compact packaging, and integrated protection-especially in cost-sensitive offline power conversion.

FAQ

What is the maximum continuous drain current for STQ3N45K3-AP at 100 °C case temperature?

At T_C = 100 °C, the maximum continuous drain current is derated to approximately 0.35 A based on the R_thj-case = 42 °C/W thermal resistance and T_j(max) = 150 °C limit. This reflects real-world thermal constraints in sealed enclosures without forced airflow.

Can STQ3N45K3-AP be used in linear regulation mode?

No-it is not characterized or rated for linear (ohmic) operation. Its Safe Operating Area (SOA) curve shows limited DC capability beyond 10 µs pulses, and sustained operation above 0.6 A at V_DS > 10 V risks thermal runaway due to positive R_DS(on) temperature coefficient.

Does the built-in Zener protect against negative gate-source voltage transients?

Yes-the back-to-back Zener configuration provides symmetrical ±30 V clamping (V_(BR)GSO = ±30 V per Table 8), protecting against both positive and negative gate overvoltage events, including those induced by transformer leakage inductance or layout parasitics.

Is STQ3N45K3-AP RoHS-compliant and halogen-free?

Yes-this device is manufactured in ST's ECOPACK®-compliant TO-92 Ammopak package, meeting RoHS Directive 2011/65/EU and halogen-free requirements per IEC 61249-2-21, as confirmed in the official package mechanical data section of DocID024887 Rev 1.

STQ3N45K3-AP Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: SuperMESH3™

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 450 V

Current - Continuous Drain (Id) @ 25°C:: 600mA (Tc)

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

Rds On (Max) @ Id, Vgs:: 3.8Ohm @ 500mA, 10V

Vgs(th) (Max) @ Id:: 4.5V @ 50µA

Gate Charge (Qg) (Max) @ Vgs:: 6 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 150 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 3W (Tc)

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

STQ3N45K3-AP FAQ

1.How can I place an order for STQ3N45K3-AP through Aetrix?

Please submit a Request for Quotation (RFQ) for STQ3N45K3-AP 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 STQ3N45K3-AP reliable?

The price and inventory of STQ3N45K3-AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STQ3N45K3-AP is usually 5 days.

3.What payment methods are accepted for STQ3N45K3-AP?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STQ3N45K3-AP transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STQ3N45K3-AP?

STQ3N45K3-AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STQ3N45K3-AP 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 STQ3N45K3-AP?

For technical support, including STQ3N45K3-AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STQ3N45K3-AP requirements.

6.How does Aetrix verify that STQ3N45K3-AP is sourced from the original manufacturer or authorized distributors?

All STQ3N45K3-AP 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 STQ3N45K3-AP meets industry standards.

7.What is the process for return or replacement of STQ3N45K3-AP?

All STQ3N45K3-AP units undergo pre-shipment inspection (PSI). If there is an issue with STQ3N45K3-AP, 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 STQ3N45K3-AP part is unused and in its original packaging.

Return procedure for STQ3N45K3-AP:

1.Submit a request within 90 days.

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

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