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

STMicroelectronics STD5NK40ZT4

Name: STD5NK40ZT4
Brand: STMicroelectronics
SKU: STD5NK40ZT4
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STD5NK40ZT4

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Datasheet:: STD5NK40ZT4.pdf

Description:: MOSFET N-CH 400V 3A DPAK

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Product details

Overview

STD5NK40ZT4 from STMicroelectronics is an N-channel 400 V, 1.47 Ω (typ), 3 A Zener-protected SuperMESH™ power MOSFET in DPAK (TO-252) package, designed for high-speed switching in offline SMPS, PFC stages, and lighting ballasts with robust avalanche capability and minimized gate charge.

For engineers reviewing the STD5NK40ZT4 datasheet, STD5NK40ZT4 pinout, STD5NK40ZT4 application, or STD5NK40ZT4 equivalent, key selection criteria include R_DS(on) at 10 V, 100% avalanche rating (E_AS = 130 mJ), dv/dt immunity (4.5 V/ns), thermal resistance (R_thj-case = 2.77 °C/W), and integrated gate-source Zener protection (±30 V).

Technical Context

This MOSFET employs ST's optimized strip-based PowerMESH™ layout to achieve low on-resistance while maintaining extreme dv/dt immunity-critical for hard-switched flyback and boost converters operating near line transients. Its built-in back-to-back gate-source Zener diodes (BVGSO = 30 V) eliminate external clamping components without sacrificing ESD robustness (VESD(G-S) = 2800 V).

The device features low intrinsic capacitances (C_iss = 305 pF, C_oss = 57 pF, C_rss = 11.5 pF) and fast switching (t_d(on) = 9.2 ns, t_f = 11 ns), enabling high-frequency operation up to 100 kHz in continuous conduction mode PFC designs with minimal switching loss.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	400 V - supports universal AC input (85–265 VAC) with margin for surge and ringing in offline topologies
R_DS(on) (typ)	1.47 Ω @ V_GS = 10 V - enables <3 W conduction loss at 3 A DC, suitable for compact 30–60 W adapters
I_D (cont)	3 A @ T_C = 25°C - rated for sustained current in thermally constrained DPAK footprint
E_AS	130 mJ - guarantees unclamped inductive switching survival in PFC and flyback snubberless designs
Q_g	11.7 nC - reduces gate drive power and allows use of low-cost bipolar or small SOT-23 drivers
dv/dt Rating	4.5 V/ns - prevents spurious turn-on during fast voltage transitions in high-side configurations
R_thj-case	2.77 °C/W - enables >25 W dissipation with standard 2-layer PCB copper pour (≥10 cm²)

Pinout & Package

STD5NK40ZT4 is housed in a surface-mount DPAK (TO-252) package with exposed drain pad for thermal enhancement and mechanical stability. The package complies with JEDEC TO-252-2 standard and supports automated reflow assembly.

Pin/Terminal	Circuit Role	Design Meaning
1 (Gate)	Control input	Receives 10 V logic-level signal; protected by integrated ±30 V Zener clamp
2 (Drain)	High-side switch node	Connected to primary winding or bus rail; electrically tied to exposed metal tab for heatsinking
3 (Source)	Power return / reference	Serves as local ground reference for gate driver; carries full load current and body diode conduction

Key Features

Feature	Design Value
Zener-protected gate	Integrated back-to-back Zeners (±30 V) replace external TVS, reducing BOM count and board space
100% avalanche tested	Each unit validated for repetitive I_AR = 3 A and single-pulse E_AS = 130 mJ - ensures field reliability in unregulated loads
Minimized Q_g & C_iss	11.7 nC total gate charge and 305 pF input capacitance enable efficient 65–100 kHz switching with low driver loss
Low R_thj-case	2.77 °C/W junction-to-case thermal resistance allows direct mounting to copper pour without clip or thermal pad
High dv/dt immunity	4.5 V/ns rated slope prevents false triggering in noisy high-voltage nodes common in offline converters

Applications

Offline AC-DC Adapters

Active PFC Stages

Use Scenario: 36 W universal-input adapter with quasi-resonant flyback topology.

IC Role / Device Role: Primary-side high-voltage switching element handling 400 V DC bus and 3 A peak current.

Use Value: Low R_DS(on) and 130 mJ avalanche energy ensure no failure during line surges or output short-circuit events.

Use Scenario: Boost-type active PFC in 65 W LED driver for commercial lighting.

IC Role / Device Role: Switching transistor in continuous conduction mode (CCM) boost converter operating at 65 kHz.

Use Value: Minimized Q_g (11.7 nC) and low C_oss (57 pF) reduce switching losses and improve efficiency above 93%.

Electronic Ballasts

Industrial Control Power Supplies

Use Scenario: High-frequency electronic ballast for T5 fluorescent lamps (25–60 kHz).

IC Role / Device Role: Half-bridge switch driving resonant tank with fast zero-voltage switching transitions.

Use Value: 4.5 V/ns dv/dt rating prevents parasitic turn-on during rapid V_DS transitions across resonant cycle.

Use Scenario: 24 V/3 A auxiliary supply in PLC backplane with wide ambient temperature range (−40°C to +85°C).

IC Role / Device Role: Primary-side switch in isolated forward converter with synchronous rectification.

Use Value: Stable R_DS(on) over temperature (±15% from −55°C to 150°C) ensures consistent regulation under thermal stress.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP5NK40Z	Same die, TO-220 package; R_thj-case = 2.77 °C/W but higher R_thj-amb (62.5 °C/W); no tape-and-reel option	Requires through-hole assembly and heatsink mounting; unsuitable for high-density SMT production	Select when manual prototyping or low-volume through-hole builds prioritize thermal test flexibility over automation.
FQP3N40	400 V, 3 A, R_DS(on) = 2.2 Ω (typ); no integrated Zener; E_AS not specified; lower dv/dt rating	Lacks gate protection and avalanche validation - requires external clamping and derating in harsh environments	Choose only for cost-sensitive, non-safety-critical 24 V input applications where surge immunity is managed externally.

Compared with STP5NK40Z and FQP3N40, STD5NK40ZT4 uniquely combines DPAK SMT compatibility, factory-validated avalanche ruggedness, and integrated gate Zener protection-enabling smaller, more reliable, and fully automated power stage designs without compromise on transient robustness.

Availability

STD5NK40ZT4 is available at Aetrix Electronics and suitable for offline AC-DC adapters, active PFC modules, and electronic ballasts requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial and lighting OEMs.

Supply support for STD5NK40ZT4 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, delivering silicon solutions for automotive, industrial, and power management applications since 1987.

STD5NK40ZT4 belongs to ST's SuperMESH™ high-voltage MOSFET product line, engineered specifically for high-efficiency, high-reliability offline switching power supplies where avalanche ruggedness, low gate charge, and thermal performance are critical.

FAQ

Is STD5NK40ZT4 pin-compatible with other DPAK MOSFETs like STP5NK40ZFP?

No - STD5NK40ZT4 uses standard DPAK (TO-252) pinout (G-D-S), while STP5NK40ZFP is in TO-220FP (a different package with distinct lead configuration and thermal path). Physical replacement requires PCB redesign; electrical parameters alone do not guarantee drop-in substitution.

What is the maximum recommended gate resistor value for driving STD5NK40ZT4 at 100 kHz?

Based on Q_g = 11.7 nC and typical 12 V gate drive, a 10 Ω series resistor limits peak current to ~1.2 A and achieves ~120 ns turn-on delay - sufficient for 100 kHz operation. Values above 22 Ω increase switching loss significantly; below 4.7 Ω require careful layout to avoid ringing.

Does STD5NK40ZT4 require external gate protection when used with a microcontroller GPIO?

No - its integrated ±30 V gate-source Zener diodes provide full protection against ESD (2800 V HBM) and transient overvoltage. However, a 10–22 Ω series gate resistor is still recommended to dampen oscillation and limit peak current during fast edge transitions.

Can STD5NK40ZT4 be used in linear regulator applications?

No - it is optimized for switching operation only. Its SOA curve shows limited safe operating area in linear mode (e.g., <1 W at V_DS = 200 V), and prolonged linear operation risks thermal runaway due to positive temperature coefficient of R_DS(on).

STD5NK40ZT4 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: SuperMESH™

Package/Case:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Packaging:: Tape & Reel (TR)

Product Status:: Active

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 400 V

Current - Continuous Drain (Id) @ 25°C:: 3A (Tc)

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

Rds On (Max) @ Id, Vgs:: 1.8Ohm @ 1.5A, 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:: 305 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 45W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DPAK

STD5NK40ZT4 FAQ

1.How can I place an order for STD5NK40ZT4 through Aetrix?

Please submit a Request for Quotation (RFQ) for STD5NK40ZT4 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 STD5NK40ZT4 reliable?

The price and inventory of STD5NK40ZT4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STD5NK40ZT4 is usually 5 days.

3.What payment methods are accepted for STD5NK40ZT4?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STD5NK40ZT4 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STD5NK40ZT4?

STD5NK40ZT4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STD5NK40ZT4 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 STD5NK40ZT4?

For technical support, including STD5NK40ZT4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STD5NK40ZT4 requirements.

6.How does Aetrix verify that STD5NK40ZT4 is sourced from the original manufacturer or authorized distributors?

All STD5NK40ZT4 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 STD5NK40ZT4 meets industry standards.

7.What is the process for return or replacement of STD5NK40ZT4?

All STD5NK40ZT4 units undergo pre-shipment inspection (PSI). If there is an issue with STD5NK40ZT4, 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 STD5NK40ZT4 part is unused and in its original packaging.

Return procedure for STD5NK40ZT4:

1.Submit a request within 90 days.

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

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