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

STMicroelectronics STD3NK50Z-1

Name: STD3NK50Z-1
Brand: STMicroelectronics
SKU: STD3NK50Z-1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STD3NK50Z-1

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

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

Datasheet:: STD3NK50Z-1.pdf

Description:: MOSFET N-CH 500V 2.3A IPAK

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Product details

Overview

STD3NK50Z-1 from STMicroelectronics is an N-channel 500 V, 2.3 A, 2.8 Ω (typ) Zener-protected SuperMESH™ MOSFET in IPAK (TO-251) package, designed for high-voltage switching in offline SMPS and AC adapters. It features 100% avalanche tested ruggedness, 4.5 V/ns dv/dt capability, and integrated gate-source Zener protection (±30 V rating).

For engineers reviewing the STD3NK50Z-1 datasheet, STD3NK50Z-1 pinout, STD3NK50Z-1 application, or STD3NK50Z-1 equivalent, key selection criteria include R_DS(on) at 10 V drive, unclamped avalanche energy (120 mJ), thermal resistance (R_thj-case = 2.77 °C/W), and Zener-protected gate integrity under transient stress.

Technical Context

This MOSFET employs ST's SuperMESH™ layout-optimized strip-based PowerMESH™-to simultaneously reduce R_DS(on) and enhance dv/dt immunity. Its gate charge profile (Q_g = 11 nC, Q_gd = 5.6 nC) supports efficient hard-switching in 50–100 kHz flyback and forward converters.

The integrated back-to-back gate-source Zener diodes (BVGSO = 30 V) eliminate need for external clamping while enabling robust ESD tolerance (2000 V HBM) and safe handling of gate transients during board assembly or system fault conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	500 V - Withstands full mains-referenced DC bus in universal-input offline SMPS without derating.
R_DS(on) (typ)	2.8 Ω @ V_GS = 10 V, I_D = 1.15 A - Enables <1.5 W conduction loss at 2.3 A continuous drain current.
I_D (cont)	2.3 A @ T_C = 25°C - Sustains rated load in compact IPAK footprint with 45 W total dissipation.
E_AS	120 mJ @ T_j = 25°C - Absorbs unclamped inductive energy during MOSFET turn-off without failure.
dv/dt Capability	4.5 V/ns - Resists false triggering during fast voltage transients in high-noise power stages.
Q_g	11 nC - Reduces gate driver power demand and switching transition time in low-duty-cycle topologies.

Pinout & Package

STD3NK50Z-1 uses the IPAK (TO-251) surface-mount package with exposed drain pad for thermal and electrical performance. The three-terminal configuration provides direct PCB thermal coupling and simplified layout versus through-hole alternatives.

Pin/Terminal	Circuit Role	Design Meaning
1 (GATE)	Control input	Receives 0–10 V logic-level signal; protected by integrated ±30 V Zener clamp.
2 (DRAIN)	High-side switch node	Connected to primary winding or HV rail; electrically and thermally tied to exposed copper pad.
3 (SOURCE)	Return path / reference	Provides low-inductance return for gate drive loop and current sensing; ties to power ground plane.

Key Features

Feature	Design Value
Zener-protected gate	Integrated back-to-back Zeners (±30 V) replace external TVS, reducing BOM count and layout area.
100% avalanche tested	Each unit validated for 2.3 A repetitive avalanche current and 120 mJ single-pulse energy.
SuperMESH™ layout	Optimized cell geometry delivers 2.8 Ω R_DS(on) with 4.5 V/ns dv/dt immunity-critical for EMI-sensitive designs.
Low gate charge	Q_g = 11 nC and Q_gd = 5.6 nC minimize Miller-induced switching delay and driver losses.
IPAK thermal performance	R_thj-case = 2.77 °C/W enables 45 W dissipation on standard 1-in² FR4 with 2 oz Cu-no heatsink required.

Applications

AC Adapters

LED Drivers

Use Scenario: Universal-input (90–264 V_AC) offline flyback converter delivering 12–24 V/1–2 A for consumer electronics.

IC Role / Device Role / Timing Role: Primary-side high-voltage switch controlling energy transfer into transformer; operates at 65 kHz with DCM/CCM boundary control.

Use Value: 500 V rating avoids series stacking; 2.8 Ω R_DS(on) keeps conduction loss below 1.5 W at full load; Zener protection prevents gate damage during no-load overvoltage events.

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

IC Role / Device Role / Timing Role: Main power switch regulating output current via primary-side sensing; handles 400 V DC bus with tight duty cycle control.

Use Value: 4.5 V/ns dv/dt capability suppresses false triggering during valley switching; 120 mJ E_AS ensures reliability during output short-circuit recovery.

Industrial SMPS

Smart Meter Power Supplies

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

IC Role / Device Role / Timing Role: High-side switch in forward converter stage; driven by isolated gate driver with 10 V logic interface.

Use Value: R_DS(on) drift <15% from −40°C to 125°C ensures stable efficiency; 2.3 A I_D rating supports peak load surges without thermal runaway.

Use Scenario: Mains-powered utility meter with dual-output (5 V/3.3 V) isolated supply meeting IEC 62053 creepage/clearance requirements.

IC Role / Device Role / Timing Role: Primary switch in reinforced-isolation flyback; gate driven directly from microcontroller PWM with Zener clamping.

Use Value: 2000 V HBM ESD rating allows direct MCU connection without level-shifter; IPAK package meets creepage >5 mm on PCB.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP3NK50Z	TO-220 package; identical R_DS(on), V_DSS, and E_AS; higher R_thj-case (1.5 °C/W) but larger thermal mass.	Requires heatsink for >15 W dissipation; better suited for open-frame industrial supplies than space-constrained adapters.	Select when mechanical mounting flexibility and higher pulse current (I_DM = 9.2 A) outweigh PCB area constraints.
FQP3N50CTF	500 V, 3.3 Ω R_DS(on), 2.5 A I_D; no integrated Zener; lower E_AS (75 mJ); TO-220FP package.	Lacks gate protection-requires external 18 V Zener; less rugged in unclamped inductive switching.	Choose only if cost sensitivity dominates and gate drive circuit includes discrete clamping and layout minimizes transient coupling.

Compared with STP3NK50Z and FQP3N50CTF, STD3NK50Z-1 offers superior gate protection and thermal efficiency in surface-mount form, making it optimal for compact, high-reliability offline converters where Zener integration and IPAK thermal performance reduce system-level design risk.

Availability

STD3NK50Z-1 is available at Aetrix Electronics and suitable for AC adapters, LED drivers, and industrial SMPS requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for STD3NK50Z-1 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, with manufacturing, R&D, and sales operations across Europe, Asia, and the Americas.

STD3NK50Z-1 belongs to ST's SuperMESH™ high-voltage MOSFET product line, engineered specifically for efficiency-critical, space-constrained offline power conversion in consumer, industrial, and lighting applications.

FAQ

What is the maximum continuous drain current for STD3NK50Z-1 at 100°C case temperature?

The maximum continuous drain current is 1.45 A at T_C = 100°C, as specified in Table 3 of the official datasheet. This derating reflects thermal limits of the IPAK package and ensures safe operation within the SOA curve up to 150°C junction temperature.

Does STD3NK50Z-1 require an external gate resistor for stability in flyback applications?

A gate resistor of 4.7 Ω is recommended per Figure 19 test circuit and switching timing data (t_d(on), t_r, etc.). This value balances switching speed against ringing and EMI, especially given the device's 4.5 V/ns dv/dt capability and low Q_gd/Q_gs ratio.

Can STD3NK50Z-1 be used in place of STD3NK50Z without layout changes?

Yes-both share identical IPAK (TO-251) package dimensions, pinout, and thermal pad layout. STD3NK50Z-1 replaces STD3NK50Z in tube packaging (not tape-and-reel), but mechanical and electrical compatibility is maintained per ST's ordering documentation.

What is the source-drain diode forward voltage at 2.3 A?

The source-drain diode forward voltage is 1.6 V at I_SD = 2.3 A and V_GS = 0 V, as measured in Table 9. This body diode is optimized for low recovery charge (Q_rr = 745 µC at 25°C), supporting quasi-resonant and active-clamp topologies.

STD3NK50Z-1 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: SuperMESH™

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):: 500 V

Current - Continuous Drain (Id) @ 25°C:: 2.3A (Tc)

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

Rds On (Max) @ Id, Vgs:: 3.3Ohm @ 1.15A, 10V

Vgs(th) (Max) @ Id:: 4.5V @ 50µA

Gate Charge (Qg) (Max) @ Vgs:: 15 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 280 pF @ 25 V

FET Feature:: -

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

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: IPAK

STD3NK50Z-1 FAQ

1.How can I place an order for STD3NK50Z-1 through Aetrix?

Please submit a Request for Quotation (RFQ) for STD3NK50Z-1 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 STD3NK50Z-1 reliable?

The price and inventory of STD3NK50Z-1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STD3NK50Z-1 is usually 5 days.

3.What payment methods are accepted for STD3NK50Z-1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STD3NK50Z-1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STD3NK50Z-1?

STD3NK50Z-1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STD3NK50Z-1 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 STD3NK50Z-1?

For technical support, including STD3NK50Z-1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STD3NK50Z-1 requirements.

6.How does Aetrix verify that STD3NK50Z-1 is sourced from the original manufacturer or authorized distributors?

All STD3NK50Z-1 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 STD3NK50Z-1 meets industry standards.

7.What is the process for return or replacement of STD3NK50Z-1?

All STD3NK50Z-1 units undergo pre-shipment inspection (PSI). If there is an issue with STD3NK50Z-1, 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 STD3NK50Z-1 part is unused and in its original packaging.

Return procedure for STD3NK50Z-1:

1.Submit a request within 90 days.

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

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