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

STMicroelectronics STB5NK50Z-1

Name: STB5NK50Z-1
Brand: STMicroelectronics
SKU: STB5NK50Z-1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STB5NK50Z-1

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-262-3 Long Leads, I2PAK, TO-262AA

Datasheet:: STB5NK50Z-1.pdf

Description:: MOSFET N-CH 500V 4.4A I2PAK

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Product details

Overview

STB5NK50Z-1 from STMicroelectronics is a Zener-protected N-channel SuperMESH™ Power MOSFET in I2PAK package, rated for 500 V drain-source voltage, 1.22 Ω typical R_DS(on), and 4.4 A continuous drain current at T_C = 25 °C. It delivers high dv/dt capability (4.5 V/ns), 100% avalanche tested performance, and integrated gate-source Zener protection - deployed in offline SMPS primary-side switching and AC-DC adapter power stages.

For engineers reviewing the STB5NK50Z-1 datasheet, STB5NK50Z-1 pinout, STB5NK50Z-1 application, or STB5NK50Z-1 equivalent, this device requires verification of thermal resistance (R_thj-case = 1.78 °C/W), gate charge (Q_g = 20–28 nC), reverse recovery characteristics (t_rr = 310 ns), and safe operating area limits under unclamped inductive load conditions.

Technical Context

This MOSFET employs ST's SuperMESH™ process to minimize R_DS(on) while maintaining robust avalanche ruggedness (E_AS = 130 mJ) and low intrinsic capacitance (C_iss = 535 pF, C_oss = 75 pF). Its built-in back-to-back gate-source Zener diodes provide ±30 V breakdown protection without external clamping components.

The device operates across –55 to 150 °C junction temperature range and supports fast switching with turn-on delay t_d(on) = 15 ns and fall time t_f = 15 ns under 4.7 Ω gate drive. Its source-drain diode exhibits V_SD = 1.6 V at 4.4 A and reverse recovery charge Q_rr = 1.425 µC at 150 °C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	500 V - Withstands full mains rectified voltage in 230 VAC offline converters without derating.
R_DS(on) max	1.5 Ω - Ensures <1.5 W conduction loss at 4.4 A DC, enabling compact heatsink design.
I_D cont. (T_C=25°C)	4.4 A - Supports up to 150 W output in flyback topologies with adequate PCB copper area.
Q_g	20–28 nC - Enables efficient 100–300 kHz switching with standard gate drivers (e.g., UC384x series).
E_AS	130 mJ - Guarantees single-pulse avalanche survival during transformer leakage energy dissipation.
t_rr	310 ns - Limits switching losses and EMI generation during hard-commutated inductive turn-off.
R_thj-case	1.78 °C/W - Allows direct mounting to heatsink with ≤70 W total dissipation at T_C = 25 °C.

Pinout & Package

I2PAK (TO-262) package with isolated tab: thermally conductive metal tab (Drain-connected), 3-pin through-hole outline, ECOPACK® compliant, 13–14 mm body length, 8.95–9.35 mm width, and 4.40–4.60 mm height. Tab must be electrically insulated from heatsink unless Drain reference is system ground.

Pin/Terminal	Circuit Role	Design Meaning
1 (G)	Gate	High-impedance control terminal requiring <28 nC charge for full enhancement; sensitive to ESD (HBM = 3 kV).
2 (D)	Drain	Main high-voltage power terminal; connected internally to metal tab; must be isolated from heatsink unless referenced to HV rail.
3 (S)	Source	Power return path and gate reference node; forms common-source configuration with low-inductance layout critical for dv/dt immunity.

Key Features

Feature	Design Value
100% avalanche tested	Every unit validated for E_AS ≥130 mJ - eliminates field failure risk in unclamped inductive switching.
Zener-protected gate	Integrated ±30 V gate-source Zener - removes need for external TVS, reducing BOM count and layout area.
Minimized gate charge	Q_g = 20–28 nC - cuts driver power loss and enables higher-frequency operation without gate driver oversizing.
Very low C_oss	75 pF output capacitance - reduces turn-off energy loss (½ × C_oss × V_DS²) in hard-switched topologies.
High dv/dt immunity	4.5 V/ns rated slope - prevents spurious turn-on in noisy high-side configurations with fast-rising drain transients.

Applications

Offline AC-DC Adapters

Flyback SMPS Primary Switch

Use Scenario: 230 VAC input, 12 V/10 W output flyback converter in wall-mounted charger.

IC Role / Device Role / Timing Role: Primary-side power switch controlling energy transfer via transformer during each PWM cycle.

Use Value: 1.22 Ω R_DS(on) keeps conduction loss below 0.8 W at full load; Zener protection avoids gate oxide rupture during line surges.

Use Scenario: Industrial 24 V/30 W open-frame power supply with universal AC input.

IC Role / Device Role / Timing Role: High-voltage switching element in discontinuous conduction mode (DCM) flyback topology.

Use Value: 130 mJ E_AS ensures reliable operation during transformer saturation events; 310 ns t_rr minimizes cross-conduction loss with synchronous rectification.

LED Driver Power Stage

DC-DC Boost Converter Input Switch

Use Scenario: Constant-current LED driver for street lighting using 350 V bus derived from PFC stage.

IC Role / Device Role / Timing Role: Main switching transistor regulating LED current via peak-current-mode control.

Use Value: 500 V V_DS rating accommodates PFC ripple without margin compromise; 4.5 V/ns dv/dt rating suppresses false triggering in high-noise lamp environments.

Use Scenario: 48 V input, 400 V output boost converter in telecom power shelf.

IC Role / Device Role / Timing Role: Low-side switch in non-isolated boost stage handling 5–8 A average input current.

Use Value: 1.78 °C/W R_thj-case allows direct heatsink mounting for 25 W dissipation; 1.5 Ω max R_DS(on) limits resistive loss to <1.2 W at 9 A pulsed peak.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP5NK50Z	Same die, TO-220 package; R_thj-case = 1.78 °C/W but larger footprint and no isolated tab.	Requires mechanical isolation kit for heatsink mounting; less suitable for space-constrained PCBs.	Select when legacy TO-220 socket compatibility or lower assembly cost is prioritized over thermal density.
STD5NK50ZT4	DPAK package; R_thj-case = 5.0 °C/W; same V_DS/R_DS(on)/I_D ratings but lower power dissipation limit (25 W vs 70 W).	Restricted to ≤15 W continuous operation; suited for SMT-only production and compact adapters.	Select for automated assembly and board-level thermal management where peak power is capped at 12 W.

Compared with STP5NK50Z and STD5NK50ZT4, STB5NK50Z-1 offers superior thermal performance per unit volume due to its I2PAK isolated-tab construction, enabling higher power density in constrained layouts while retaining identical electrical ruggedness and Zener protection.

Availability

STB5NK50Z-1 is available at Aetrix Electronics and suitable for offline AC-DC adapters, industrial flyback SMPS, and LED driver power stages requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for STB5NK50Z-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, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

STB5NK50Z-1 belongs to the SuperMESH™ Power MOSFET product line, engineered specifically for high-efficiency, high-reliability switching in 500 V-class offline power conversion systems.

FAQ

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

The STB5NK50Z-1 supports 2.7 A continuous drain current at T_C = 100 °C, as specified in Table 1 of DS2834 Rev 6. This derating reflects thermal limitations of the I2PAK package and must be applied when ambient temperature or heatsink performance restricts case temperature rise.

Is the metal tab electrically connected to the Drain terminal?

Yes, the exposed metal tab in the I2PAK package is internally bonded to the Drain terminal. Electrical isolation from the heatsink is mandatory unless the heatsink is referenced to the high-voltage Drain potential - verified via creepage/clearance compliance per IEC 62368-1.

Does STB5NK50Z-1 require an external gate resistor for stability?

A gate resistor (typically 4.7 Ω) is required to dampen ringing and control switching speed, as confirmed by Figure 15 and Table 6 test conditions. Omitting it risks oscillation due to PCB trace inductance interacting with Q_gd and C_iss, especially at >100 kHz.

Can STB5NK50Z-1 replace STP5NK50Z in existing TO-220 designs?

No direct drop-in replacement: STB5NK50Z-1 uses I2PAK (TO-262) with different pin pitch (2.54 mm vs 5.08 mm), tab orientation, and mounting hole pattern. PCB redesign and thermal validation are required; however, electrical behavior and SOA curves are identical per DS2834.

STB5NK50Z-1 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: SuperMESH™

Package/Case:: TO-262-3 Long Leads, I2PAK, TO-262AA

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:: 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:: 28 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 535 pF @ 25 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-262 (I2PAK)

STB5NK50Z-1 FAQ

1.How can I place an order for STB5NK50Z-1 through Aetrix?

Please submit a Request for Quotation (RFQ) for STB5NK50Z-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 STB5NK50Z-1 reliable?

The price and inventory of STB5NK50Z-1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STB5NK50Z-1 is usually 5 days.

3.What payment methods are accepted for STB5NK50Z-1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STB5NK50Z-1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STB5NK50Z-1?

STB5NK50Z-1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STB5NK50Z-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 STB5NK50Z-1?

For technical support, including STB5NK50Z-1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STB5NK50Z-1 requirements.

6.How does Aetrix verify that STB5NK50Z-1 is sourced from the original manufacturer or authorized distributors?

All STB5NK50Z-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 STB5NK50Z-1 meets industry standards.

7.What is the process for return or replacement of STB5NK50Z-1?

All STB5NK50Z-1 units undergo pre-shipment inspection (PSI). If there is an issue with STB5NK50Z-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 STB5NK50Z-1 part is unused and in its original packaging.

Return procedure for STB5NK50Z-1:

1.Submit a request within 90 days.

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

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