STMicroelectronics STB11NK50ZT4

Overview

STB11NK50ZT4 from STMicroelectronics is a Zener-protected N-channel SuperMESH Power MOSFET rated for 500 V drain-source voltage, 470 mΩ typical R_DS(on), and 10 A continuous drain current at T_C = 25 °C, housed in a D²PAK (TO-263) package. It delivers high dv/dt capability and 100% avalanche-tested ruggedness for hard-switching power conversion stages in industrial SMPS and offline AC-DC adapters.

For engineers reviewing the STB11NK50ZT4 datasheet, STB11NK50ZT4 pinout, STB11NK50ZT4 application, or STB11NK50ZT4 equivalent, key selection criteria include its 190 mJ single-pulse avalanche energy, 49 nC total gate charge, 1390 pF input capacitance, and thermal resistance of 1 °C/W junction-to-case - all critical for snubberless flyback and resonant converter reliability and efficiency.

Technical Context

This device implements ST's SuperMESH process - an evolution of PowerMESH - to simultaneously reduce on-resistance and intrinsic capacitance while maintaining robust avalanche performance. Its Zener-protected gate ensures ±30 V V_GS tolerance and 4 kV HBM ESD rating.

The MOSFET supports unclamped inductive switching with 10 A repetitive avalanche current and exhibits low reverse recovery charge (2.4 µC) and fast diode recovery time (308 ns at T_J = 150 °C), enabling high-frequency operation in quasi-resonant topologies without external freewheeling diode stress.

Key Specifications

Pinout & Package

STB11NK50ZT4 is packaged in D²PAK (TO-263), a surface-mount variant of TO-220 with exposed drain tab for enhanced thermal transfer to PCB copper. The package features gull-wing leads and is RoHS-compliant per ECOPACK2 specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP11NK50Z, STB11NK50ZT4 offers superior thermal performance and SMT compatibility; versus FQP11N50CT, it provides verified avalanche ruggedness and integrated gate protection - critical for field-reliable power systems.

Availability

STB11NK50ZT4 is available at Aetrix Electronics and suitable for industrial SMPS, offline AC-DC adapters, LED driver systems, and UPS DC-DC stages requiring stable component supply and long-term lifecycle support.

Supply support for STB11NK50ZT4 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.

STB11NK50ZT4 belongs to the SuperMESH Power MOSFET product line, engineered specifically for high-efficiency, high-reliability offline power conversion where avalanche robustness, low gate charge, and thermal performance are mandatory.

FAQ

What is the maximum safe operating temperature for STB11NK50ZT4?

The device has a specified junction temperature range of −55 °C to +150 °C. Continuous operation at T_J = 150 °C requires limiting power dissipation to maintain thermal equilibrium - for example, at 10 A drain current, R_DS(on) rises to ~750 mΩ, demanding ≤125 W total power with R_thJC = 1 °C/W and case temperature held below 25 °C via aggressive heatsinking.

Does STB11NK50ZT4 require external gate protection?

No. The integrated Zener diode between gate and source provides ±30 V clamping, making external gate protection unnecessary in most industrial applications. However, a 10–100 Ω series gate resistor remains essential to dampen ringing and limit peak gate current during fast switching transitions.

Can STB11NK50ZT4 replace STP11NK50Z in existing TO-220 layouts?

No direct footprint replacement is possible: STB11NK50ZT4 uses D²PAK (TO-263) with gull-wing leads and an exposed drain tab, whereas STP11NK50Z uses TO-220 with through-hole pins. PCB redesign is required to accommodate surface-mount pads, thermal copper area, and reflow profile adjustments.

What is the significance of "100% avalanche tested" in production?

Every unit undergoes individual unclamped inductive switching test at I_AR = 10 A and V_DD = 50 V, verifying minimum 190 mJ single-pulse avalanche energy. This guarantees consistent ruggedness across lots - unlike statistical sampling - ensuring reliability in surge-prone mains-connected equipment.