STMicroelectronics STP14NK50Z

Overview

STP14NK50Z from STMicroelectronics is a Zener-protected N-channel SuperMESH Power MOSFET rated for 500 V drain-source voltage, 340 mΩ typical R_DS(on), and 14 A continuous drain current at T_C = 25 °C in TO-220 package. It delivers high dv/dt capability (4.5 V/ns), 100% avalanche tested operation (E_AS = 400 mJ), and minimized gate charge (Q_g = 69–92 nC), enabling robust performance in offline SMPS and AC-DC adapters.

For engineers reviewing the STP14NK50Z datasheet, STP14NK50Z pinout, STP14NK50Z application, or STP14NK50Z equivalent, key selection criteria include its 500 V breakdown rating, 340 mΩ on-resistance at 10 V gate drive, 48 A pulsed drain current, 150 W power dissipation, and TO-220 thermal resistance (R_thJC = 3.6 °C/W).

Technical Context

This device implements ST's SuperMESH process - an evolution of PowerMESH - optimizing cell pitch and gate oxide to reduce R_DS(on) while maintaining ruggedness. Its Zener-protected gate ensures ±30 V V_GS tolerance and 4 kV HBM ESD immunity, critical for high-noise industrial switching environments.

The MOSFET exhibits low output capacitance (C_oss = 238 pF) and reverse transfer capacitance (C_rss = 55 pF), supporting fast switching with measured t_d(off) = 54 ns and t_f = 12 ns under 4.7 Ω gate resistance. Its source-drain diode features t_rr = 470 ns and Q_rr = 3.1 µC at 150 °C, suitable for hard-switched flyback and resonant topologies.

Key Specifications

Pinout & Package

STP14NK50Z uses TO-220 package (Type A) with isolated tab. The metal tab is electrically connected to the drain terminal, requiring insulating mounting hardware when mounted to grounded heat sinks.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP14NK50Z, STP16NF50 offers lower conduction loss but increases system-level protection complexity, while IPP60R099C6 provides superior efficiency at the expense of through-hole compatibility and gate robustness - making STP14NK50Z optimal for cost-sensitive, serviceable, high-reliability AC-DC platforms.

Availability

STP14NK50Z is available at Aetrix Electronics and suitable for AC-DC adapters, industrial motor control pre-charge circuits, and LED driver bulk switches requiring stable component supply across multi-year production cycles.

Supply support for STP14NK50Z 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 microcontrollers, power devices, sensors, and analog ICs for industrial, automotive, and consumer markets.

STP14NK50Z belongs to the SuperMESH Power MOSFET product line, engineered specifically for high-efficiency, high-reliability offline switching applications where avalanche ruggedness and gate robustness are non-negotiable.

FAQ

Is STP14NK50Z suitable for zero-voltage switching (ZVS) topologies?

Yes - its low C_oss (238 pF) and C_rss (55 pF), combined with 4.5 V/ns dv/dt capability, support reliable ZVS operation in LLC resonant converters up to 300 kHz. Measured t_d(off) = 54 ns and t_f = 12 ns ensure tight timing control during resonant transitions without shoot-through risk.

What is the maximum recommended gate resistor value for reliable switching?

A gate resistor of 10–22 Ω is recommended for standard 65–100 kHz flyback operation. At 10 V drive, Q_g = 69–92 nC yields t_on/t_off < 100 ns with 10 Ω, balancing switching loss and EMI. Values >47 Ω increase switching losses disproportionately due to extended Miller plateau duration.

Does the TO-220 package require thermal compound when mounted to a heatsink?

Yes - ST specifies minimum thermal interface material (TIM) conductivity ≥1 W/m·K. With R_thJC = 3.6 °C/W and R_thCS ≈ 0.5 °C/W using standard grease, junction-to-sink resistance remains ≤4.1 °C/W, enabling 150 W dissipation only if heatsink ambient stays ≤45 °C.

Can STP14NK50Z replace STP12NK50Z in existing designs?

Yes - both share identical TO-220 footprint, pinout, and 500 V rating, but STP14NK50Z offers 14 A vs. 12 A I_D, 340 mΩ vs. 380 mΩ R_DS(on), and improved E_AS (400 mJ vs. 320 mJ). No layout or drive changes are needed; thermal margin improves by ~12% at full load.