STMicroelectronics STW29NK50Z

Overview

STW29NK50Z from STMicroelectronics is an N-channel 500 V, 31 A, 0.105 Ω R_DS(on) SuperMESH™ power MOSFET in TO-247 package, featuring integrated gate-source Zener protection, 100% avalanche tested, and optimized for high-speed switching in off-line SMPS. It delivers 350 W total dissipation at T_C = 25°C and supports 4.5 V/ns dv/dt capability.

For engineers reviewing the STW29NK50Z datasheet, STW29NK50Z pinout, STW29NK50Z application, or STW29NK50Z equivalent, key selection factors include its 500 V blocking voltage, low gate charge (190 nC), robust unclamped inductive switching performance (E_AS = 550 mJ), and built-in ±30 V gate-source Zener clamping-critical for rugged flyback and resonant converter designs.

Technical Context

This MOSFET employs ST's SuperMESH™ strip-based layout to minimize R_DS(on) while preserving high dv/dt immunity and low intrinsic capacitances (C_iss = 6110 pF, C_oss = 697 pF). Its gate threshold voltage (3.0–4.5 V) and forward transconductance (24 S) support stable drive across industrial temperature ranges.

The integrated back-to-back gate-source Zener diodes provide ±30 V clamping with 6000 V HBM ESD rating, eliminating external gate protection components. Avalanche ruggedness is validated per I_AR = 31 A and single-pulse E_AS = 550 mJ at T_j = 25°C, enabling reliable operation under transient overvoltage conditions.

Key Specifications

Pinout & Package

TO-247 package: isolated metal tab (drain), three leads - pin 1 (gate), pin 2 (drain), pin 3 (source). Drain connected to case for direct heatsinking; source and gate electrically isolated.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STW29NK50Z, STW34NB20 trades voltage headroom for lower conduction loss in sub-200 V systems, while IPP60R099C6 offers higher voltage margin and superior high-frequency efficiency-but demands revised gate drive design and layout practices.

Availability

STW29NK50Z is available at Aetrix Electronics and suitable for off-line power supplies, industrial welding equipment, electronic lighting ballasts, and UPS output stages requiring stable component supply and long-term industrial lifecycle support.

Supply support for STW29NK50Z 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, designing and manufacturing analog, power, MCU, and sensor solutions for automotive, industrial, and consumer markets.

The SuperMESH™ MOSFET product line targets high-reliability, high-efficiency power conversion systems where ruggedness, avalanche tolerance, and consistent parametric performance across temperature are essential.

FAQ

Is STW29NK50Z still in active production?

No-STW29NK50Z is marked "Obsolete Product(s)" in the official STMicroelectronics datasheet (Rev. 1, October 2004). It remains available through authorized legacy distributors and Aetrix Electronics' extended-life inventory program with full traceability and guaranteed authenticity.

What is the maximum safe operating temperature for continuous operation?

The maximum operating junction temperature is 150°C. At T_C = 100°C, the continuous drain current is derated to 19.5 A. Thermal design must ensure R_thj-case ≤ 0.36 °C/W and maintain T_j ≤ 150°C under worst-case ambient and power dissipation conditions.

Can STW29NK50Z be used without external gate resistors?

No-external gate resistors are required to control switching speed, damp ringing, and limit peak gate current. The 190 nC total gate charge and 111 nC Q_gd necessitate careful RG selection (typically 4.7–22 Ω) to balance EMI, losses, and dv/dt immunity per application circuit requirements.

Does the integrated Zener protect against negative gate pulses?

Yes-the back-to-back Zener configuration provides symmetrical ±30 V clamping between gate and source, protecting against both positive and negative transients. This eliminates the need for discrete bidirectional TVS devices and ensures robustness during gate driver startup/shutdown and fault recovery sequences.