STMicroelectronics STU5N95K3

Overview

STU5N95K3 from STMicroelectronics is an N-channel 950 V, 3.5 Ω (max), 4 A MDmesh K3 Power MOSFET in DPAK (TO-252) package, featuring 100% avalanche tested operation, 5 V/ns dv/dt capability, and Zener-protected gate, designed for high-voltage switching in offline SMPS and PFC stages.

For engineers reviewing the STU5N95K3 datasheet, STU5N95K3 pinout, STU5N95K3 application, or STU5N95K3 equivalent, key selection criteria include R_DS(on) at 10 V, E_AS = 100 mJ, C_oss = 38 pF, t_rr = 410 ns, and thermal resistance R_thJC = 1.39 °C/W - all critical for hard-switched flyback and resonant converter reliability.

Technical Context

This device employs ST's optimized vertical MDmesh K3 structure to achieve ultra-low on-resistance while maintaining robust 950 V breakdown voltage and superior dynamic performance. Its Zener-protected gate ensures ESD resilience, and its low C_iss/C_oss ratio supports high-frequency operation up to 100 kHz in continuous conduction mode PFC.

The integrated body diode delivers improved reverse recovery (Q_rr = 3.5 µC, I_RRM = 17 A) and reduced switching losses in bridge-leg configurations. Avalanche ruggedness (I_AR = 4 A, E_AS = 100 mJ) enables unclamped inductive load handling without external snubbers.

Key Specifications

Pinout & Package

DPAK (TO-252) package with exposed drain tab (Pin 2) for thermal and electrical connection; standard 3-pin configuration with G-S-D layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP5N95K3 and STF5N95K3, STU5N95K3 offers optimal PCB integration density and thermal interface simplicity via DPAK's surface-mount tab, making it ideal for automated assembly and space-constrained power modules.

Availability

STU5N95K3 is available at Aetrix Electronics and suitable for industrial AC/DC power supplies, telecom rectifiers, and LED streetlight drivers requiring stable component supply across multi-year production cycles.

Supply support for STU5N95K3 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, specializing in power, analog, MEMS, and microcontroller technologies for industrial, automotive, and consumer markets.

The MDmesh K3 product line targets high-efficiency, high-reliability high-voltage power conversion, specifically engineered for 800 V+ DC bus architectures in server PSUs, telecom infrastructure, and renewable energy interfaces.

FAQ

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

The STU5N95K3 supports 3 A continuous drain current at T_C = 100 °C, per Table 1 of DS6265 Rev 4. This derating reflects thermal limits of the DPAK package and ensures safe operation within SOA boundaries without exceeding T_J = 150 °C under typical PCB copper area conditions.

Does STU5N95K3 require a gate resistor for reliable switching?

Yes - a 4.7 Ω gate resistor is specified in the datasheet's switching time test circuit (Figure 14) to control dV/dt and prevent oscillation. Lower values increase switching speed but risk ringing; higher values reduce EMI but raise switching losses. Typical design uses 4.7–10 Ω for 75–100 kHz operation.

Can STU5N95K3 replace STD5N95K3 in existing designs?

No - STU5N95K3 and STD5N95K3 share identical electrical specs and die, but differ in package type: STD5N95K3 uses DPAK Type A2, while STU5N95K3 uses DPAK Type C3. Mechanical footprint and thermal pad dimensions differ (e.g., D1 = 5.20–5.70 mm for C3 vs. 4.95–5.25 mm for A2), requiring PCB layout revision.

Is the body diode suitable for synchronous rectification?

No - while the body diode exhibits improved t_rr (410 ns) and low Q_rr (3.5 µC), it is not optimized for bidirectional conduction. For synchronous rectification, discrete Schottky or dedicated SR controllers with external FETs are recommended to avoid reverse recovery losses and ensure precise timing control.