STMicroelectronics STD5N95K3

Overview

STD5N95K3 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. It serves as a high-voltage switching device in offline SMPS, PFC stages, and industrial motor drives requiring robust unclamped inductive switching.

For engineers reviewing the STD5N95K3 datasheet, STD5N95K3 pinout, STD5N95K3 application, or STD5N95K3 equivalent, key selection criteria include its 950 V V(BR)DSS rating, low 3.5 Ω RDS(on) at 10 V VGS, 100 mJ single-pulse avalanche energy, and optimized diode recovery (trr = 410 ns, Qrr = 3.5 µC) for hard-switched topologies.

Technical Context

This device employs ST's MDmesh K3 vertical superjunction architecture with enhanced charge compensation, enabling ultra-low on-resistance while maintaining high breakdown voltage. Its dynamic performance is characterized by 460 pF Ciss, 19 nC total gate charge, and 17 ns turn-on delay under 475 V/2 A resistive load conditions.

The integrated source-drain diode exhibits improved reverse recovery (Qrr = 3.5 µC, IRRM = 17 A) and Zener protection clamps gate-source voltage to ±30 V, supporting reliable operation in high-dv/dt environments such as flyback and resonant converters.

Key Specifications

Pinout & Package

DPAK (TO-252) package with exposed drain tab (Pin 2) for thermal and electrical connection; thermally enhanced plastic surface-mount outline compliant with JEDEC TO-252 standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP5N95K3 and IPP50R950CE, STD5N95K3 uniquely balances 950 V rating, DPAK thermal performance (RthJC = 1.39 °C/W), and 4 A continuous current in surface-mount form-making it optimal for space-constrained, high-reliability offline power stages.

Availability

STD5N95K3 is available at Aetrix Electronics and suitable for industrial motor drives, server PSU PFC stages, and offline flyback converters requiring stable component supply across multi-year production cycles.

Supply support for STD5N95K3 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.

STD5N95K3 belongs to the MDmesh K3 high-voltage MOSFET product line, engineered specifically for high-efficiency, high-reliability offline switching power supplies and industrial motor control where avalanche ruggedness and fast diode recovery are critical.

FAQ

What is the maximum continuous drain current for STD5N95K3 at 100 °C case temperature?

The maximum continuous drain current is 3 A at TC = 100 °C, as specified in Table 1 of DS6265 Rev 4. This derating from 4 A (at TC = 25 °C) reflects thermal limitations of the DPAK package under elevated ambient conditions and requires appropriate PCB copper area and heatsinking to maintain safe junction temperature.

Does STD5N95K3 require an external gate resistor for stability in hard-switching applications?

Yes-a gate resistor (typically 4.7 Ω, per Figure 14 test circuit) is recommended to dampen ringing and control dV/dt during turn-on/turn-off. The device's 5.5 Ω intrinsic gate resistance and 19 nC total gate charge make external RG essential to limit peak gate current and prevent oscillation in high-frequency SMPS designs.

Can STD5N95K3 replace older STD5NK90Z devices in existing designs?

Yes, with validation: STD5N95K3 offers higher V(BR)DSS (950 V vs. 900 V), lower RDS(on) (3.5 Ω vs. 4.2 Ω), and improved diode recovery (Qrr reduced by ~25%). However, layout review is required due to differences in gate charge profile and avalanche energy distribution-especially in unclamped inductive loads.

Is the drain tab electrically isolated from the PCB copper pour in DPAK mounting?

No-the drain tab (Pin 2) is electrically connected to the internal drain structure and must be soldered directly to a dedicated high-voltage copper pour or heatsink. Electrical isolation requires insulating thermal pads or ceramic substrates; standard FR-4 mounting assumes drain-to-PCB connectivity for both thermal and circuit functionality.