STMicroelectronics STFW8N120K5

Overview

STFW8N120K5 from STMicroelectronics is a 1200 V, 1.65 Ω (typ), 6 A N-channel Power MOSFET in TO-3PF package, built on MDmesh K5 vertical structure for ultra-low gate charge (13.7 nC) and high avalanche ruggedness (415 mJ). It serves as a high-voltage switching device in industrial SMPS, HV DC-DC converters, and PFC stages where efficiency and reliability under repetitive unclamped inductive stress are critical.

For engineers reviewing the STFW8N120K5 datasheet, STFW8N120K5 pinout, STFW8N120K5 application, or STFW8N120K5 equivalent, key selection factors include its 3.5 kV insulation withstand voltage, 50 V/ns MOSFET dv/dt ruggedness, 100% avalanche tested rating, Zener-protected gate, and thermal resistance of 2.6 °C/W (junction-to-case).

Technical Context

This MOSFET employs ST's proprietary MDmesh K5 technology with an optimized vertical drift region to simultaneously reduce R_DS(on) and gate charge-achieving a FoM (R_DS(on) × Q_g) of ~22.5 Ω·nC. Its Zener-protected gate structure enables robust ±30 V gate drive tolerance without external clamping.

The device features a fast, soft-recovery body diode (t_rr = 327 ns at T_j = 25 °C; Q_rr = 3 µC) and is rated for unclamped inductive switching up to 1.7 A avalanche current. Safe operating area (SOA) is defined up to 10 ms at 25 °C with V_GS = 10 V, limited by R_DS(on) at high V_DS.

Key Specifications

Pinout & Package

TO-3PF package: metal-can, isolated tab, 3-terminal through-hole housing with internal heat spreader and creepage-optimized lead spacing. Mounting flange electrically connected to drain (D); no external insulator required when heatsink is grounded.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STW48N120K5 and IXTH30N120L2, STFW8N120K5 delivers optimal balance of gate drive simplicity (Zener-protected), thermal manageability (TO-3PF, 2.6 °C/W), and ruggedness (3.5 kV isolation, 100% avalanche test) for 6 A industrial switching where layout space and reliability outweigh raw current capacity.

Availability

STFW8N120K5 is available at Aetrix Electronics and suitable for industrial switch-mode power supplies, high-voltage DC-DC converters, and motor drive brake choppers requiring stable component supply, long-lifecycle assurance, and traceable sourcing.

Supply support for STFW8N120K5 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 management, analog, microcontrollers, and automotive ICs with ISO 9001 and IATF 16949 certified manufacturing.

This device belongs to ST's MDmesh K5 high-voltage Power MOSFET product line, engineered specifically for efficiency-critical 800–1200 V industrial power conversion systems demanding low FoM, avalanche robustness, and simplified gate drive.

FAQ

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

The STFW8N120K5 supports 3.5 A continuous drain current at T_C = 100 °C, as specified in Table 1 of DS12562 Rev 3. This derating reflects thermal limits of the TO-3PF package and ensures junction temperature remains within −55 to 150 °C range under sustained load.

Does this MOSFET require external gate protection?

No. The STFW8N120K5 integrates Zener protection on the gate oxide, enabling safe operation with ±30 V gate-source voltage without external clamping components. This eliminates the need for discrete TVS diodes in standard gate drive circuits.

Can it replace older STW11NK120Z devices in existing designs?

Yes, but with design review: STFW8N120K5 offers lower R_DS(on) (1.65 Ω vs 2.2 Ω) and Q_g (13.7 nC vs 45 nC), improving efficiency, yet shares identical TO-3PF footprint and pinout. Gate drive timing and snubber values may require adjustment due to faster switching.

What is the safe operating area (SOA) limitation at 600 V drain voltage?

At V_DS = 600 V and T_C = 25 °C, the SOA limits continuous current to approximately 4.2 A for DC operation (per Figure 1), constrained by R_DS(on)-based power dissipation. For pulse widths ≤100 µs, peak current can reach 12 A (I_DM) without exceeding thermal or avalanche limits.