STMicroelectronics STFI31N65M5

Overview

STFI31N65M5 from STMicroelectronics is an N-channel 650 V, 22 A Power MOSFET based on MDmesh M5 vertical process technology in TO-247 package. It delivers 0.124 Ω R_DS(on) at V_GS = 10 V, 150 W total power dissipation at T_C = 25 °C, and 45 nC total gate charge - optimized for high-efficiency PFC and hard-switched SMPS in industrial power supplies.

For engineers reviewing the STFI31N65M5 datasheet, STFI31N65M5 pinout, STFI31N65M5 application, or STFI31N65M5 equivalent, key selection criteria include avalanche ruggedness (410 mJ E_AS), fast diode recovery (336 ns t_rr), low C_oss (45 pF), and 150 °C maximum junction temperature capability.

Technical Context

This device implements a high-voltage silicon-based planar-gate superjunction structure with optimized charge balance, enabling low conduction loss without sacrificing switching speed. Its 650 V V_(BR)DSS rating and 50 V/ns dv/dt ruggedness support operation in 400 V DC bus systems with margin against transient overvoltage.

The integrated body diode exhibits 1.5 V forward voltage at 22 A and 336 ns reverse recovery time at 100 A/μs di/dt - critical for ZVS/ZCS resonant topologies and reducing commutation losses in bridge configurations.

Key Specifications

Pinout & Package

TO-247 package: isolated tab (drain-connected), 3-pin through-hole configuration with standard lead spacing. Thermal path optimized via copper tab directly bonded to die backside.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STW31N65M5, STFI31N65M5 offers guaranteed 2500 V RMS insulation to heatsink - critical for medical and safety-certified power supplies. Versus IPW65R090CFD7, it trades 7% higher R_DS(on) for 64% higher E_AS and proven diode softness in high-di/dt conditions.

Availability

STFI31N65M5 is available at Aetrix Electronics and suitable for industrial switch-mode power supplies, server rectifiers, motor drive inverters, and renewable energy converters requiring stable component supply across multi-year production cycles.

Supply support for STFI31N65M5 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

This device belongs to the MDmesh™ M5 high-voltage Power MOSFET product line, engineered specifically for high-efficiency, high-reliability AC-DC and DC-DC conversion in demanding industrial and infrastructure applications.

FAQ

What is the maximum gate-source voltage rating for STFI31N65M5?

The absolute maximum V_GS is ±25 V, with recommended operating range of –10 V to +15 V. Exceeding ±25 V risks permanent gate oxide damage. Gate drive circuits must include clamping (e.g., 15 V Zener) and series resistance (≥10 Ω) to limit peak current during fast transitions.

Does STFI31N65M5 require a heatsink in typical 22 A operation?

Yes - at 22 A continuous drain current and 0.148 Ω R_DS(on), conduction loss reaches ~7.2 W. With 0.83 °C/W junction-to-case thermal resistance, case temperature would exceed 150 °C without heatsinking. A 1.5 °C/W heatsink maintains T_j ≤ 125 °C at 25 °C ambient.

How does the body diode performance compare to discrete Schottky diodes?

Its body diode has 1.5 V V_SD at 22 A and 336 ns t_rr, outperforming standard 650 V Si diodes but not matching 1.2 V Schottky forward drop. However, its integrated co-packaging eliminates parasitic inductance, making it preferable in high-di/dt synchronous rectification where discrete Schottky placement introduces layout-induced ringing.

Is STFI31N65M5 suitable for use in automotive under-hood applications?

No - while rated for –55 °C to +150 °C junction temperature, it lacks AEC-Q101 qualification, PPAP documentation, and automotive-specific reliability testing (e.g., HTGB, HTRB). For automotive 12 V/48 V DC-DC or OBC applications, ST recommends AEC-Q101-qualified variants like STL31N65M5 in DPAK.