STMicroelectronics STF34N65M5

Overview

STF34N65M5 from STMicroelectronics is an N-channel 650 V, 28 A Power MOSFET in TO-220FP package, fabricated with MDmesh M5 vertical process technology. It delivers 90 mΩ typical R_DS(on), 15 V/ns diode recovery dv/dt capability, and 50 V/ns MOSFET dv/dt ruggedness-enabling high-efficiency switching in offline SMPS and PFC stages.

For engineers reviewing the STF34N65M5 datasheet, STF34N65M5 pinout, STF34N65M5 application, or STF34N65M5 equivalent, key selection criteria include its 650 V V_DSS, 100% avalanche-tested robustness, low C_oss (75 pF), fast switching (t_r(v) = 8.7 ns), and integrated source-drain diode with 350 ns t_rr at 25 °C.

Technical Context

This device uses ST's MDmesh M5 process to achieve ultra-low on-resistance while maintaining high voltage blocking. Its optimized charge distribution enables superior dv/dt immunity (50 V/ns) and reduced E_oss (63 µJ at 500 V), critical for hard-switched and ZVS topologies.

The integrated body diode features low Q_rr (5.6 µC typ.) and soft recovery behavior, minimizing switching losses and EMI in bridge-leg configurations. Thermal resistance R_thJC is 3.57 °C/W, supporting 35 W continuous dissipation at T_C = 25 °C.

Key Specifications

Pinout & Package

Package: TO-220FP (Type B), insulated case, vertical mounting with heat sink contact via tabless drain connection. Pin 1 = Gate, Pin 2 = Drain, Pin 3 = Source.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IPP65R099C7 and STW34N65M5, STF34N65M5 uniquely combines 2.5 kV insulation, 50 V/ns dv/dt ruggedness, and TO-220FP form factor-making it optimal for space-constrained, safety-critical AC-DC systems where mounting simplicity and transient immunity are prioritized over ultimate thermal performance.

Availability

STF34N65M5 is available at Aetrix Electronics and suitable for server PSUs, industrial PFC modules, solar microinverters, and EV onboard chargers requiring stable component supply across multi-year production cycles.

Supply support for STF34N65M5 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

STF34N65M5 belongs to the MDmesh™ M5 high-voltage Power MOSFET product line, engineered specifically for high-efficiency, high-reliability offline power conversion in 650 V applications.

FAQ

What is the maximum safe operating temperature for STF34N65M5?

The absolute maximum junction temperature is 150 °C. Operation above this limit risks permanent degradation of the silicon die and packaging integrity. Derating is required above T_C = 100 °C, where continuous current drops to 17.7 A. Thermal design must ensure R_thJC + R_thCS + R_thSA keeps T_J ≤ 150 °C under worst-case ambient and load conditions.

Does STF34N65M5 require a gate resistor for reliable operation?

Yes-a gate resistor (typically 4.7 Ω to 10 Ω) is required to control dV/dt during turn-on and prevent oscillation. The datasheet specifies switching times using RG = 4.7 Ω. Lower values increase peak gate current and risk ringing; higher values slow switching and raise losses. Layout parasitics must also be minimized to avoid unintended LC resonance.

Can STF34N65M5 replace older STF24NM50 in existing designs?

No-STF24NM50 is a 500 V, 24 A device with different R_DS(on) (140 mΩ), gate charge (45 nC), and thermal characteristics. While pin-compatible, STF34N65M5 has higher V_DSS, lower R_DS(on), and improved dv/dt ruggedness, but gate drive timing and SOA margins must be re-validated due to differences in Q_gd, C_iss, and avalanche energy rating.

Is the body diode suitable for synchronous rectification?

No-the integrated body diode is not optimized for synchronous rectification. Its Q_rr (5.6 µC) and V_SD (1.5 V) are significantly higher than dedicated SR MOSFETs. For synchronous rectification, use a separate low-V_F, low-Q_rr N-channel device driven by a dedicated controller; STF34N65M5 should remain in the primary-side switching role.