STMicroelectronics STI17NF25

Overview

STI17NF25 from STMicroelectronics is an N-channel enhancement-mode Power MOSFET in I²PAK (TO-262) package, rated for 250 V V_DSS, <0.165 Ω R_DS(on) at V_GS = 10 V and 8.5 A, 17 A continuous drain current, and 90 W total power dissipation. It features low gate charge (29.5 nC), 100% avalanche tested operation, and exceptional dv/dt capability (10 V/ns), making it suitable as a primary switch in high-efficiency isolated DC-DC converters.

For engineers reviewing the STI17NF25 datasheet, STI17NF25 pinout, STI17NF25 application, or STI17NF25 equivalent, key selection criteria include its 250 V breakdown voltage, 0.14 Ω typical on-resistance, 17 A pulsed drain current, thermal resistance of 1.38 °C/W (junction-to-case), and STripFET™ II process optimization for reduced input capacitance and switching losses in hard-switched topologies.

Technical Context

This MOSFET employs ST's STripFET™ II vertical diffusion process to achieve low R_DS(on) and minimized gate charge (Q_g = 29.5 nC, Q_gd = 15.6 nC), enabling fast switching with reduced driver loss. Its 100% unclamped inductive avalanche rating (E_AS = 100 mJ) supports robust operation under transient overvoltage conditions without external snubbers.

The device exhibits strong dv/dt immunity (10 V/ns) and reverse recovery performance (t_rr = 157 ns at T_j = 25°C), critical for reliable operation in flyback and resonant converter primary-side switching where diode commutation stress occurs. Its SOA is defined up to 150°C junction temperature with derating factor 0.72 W/°C.

Key Specifications

Pinout & Package

STI17NF25 is housed in an I²PAK (TO-262) package with three leads: Gate (G), Drain (D), and Source (S). The package features a fully insulated plastic body, single-piece leadframe, and exposed drain tab for direct thermal coupling to heatsinks. Mounting hole accommodates M3 screw for mechanical fixation and thermal enhancement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel 250 V Power MOSFET applications.

Compared with STP17NF25, STI17NF25 offers identical electrical specs but superior SMT manufacturability and lower R_thj-amb on PCB; versus IRFP460, it delivers 48% lower R_DS(on) and 79% less gate charge-enabling higher efficiency and frequency in modern SMPS designs.

Availability

STI17NF25 is available at Aetrix Electronics and suitable for server power supplies, industrial AC-DC adapters, and telecom DC-DC bricks requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for STI17NF25 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 ST's STripFET™ Power MOSFET product line, engineered specifically for high-efficiency, high-reliability switching power conversion in isolated DC-DC, PFC, and offline SMPS applications.

FAQ

Is STI17NF25 suitable for gate-drive voltages below 10 V?

No. The device is characterized for R_DS(on) and switching parameters at V_GS = 10 V. At 5 V, R_DS(on) increases significantly (>0.3 Ω), raising conduction loss and thermal stress. It is not a logic-level MOSFET and requires a dedicated 10–15 V gate driver with sufficient peak current to charge 29.5 nC gate capacitance rapidly.

What is the maximum recommended PCB copper area for thermal relief when using STI17NF25 in I²PAK?

For optimal thermal performance, ST recommends mounting the I²PAK package on ≥1 inch² (645 mm²) of 2 oz copper on the primary side, with thermal vias connecting to internal/secondary ground planes. This achieves R_thj-amb ≈ 50 °C/W, allowing full 90 W dissipation at T_C = 25°C ambient with proper airflow.

Does STI17NF25 require a gate resistor for safe operation?

Yes. A gate resistor (typically 4.7–10 Ω) is required to dampen parasitic oscillation, control dV/dt during turn-on, and limit peak gate current. The datasheet specifies switching times (e.g., t_d(on) = 8.8 ns) with R_G = 4.7 Ω; omitting it risks overshoot, shoot-through, and gate oxide damage during fast transitions.

Can STI17NF25 replace STF17NF25 in a TO-220FP-based design?

No. Although electrically identical, STF17NF25 uses a TO-220FP (full-pack) package with insulated tab and different pin pitch (2.4 mm vs 5.15 mm for I²PAK). Mechanical interference, solder pad layout mismatch, and thermal interface differences make direct replacement impossible without PCB redesign and thermal revalidation.