STMicroelectronics STH15NB50FI

Overview

STH15NB50FI from STMicroelectronics is an N-channel 500 V, 10.5 A (T_c = 100 °C), 0.33 Ω R_DS(on) PowerMESH™ MOSFET in ISOWATT218 package, designed for high-speed switching in high-voltage DC-AC converters and welding equipment power stages.

For engineers reviewing the STH15NB50FI datasheet, STH15NB50FI pinout, STH15NB50FI application, or STH15NB50FI equivalent, key selection criteria include its 4000 V isolation rating, 150 °C max junction temperature, 850 mJ single-pulse avalanche energy, and low 27 nC gate-drain charge enabling efficient hard-switching at 250–400 V bus voltages.

Technical Context

This MOSFET employs ST's proprietary MESH OVERLAY™ process with strip layout and edge termination to achieve minimum R_DS(on)/area and exceptional dv/dt immunity (4 V/ns). Its 0.33 Ω typical on-resistance is specified at V_GS = 10 V and I_D = 7.5 A, with gate threshold voltage tightly distributed between 3–5 V.

The device integrates a robust body diode with 1.6 V forward voltage at 15 A and 680 ns reverse recovery time under 100 A/µs di/dt - critical for snubberless inductive turn-off in motor drives and UPS inverters.

Key Specifications

Pinout & Package

STH15NB50FI uses the ISOWATT218 package - a through-hole, insulated case variant of TO-247 with creepage/clearance optimized for high-voltage isolation. The package features three leads: Drain (pin 1), Gate (pin 2), Source (pin 3), with pin 1 electrically isolated from the metal tab.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STW15NB50 and IPP120N15N3G, STH15NB50FI uniquely combines 500 V rating, 4000 V isolation, and 0.33 Ω R_DS(on) in a single package - making it irreplaceable in space-constrained, safety-critical high-voltage inverters where creepage and thermal management must coexist.

Availability

STH15NB50FI is available at Aetrix Electronics and suitable for welding equipment inverters, uninterruptible power supplies (UPS), and industrial motor drives requiring stable component supply across extended production lifecycles.

Supply support for STH15NB50FI 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, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and power applications.

The PowerMESH™ MOSFET product line targets high-reliability, high-efficiency power conversion - specifically engineered for ruggedized switching in welding, UPS, and motor control systems where avalanche robustness and isolation integrity are non-negotiable.

FAQ

Is STH15NB50FI pin-compatible with STW15NB50?

No - STH15NB50FI uses the ISOWATT218 package with insulated case and 3-pin layout (Drain-Gate-Source), while STW15NB50 uses standard TO-247 with electrically connected tab. Mechanical mounting, thermal path, and isolation requirements differ fundamentally; PCB redesign is required for substitution.

What is the maximum recommended gate resistor value for reliable switching?

For 400 V V_DD, 15 A I_D, and RG = 4.7 Ω (per datasheet test condition), the gate resistor should not exceed 10 Ω to maintain <35 ns fall time and avoid excessive Q_gd-driven Miller plateau duration. Higher values increase switching losses and risk shoot-through in bridge configurations.

Does STH15NB50FI require a negative gate turn-off voltage?

No - the ±30 V gate rating provides margin, but the device operates reliably with 0 V to +10 V gate drive. Negative turn-off (e.g., –5 V) is optional and used only in noisy environments to improve noise immunity; it does not affect R_DS(on) or switching speed.

Can STH15NB50FI replace obsolete STP15NB50 in existing designs?

No - STP15NB50 is TO-220 packaged (R_thj-case ≈ 2.5 °C/W) with different pinout and no isolation. STH15NB50FI's ISOWATT218 footprint, 4000 V isolation, and 1.56 °C/W thermal resistance require mechanical, thermal, and safety revalidation before integration.