Vishay General Semiconductor - Diodes Division FESF8AT-E3/45

Overview

FESF8AT-E3/45 from Vishay General Semiconductor is an ultrafast plastic rectifier diode in ITO-220AC package, rated for 50 V repetitive peak reverse voltage (V_RRM), 8.0 A average forward current (I_F(AV)), and 35 ns reverse recovery time (t_rr). It serves as a high-efficiency freewheeling or output rectifier in compact switching-mode power supplies operating at 100–500 kHz.

For engineers reviewing the FESF8AT-E3/45 datasheet, FESF8AT-E3/45 pinout, FESF8AT-E3/45 application, or FESF8AT-E3/45 equivalent, key selection criteria include its 35 ns t_rr, 0.95 V forward voltage at 8 A, 125 A surge rating, 150 °C max junction temperature, and ITO-220AC thermal performance with 1500 V isolation.

Technical Context

This device belongs to Vishay's FES(F,B)8xT family of ultrafast rectifiers optimized for high-frequency switching applications. Its glass-passivated junction ensures stable leakage (<10 µA at 25 °C) and robustness against moisture and thermal cycling, while the ITO-220AC package provides enhanced creepage and 1500 V terminal-to-heatsink isolation.

The FESF8AT-E3/45 operates with low switching losses due to its 35 ns recovery time and 0.95 V forward voltage at rated current, enabling high efficiency in DC-DC converters and PFC stages where fast turn-off and minimal reverse recovery charge are critical.

Key Specifications

Pinout & Package

Package: ITO-220AC - Insulated TO-220 variant with reinforced creepage distance and 1500 V isolation between leads and heatsink mounting surface. Matte tin-plated leads, RoHS-compliant, JESD201 Class 1A whisker tested.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultrafast rectifier applications.

Compared with STTH8R06DJF and MUR860E, the FESF8AT-E3/45 delivers best-in-class efficiency for 50 V, 8 A applications due to its 0.95 V V_F and 35 ns t_rr, while its ITO-220AC isolation enables safer, simpler heatsink integration than non-isolated alternatives.

Availability

FESF8AT-E3/45 is available at Aetrix Electronics and suitable for server VRMs, industrial DC-DC converters, and telecom AC-DC adapters requiring stable component supply, consistent parametric performance, and RoHS-compliant manufacturing.

Supply support for FESF8AT-E3/45 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

Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, MOSFETs, and optoelectronics with emphasis on reliability, efficiency, and application-specific optimization.

The FES(F,B)8xT series was designed specifically for high-frequency power conversion systems demanding low-loss, fast-recovery rectification in space- and thermally-constrained environments.

FAQ

What is the maximum junction temperature rating for the FESF8AT-E3/45?

The FESF8AT-E3/45 has a maximum junction temperature (T_J) rating of 150 °C. This specification allows reliable operation in high-ambient environments such as enclosed industrial power supplies or automotive infotainment units. Derating curves in the Vishay datasheet (Document 88600) define safe I_F(AV) limits versus case temperature, and thermal design must ensure T_J does not exceed 150 °C under worst-case load and ambient conditions. The FESF8AT-E3/45 achieves this with its 5.0 °C/W R_θJC and ITO-220AC isolation.

Is the FESF8AT-E3/45 suitable for use in automotive applications?

The FESF8AT-E3/45 is rated for operation from –55 °C to +150 °C and meets JESD201 Class 1A whisker testing, making it suitable for under-dash or engine-compartment-adjacent automotive power supplies where qualification to AEC-Q101 is not mandated. However, it is not AEC-Q101 qualified-unlike the HE3-suffix variants (e.g., FESF8AT-HE3). For safety-critical or certified automotive modules, engineers should select the AEC-Q101-qualified FESF8AT-HE3 instead of the FESF8AT-E3/45.

How does the ITO-220AC package of the FESF8AT-E3/45 differ from standard TO-220AC?

The ITO-220AC package of the FESF8AT-E3/45 features reinforced internal insulation between the leads and the metal tab, providing 1500 V AC isolation (1 min) from terminal to heatsink-unlike standard TO-220AC. This eliminates the need for insulating pads or shoulder washers when mounting to a live heatsink. The FESF8AT-E3/45 also uses matte tin-plated leads compliant with J-STD-002 and JESD22-B102, and its creepage distance exceeds that of TO-220AC, supporting higher safety standards in industrial and telecom equipment.

What is the reverse recovery time (t_rr) of the FESF8AT-E3/45, and how is it measured?

The FESF8AT-E3/45 has a typical reverse recovery time (t_rr) of 35 ns, measured under conditions of I_F = 0.5 A, I_R = 1.0 A, and I_rr = 0.25 A, per the Vishay datasheet (Document 88600). This ultrafast value reflects the diode's ability to transition rapidly from forward conduction to reverse blocking, minimizing switching losses and EMI generation in high-frequency converters. The FESF8AT-E3/45 achieves this via optimized carrier lifetime control in its glass-passivated silicon junction.

Can the FESF8AT-E3/45 be used as a direct replacement for the FES8AT-E3/45?

No-the FESF8AT-E3/45 and FES8AT-E3/45 are not interchangeable without layout review. While both share identical electrical ratings (50 V V_RRM, 8 A I_F(AV), 35 ns t_rr), they differ in package: FES8AT-E3/45 uses TO-220AC (non-isolated), whereas FESF8AT-E3/45 uses ITO-220AC (1500 V isolated). Mounting hole alignment and creepage distances differ; using FESF8AT-E3/45 in a TO-220AC footprint may compromise isolation or mechanical stability. Always verify mechanical fit and isolation requirements before substitution.