Vishay General Semiconductor - Diodes Division FESF8GT-E3/45

Overview

FESF8GT-E3/45 from Vishay General Semiconductor is an ultrafast plastic rectifier diode in ITO-220AC package, rated for 400 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 switching-mode power supplies operating at 100–500 kHz.

For engineers reviewing the FESF8GT-E3/45 datasheet, FESF8GT-E3/45 pinout, FESF8GT-E3/45 application, or FESF8GT-E3/45 equivalent, key selection criteria include its 35 ns t_rr, 1.30 V forward voltage at 8.0 A, 125 A non-repetitive surge rating, TO-220 variant thermal resistance (R_θJC = 5.0 °C/W), and RoHS-compliant matte tin-plated leads solderable per J-STD-002.

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 performance up to 100 °C, while the ITO-220AC package provides electrical isolation (1500 V_AC) between terminals and heatsink - critical for secondary-side rectification in isolated DC-DC converters.

The FESF8GT-E3/45 exhibits low switching losses due to its 35 ns t_rr and 85 pF junction capacitance at 4.0 V/1 MHz, enabling efficient operation in synchronous rectifier auxiliary paths and high-density AC-DC adapters where EMI and thermal management are constrained.

Key Specifications

Pinout & Package

Package: ITO-220AC - insulated TO-220 variant with 1500 V_AC isolation between leads and heatsink mounting surface; matte tin-plated leads compliant with J-STD-002; 1.85 g unit weight.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STTH8R04DJF and MUR840E, the FESF8GT-E3/45 uniquely combines 35 ns t_rr, 1500 V_AC isolation, and JESD201 Class 1A qualification - making it the only option among the three suitable for space-constrained, isolated, high-frequency industrial power supplies requiring long-term whisker-free reliability.

Availability

FESF8GT-E3/45 is available at Aetrix Electronics and suitable for server power supplies, industrial DC-DC converters, and high-frequency inverters requiring stable component supply, consistent parametric performance across production lots, and long-term lifecycle support.

Supply support for FESF8GT-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 high-reliability, high-efficiency power components.

The FES(F,B)8xT series was engineered specifically for high-frequency switching power conversion, targeting applications demanding ultrafast recovery, low leakage, and robust surge capability in compact insulated packages.

FAQ

What is the maximum junction temperature rating for the FESF8GT-E3/45?

The FESF8GT-E3/45 has a maximum junction temperature (T_J) rating of 150 °C, as specified in the Vishay datasheet Document Number 88600. This allows reliable operation in industrial environments with ambient temperatures up to 70 °C when mounted on a properly sized heatsink. The FESF8GT-E3/45 maintains stable electrical characteristics-including reverse leakage and forward voltage-within this thermal envelope, supporting continuous-duty applications such as server PSUs and motor drive auxiliary supplies.

Does the FESF8GT-E3/45 have electrical isolation between its leads and heatsink?

Yes, the FESF8GT-E3/45 uses the ITO-220AC package, which provides 1500 V_AC isolation between terminals and heatsink for one minute, as confirmed in the Mechanical Data section of the Vishay datasheet. This eliminates the need for insulating pads or sleeves in isolated secondary-side layouts. The FESF8GT-E3/45 achieves this via molded insulation between the die attach paddle and lead frame, making it distinct from standard TO-220AC variants.

What is the reverse recovery time (t_rr) of the FESF8GT-E3/45 and how is it measured?

The FESF8GT-E3/45 has a maximum 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 Electrical Characteristics table in Vishay Document Number 88600. This value reflects the time required for minority carriers to clear after forward conduction, directly impacting switching loss in high-frequency topologies. The FESF8GT-E3/45's 35 ns t_rr is verified across production lots and supports efficient operation up to 500 kHz.

Is the FESF8GT-E3/45 RoHS-compliant and what plating is used on its leads?

Yes, the FESF8GT-E3/45 is RoHS-compliant per Directive 2011/65/EU and features matte tin-plated leads that meet J-STD-002 solderability requirements. The "E3" suffix denotes consumer-grade qualification, including JESD201 Class 1A whisker testing. This plating ensures reliable wetting during wave and reflow soldering without voiding or dewetting, and the FESF8GT-E3/45 maintains solder joint integrity under thermal cycling from −55 °C to +150 °C.

How does the thermal resistance of the FESF8GT-E3/45 compare to other packages in the FES8xT family?

The FESF8GT-E3/45 (ITO-220AC) has a typical junction-to-case thermal resistance (R_θJC) of 5.0 °C/W, higher than the 2.2 °C/W of TO-220AC (FES8GT-E3/45) and TO-263AB (FESB8GT-E3/45) variants due to added insulation layers. This means the FESF8GT-E3/45 requires ~2.3× larger heatsink area than the TO-220AC version for equivalent temperature rise. Designers must account for this in thermal modeling, especially in compact 1U server PSUs where airflow is limited.