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Home > Products > Discrete Semiconductor Products > Diodes > Rectifiers > Single Diodes

Vishay General Semiconductor - Diodes Division FESB8GT-E3/81

Name: FESB8GT-E3/81
Brand: Vishay General Semiconductor - Diodes Division
SKU: FESB8GT-E3/81
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: FESB8GT-E3/81

Manufacturer:: Vishay General Semiconductor - Diodes Division

Category:: Single Diodes

Package:: TO-263-3, D2PAK (2 Leads + Tab), TO-263AB

Datasheet:: FESB8GT-E3/81.pdf

Description:: DIODE GEN PURP 400V 8A TO263AB

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Product details

Overview

FESB8GT-E3/81 from Vishay General Semiconductor is an ultrafast plastic rectifier diode in TO-263AB (D²PAK) 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 FESB8GT-E3/81 datasheet, FESB8GT-E3/81 pinout, FESB8GT-E3/81 application, or FESB8GT-E3/81 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-263AB thermal resistance (R_θJC = 2.2 °C/W), and RoHS-compliant, MSL Level 1 construction.

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 enables stable operation up to 150 °C junction temperature, while low leakage (<10 µA at 25 °C) and low junction capacitance (50 pF at 4.0 V) support clean turn-off in hard-switched topologies.

The FESB8GT-E3/81 uses a planar epitaxial structure with controlled carrier lifetime to achieve consistent 35 ns t_rr under standardized test conditions (I_F = 0.5 A, I_R = 1.0 A, I_rr = 0.25 A). Its TO-263AB package provides enhanced thermal performance over TO-220AC variants, with direct heatsink mounting via the exposed cathode tab (Pin 2).

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	400 V - Maximum repetitive blocking voltage; supports 280 V RMS input in offline SMPS designs.
I_F(AV)	8.0 A at T_C = 100 °C - Continuous DC output current capability with adequate heatsinking.
t_rr	35 ns - Enables efficient operation in 100–500 kHz converters with minimal switching loss.
V_F	1.30 V at 8.0 A - Low conduction loss improves system efficiency vs. standard fast recovery diodes.
I_FSM	125 A - Withstands 8.3 ms half-sine surge; suitable for inrush and transient overload conditions.
R_θJC	2.2 °C/W - Enables compact thermal design; ΔT = 17.6 °C rise at 8 A continuous conduction.
Junction Temp	−55 °C to +150 °C - Supports industrial and extended-temperature power supply operation.

Pinout & Package

Package: TO-263AB (D²PAK), surface-mount, with isolated anode (Pin 1) and electrically connected cathode tab (Pin 2 / K). Mounting requires solder reflow per J-STD-020 MSL Level 1 (peak 245 °C).

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Anode	Input terminal for forward current; connects to switching node or transformer secondary.
Pin 2 / K (Tab)	Cathode	Output terminal and thermal path; must be soldered to PCB copper pour or heatsink for R_θJC = 2.2 °C/W.

Key Features

Feature	Design Value
Glass passivated junction	Ensures long-term reliability and stable t_rr/V_F across temperature and life cycle.
Ultrafast 35 ns recovery	Reduces switching losses and EMI generation in high-frequency DC-DC and PFC stages.
Low 1.30 V forward drop	Lowers conduction loss by ~15% vs. comparable 400 V fast recovery diodes at 8 A.
TO-263AB thermal performance	R_θJC = 2.2 °C/W enables higher power density than TO-220AC (R_θJC = 5.0 °C/W).
RoHS-compliant & MSL Level 1	Supports lead-free reflow assembly without moisture sensitivity concerns.

Applications

Server PSU Output Rectification	Industrial DC-DC Converter Freewheeling
Use Scenario: Secondary-side synchronous rectification replacement in 12 V/48 V server power supplies operating at 300 kHz. IC Role / Device Role / Timing Role: Ultrafast freewheeling diode providing low-loss current path during high-side switch off-time. Use Value: 35 ns t_rr minimizes reverse recovery charge (Q_rr), reducing voltage spikes and MOSFET stress in LLC resonant converters.	Use Scenario: Input-stage rectification in 24 V industrial DC-DC modules with wide ambient temperature range (−40 °C to +85 °C). IC Role / Device Role / Timing Role: High-current output rectifier handling 8 A continuous load with 125 A surge tolerance. Use Value: 150 °C max junction temperature and low 10 µA leakage at 100 °C ensure stable operation in sealed enclosures.
Telecom Power Brick Snubber Diode	Motor Drive Inverter Freewheeling
Use Scenario: Clamp/snubber diode in telecom 48 V power bricks using active clamp forward topology. IC Role / Device Role / Timing Role: Fast-recovery path for transformer reset energy with precise t_rr control. Use Value: Consistent 35 ns t_rr across production lot ensures predictable clamp timing and reduced voltage overshoot.	Use Scenario: Freewheeling path in 3-phase BLDC motor drive inverters with 10–20 kHz PWM switching. IC Role / Device Role / Timing Role: Bidirectional current recirculation diode across each phase leg's low-side MOSFET. Use Value: Low 50 pF junction capacitance limits displacement current during high dv/dt commutation events.

Server PSU Output Rectification

Industrial DC-DC Converter Freewheeling

Use Scenario: Secondary-side synchronous rectification replacement in 12 V/48 V server power supplies operating at 300 kHz.

IC Role / Device Role / Timing Role: Ultrafast freewheeling diode providing low-loss current path during high-side switch off-time.

Use Value: 35 ns t_rr minimizes reverse recovery charge (Q_rr), reducing voltage spikes and MOSFET stress in LLC resonant converters.

Use Scenario: Input-stage rectification in 24 V industrial DC-DC modules with wide ambient temperature range (−40 °C to +85 °C).

IC Role / Device Role / Timing Role: High-current output rectifier handling 8 A continuous load with 125 A surge tolerance.

Use Value: 150 °C max junction temperature and low 10 µA leakage at 100 °C ensure stable operation in sealed enclosures.

Telecom Power Brick Snubber Diode

Motor Drive Inverter Freewheeling

Use Scenario: Clamp/snubber diode in telecom 48 V power bricks using active clamp forward topology.

IC Role / Device Role / Timing Role: Fast-recovery path for transformer reset energy with precise t_rr control.

Use Value: Consistent 35 ns t_rr across production lot ensures predictable clamp timing and reduced voltage overshoot.

Use Scenario: Freewheeling path in 3-phase BLDC motor drive inverters with 10–20 kHz PWM switching.

IC Role / Device Role / Timing Role: Bidirectional current recirculation diode across each phase leg's low-side MOSFET.

Use Value: Low 50 pF junction capacitance limits displacement current during high dv/dt commutation events.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STTH8R04DJF	Same V_RRM (400 V), I_F(AV) (8 A), but t_rr = 45 ns; TO-263AB package; VF = 1.35 V.	Slightly higher switching loss in >250 kHz designs due to longer t_rr.	Preferred where ST's automotive qualification (AEC-Q101) is required.
ON Semi MUR840CT	400 V, 8 A, but dual common-cathode configuration in TO-220AC; t_rr = 50 ns; VF = 1.30 V.	Requires two devices for single-diode function; higher R_θJC (5.0 °C/W) limits power density.	Selected when dual-diode layout or through-hole assembly is mandated.

Compared with STTH8R04DJF and MUR840CT, the FESB8GT-E3/81 delivers superior high-frequency efficiency via its 35 ns t_rr and lower thermal resistance, making it optimal for space-constrained, high-switching-frequency power supplies where thermal management and EMI reduction are critical.

Availability

FESB8GT-E3/81 is available at Aetrix Electronics and suitable for server power supplies, industrial DC-DC converters, and telecom power bricks requiring stable component supply, RoHS compliance, and MSL Level 1 manufacturability.

Supply support for FESB8GT-E3/81 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 ruggedness.

The FES(F,B)8xT series was engineered specifically for high-frequency switching power conversion, targeting reduced conduction and switching losses in modern SMPS, PFC, and inverter applications.

FAQ

What is the maximum junction temperature rating for the FESB8GT-E3/81?

The FESB8GT-E3/81 has a maximum junction temperature (T_J) of +150 °C, verified per Vishay Document Number 88600. This rating allows reliable operation in thermally demanding environments such as enclosed industrial power supplies or high-density server PSUs. Derating curves in the FESB8GT-E3/81 datasheet define safe I_F(AV) limits above 100 °C case temperature.

Is the FESB8GT-E3/81 suitable for lead-free reflow soldering?

Yes, the FESB8GT-E3/81 is qualified for lead-free reflow per J-STD-020 MSL Level 1, with a maximum peak temperature of 245 °C. Its matte tin-plated leads meet J-STD-002 and JESD22-B102 solderability standards. The "E3" suffix confirms consumer-grade qualification including JESD201 Class 1A whisker testing.

How does the FESB8GT-E3/81 differ from the FES8GT-E3/45 variant?

The FESB8GT-E3/81 and FES8GT-E3/45 share identical electrical specifications (V_RRM = 400 V, t_rr = 35 ns, V_F = 1.30 V), but differ in package and packaging format: FESB8GT-E3/81 is in TO-263AB (D²PAK) and supplied in tape-and-reel (800/reel), whereas FES8GT-E3/45 is in TO-220AC and supplied in tube (50/tube). Thermal resistance also differs: R_θJC = 2.2 °C/W (FESB8GT-E3/81) vs. 5.0 °C/W (FES8GT-E3/45).

What is the reverse leakage current specification for the FESB8GT-E3/81 at 100 °C?

Per the FESB8GT-E3/81 datasheet (Document 88600), the maximum DC reverse current (I_R) at rated V_DC = 400 V and T_C = 100 °C is 500 µA. At 25 °C, the limit is 10 µA. These values reflect typical silicon behavior for ultrafast rectifiers and are critical for standby power loss calculations in high-efficiency designs.

Does the FESB8GT-E3/81 have isolation between terminals and heatsink?

No - the FESB8GT-E3/81 in TO-263AB package does not provide electrical isolation between the cathode tab (Pin 2/K) and heatsink. The metal tab is electrically connected to the cathode. For isolated mounting, external insulating hardware (e.g., mica washer + shoulder washer) must be used. In contrast, the ITO-220AC variant (e.g., FESF8GT-E3/45) offers 1500 V_AC isolation between terminals and heatsink.

FESB8GT-E3/81 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay General Semiconductor - Diodes Division

Series:: -

Package/Case:: TO-263-3, D2PAK (2 Leads + Tab), TO-263AB

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Technology:: Standard

Voltage - DC Reverse (Vr) (Max):: 400 V

Current - Average Rectified (Io):: 8A

Voltage - Forward (Vf) (Max) @ If:: 1.3 V @ 8 A

Speed:: Fast Recovery =< 500ns, > 200mA (Io)

Reverse Recovery Time (trr):: 50 ns

Current - Reverse Leakage @ Vr:: 10 µA @ 400 V

Capacitance @ Vr, F:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: TO-263AB (D2PAK)

Operating Temperature - Junction:: -55°C ~ 150°C

FESB8GT-E3/81 FAQ

1.How can I place an order for FESB8GT-E3/81 through Aetrix?

Please submit a Request for Quotation (RFQ) for FESB8GT-E3/81 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for FESB8GT-E3/81 reliable?

The price and inventory of FESB8GT-E3/81 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FESB8GT-E3/81 is usually 5 days.

3.What payment methods are accepted for FESB8GT-E3/81?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FESB8GT-E3/81 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FESB8GT-E3/81?

FESB8GT-E3/81 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FESB8GT-E3/81 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for FESB8GT-E3/81?

For technical support, including FESB8GT-E3/81 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FESB8GT-E3/81 requirements.

6.How does Aetrix verify that FESB8GT-E3/81 is sourced from the original manufacturer or authorized distributors?

All FESB8GT-E3/81 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that FESB8GT-E3/81 meets industry standards.

7.What is the process for return or replacement of FESB8GT-E3/81?

All FESB8GT-E3/81 units undergo pre-shipment inspection (PSI). If there is an issue with FESB8GT-E3/81, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The FESB8GT-E3/81 part is unused and in its original packaging.

Return procedure for FESB8GT-E3/81:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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