Vishay General Semiconductor - Diodes Division GBU8B-M3/51

Overview

GBU8B-M3/51 from Vishay General Semiconductor is a glass passivated single-phase bridge rectifier rated for 100 V maximum repetitive peak reverse voltage (VRRM), 8.0 A average forward rectified output current at TC = 60 °C, and 200 A non-repetitive peak forward surge current (IFSM). It features 1.0 V forward voltage drop at 8.0 A, 5 μA reverse leakage current at 25 °C, and is packaged in the GBU case with matte tin-plated leads for PCB mounting in AC/DC power supplies.

For engineers reviewing the GBU8B-M3/51 datasheet, GBU8B-M3/51 pinout, GBU8B-M3/51 application, or GBU8B-M3/51 equivalent, key selection factors include its 100 V VRRM rating, 8.0 A IF(AV) thermal derating behavior, 4.0 °C/W junction-to-case thermal resistance, and halogen-free RoHS-compliant M3 suffix construction suitable for industrial and consumer power conversion designs.

Technical Context

The GBU8B-M3/51 implements a standard full-wave bridge configuration with four silicon diodes arranged in a single-phase in-line package. Its glass passivation ensures stable reverse characteristics and high dielectric strength (1500 VRMS case isolation), supporting reliable operation under transient overvoltage conditions in unregulated AC line inputs.

Designed for PCB mounting with 0.5" × 0.5" (12 mm × 12 mm) copper pads and 9.5 mm lead length, it delivers 3.9 A average forward current at TA = 40 °C in free-air conditions and supports soldering up to 275 °C for 10 s per JESD 22-B106, enabling compatibility with standard reflow and wave-solder processes.

Key Specifications

Pinout & Package

Package: GBU case - molded plastic housing with in-line terminal configuration, UL 94 V-0 flammability rating, 0.860–0.880 inch (21.8–22.3 mm) body length, 0.190–0.210 inch (4.83–5.33 mm) width, polarity marked on body with beveled corner indicating positive output lead.

Key Features

Applications

Equivalent & Alternatives

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

Compared with GBU8B-M3/51, GBU8B-E3/51 offers identical performance with conventional RoHS compliance but lacks halogen-free status, while GBU8K-M3/51 provides eightfold higher reverse voltage rating at the expense of unnecessary overhead for 100 V applications-making GBU8B-M3/51 the optimal balance of rating, thermal efficiency, and regulatory compliance for 120 VAC systems.

Availability

GBU8B-M3/51 is available at Aetrix Electronics and suitable for monitor power supplies, printer AC/DC adapters, and home appliance control boards requiring stable component supply, halogen-free compliance, and UL-recognized reliability.

Supply support for GBU8B-M3/51 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, power efficiency, and industrial-grade qualification.

The GBU series was developed for high-current, high-surge AC/DC bridge rectification in space-constrained consumer and industrial power supplies, prioritizing thermal performance, safety certification, and manufacturability on standard PCB assembly lines.

FAQ

What is the maximum operating junction temperature for GBU8B-M3/51?

The GBU8B-M3/51 has a maximum operating junction temperature (TJ max.) of +150 °C, as specified in the Vishay datasheet Document Number 88616. This rating allows sustained operation in thermally demanding environments such as enclosed power supplies or high-ambient-temperature appliances. Derating curves show usable output current drops to 3.9 A at TA = 40 °C in free air, confirming thermal design must account for both conduction and ambient conditions to keep GBU8B-M3/51 within its 150 °C limit.

Does GBU8B-M3/51 require a heatsink in typical applications?

GBU8B-M3/51 does not require a heatsink when operating at ≤3.9 A average current in free air (TA = 40 °C), per datasheet condition (2). However, at its full 8.0 A rating, it must be mounted on an aluminum plate heatsink (condition 1) to maintain TC ≤ 60 °C. The 4.0 °C/W junction-to-case thermal resistance means even modest power dissipation (~8 W at full load) necessitates effective heat transfer-so PCB copper pads (12 mm × 12 mm) or bolt-down heatsinks are recommended for >5 A continuous use of GBU8B-M3/51.

What does the "M3" suffix mean in GBU8B-M3/51?

The "M3" suffix in GBU8B-M3/51 indicates halogen-free, RoHS-compliant construction meeting JEDEC J-STD-208 and IEC 61249-2-21 requirements. Unlike the E3 variant, M3 uses non-brominated flame retardants in the molding compound while retaining UL 94 V-0 flammability rating and passing JESD 201 Class 1A whisker testing. This makes GBU8B-M3/51 suitable for eco-conscious designs targeting EU markets or sustainability certifications where halogen content is restricted.

Can GBU8B-M3/51 be used in place of GBU8A-M3/51?

Yes, GBU8B-M3/51 can replace GBU8A-M3/51 in most applications because both share identical package (GBU), thermal specs (RθJC = 4.0 °C/W), surge rating (200 A IFSM), and forward voltage (1.0 V at 8.0 A), differing only in maximum repetitive peak reverse voltage: GBU8A-M3/51 is rated for 50 V, while GBU8B-M3/51 is rated for 100 V. Therefore, GBU8B-M3/51 offers enhanced margin for 100–120 VAC inputs and is backward compatible where 50 V was previously sufficient-no layout or thermal changes are needed.

Is GBU8B-M3/51 suitable for high-frequency switching applications?

GBU8B-M3/51 is not optimized for high-frequency switching applications above 20 kHz due to its relatively high junction capacitance (68 pF per diode at 4 V, 1 MHz) and soft recovery characteristics inherent to standard silicon rectifiers. It is engineered for 50/60 Hz line-frequency rectification in AC/DC power supplies. For high-frequency PFC or resonant topologies, fast recovery or ultrafast diodes (e.g., VS-GBU8K-M3/51 used with snubbers) are preferred-GBU8B-M3/51 remains appropriate for primary-side rectification in conventional offline SMPS where switching occurs downstream.