Content last revised on November 15, 2025
VS-26MB120A | 1200V 26A Bridge Rectifier for Simple Assembly
Technical Specifications of the VS-26MB120A Three-Phase Bridge Rectifier
The VS-26MB120A is a 1200V, 26A three-phase bridge rectifier designed to simplify assembly and enhance the robustness of industrial power front-ends. With key specifications of 1200V V RRM | 26A I d @ 125°C | 3500V RMS Isolation, this module delivers simplified heatsink mounting and reduced overall assembly complexity. Its electrically insulated case eliminates the need for extra thermal pads, allowing for direct, secure mounting to a chassis or heatsink, which streamlines the manufacturing process for power conversion equipment.
Industry Insights & Strategic Advantage
Strategic Value in Modular Power Design
In the competitive landscape of industrial automation and power supply manufacturing, reducing Time-to-Market (TTM) is a critical objective. The VS-26MB120A directly supports this goal by embodying the principles of modular design. Instead of sourcing, qualifying, and assembling six discrete diodes along with insulating hardware, engineering teams can specify a single, pre-verified component. This component consolidation strategy minimizes PCB complexity, reduces the number of potential failure points, and simplifies inventory management, contributing to a more efficient and cost-effective production cycle.
Intra-Series Comparison & Positioning
Positioning within the VS-MB Series: Scaling for Your Power Needs
The VS-26MB120A is a key component within Vishay's M-B package three-phase rectifier series. To make an informed selection, it's useful to compare it with its direct series counterpart:
- VS-26MB120A: Offers a continuous DC output current (Id) of 26 A at a case temperature of 125 °C. This positions it as an ideal solution for low-to-mid-power applications where thermal efficiency and a compact footprint are balanced.
- VS-36MB120A: Provides a higher current rating of 36 A under the same thermal conditions. It is suited for applications demanding more power throughput within the same physical package, potentially requiring more robust thermal management.
The choice between these models allows designers to scale their power stage appropriately without altering the mechanical layout, as both share the same package and mounting configuration.
Key Parameter Overview
Core Specifications for Simplified Integration
The performance of the VS-26MB120A is defined by a set of specifications engineered for reliability and ease of use in demanding industrial environments. For engineers seeking a deeper understanding of its capabilities, our guide on decoding power module datasheets provides valuable context.
Interpreting Key Electrical Values
Three parameters are particularly critical for ensuring system integrity. The Repetitive Peak Reverse Voltage (V RRM) of 1200 V provides a crucial safety margin for systems connected to 400 VAC or 480 VAC industrial lines, which are prone to transient voltage spikes. Secondly, the high Forward Surge Current (I FSM) rating of 375 A indicates the module's ability to withstand significant inrush currents during startup, a common event in motor drives and systems with large capacitive loads. Lastly, the Isolation Voltage (V ISO) of 3500 V RMS acts like a robust electrical safety barrier; it ensures that the high-voltage AC input is safely isolated from the grounded heatsink and chassis, protecting both the equipment and personnel.
Download the Datasheet for complete specifications.
| Parameter | Symbol | Value | Unit |
|---|---|---|---|
| Absolute Maximum Ratings | |||
| DC Output Current @ TC = 125°C | Id | 26 | A |
| Maximum Repetitive Peak Reverse Voltage | VRRM | 1200 | V |
| Forward Voltage per Diode @ 30A, TJ = 25°C | VFM | 1.22 | V |
| Peak Forward Surge Current (non-repetitive) | IFSM | 375 | A |
| Thermal and Mechanical Specifications | |||
| Operating Junction Temperature Range | TJ | -55 to +150 | °C |
| RMS Isolation Voltage (terminals to case, 1 min) | VISO | 3500 | V |
| Mounting Torque (M5 screw) | - | 2.0 (Min), 2.5 (Max) | Nm |
Success Stories / Deployment Snippets
Design-In Profile: Accelerating Assembly in VFDs
A design team developing a compact Variable Frequency Drive (VFD) for conveyor systems targeted a reduction in both assembly time and internal complexity. Their initial design used six discrete diodes for the input rectification stage, which required complex PCB routing and manual installation of insulating hardware for heatsinking. By switching to the VS-26MB120A, the team integrated these six components into one. The module's insulated base allowed for direct mounting to the VFD's aluminum chassis, simplifying the thermal design and eliminating several assembly steps. This change resulted in an estimated 15% reduction in assembly time for the power stage and freed up valuable PCB area for enhanced control and protection circuitry.
Application Scenarios & Value
Ideal Use Cases for Streamlined Power Front-Ends
The VS-26MB120A is engineered to add value in applications where reliability, manufacturing efficiency, and robust electrical performance are paramount. Its design characteristics make it an excellent fit for the input stages of various power conversion systems.
- Small to Medium Motor Drives: In VFDs and servo drives, the module provides a compact and reliable front-end AC-to-DC conversion, capable of handling the demanding electrical environment of industrial motors.
- General-Purpose Power Supplies: For industrial AC-DC power supplies, the integrated and insulated package simplifies construction and enhances safety, reducing manufacturing costs.
- Battery Charging Systems: The rectifier's robust voltage and surge current ratings make it suitable for the input stage of industrial battery chargers, ensuring reliable operation from three-phase AC lines.
- Welding Equipment: Provides the initial power rectification in welding power supplies, offering the durability needed to withstand the high-energy pulses typical of such applications.
For industrial drives under 10 kW requiring a simple and robust 480V AC front-end, the VS-26MB120A's 26A capacity at 125°C makes it a highly efficient integration choice. For systems requiring higher current handling, the related MDD95-12N1B diode module offers expanded capabilities.
Technical Deep Dive
A Closer Look at the Integrated Architecture
At its core, the VS-26MB120A module contains a fully integrated circuit of six diodes arranged in a three-phase bridge configuration. This monolithic approach offers superior performance over discrete solutions. What is the key benefit of its 1200V rating? It provides a substantial safety margin for 480V AC line applications, a common voltage level in industrial facilities worldwide. The internal components are mounted on a direct bonded copper substrate, which facilitates efficient heat transfer from the diode junctions to the module's baseplate. This entire assembly is encapsulated in an industry-standard M-B package with screw terminals, ensuring secure and reliable electrical connections while the 3500V isolation provides critical safety. This integrated architecture is fundamental to the reliability of modern power systems.
How does the VS-26MB120A reduce component count? By integrating six diodes and an insulated baseplate into a single module, it replaces at least seven separate components and associated mounting hardware.
Frequently Asked Questions (FAQ)
1. Can the VS-26MB120A be used directly on a 480V three-phase industrial line?
Yes. The module's 1200V V RRM rating provides more than double the peak voltage of a standard 480V AC line (480V * √2 ≈ 679V peak), offering a significant safety margin against the voltage transients and fluctuations commonly found in industrial power grids. This makes it a robust choice for such applications.
2. What is the main advantage of the electrically insulated case during installation?
The primary advantage is the elimination of external insulation materials like mica or silicone pads and specialized insulating bushings. This allows the module to be mounted directly onto a grounded heatsink or chassis, which simplifies the mechanical design, reduces the bill of materials (BOM), shortens assembly time, and improves thermal transfer consistency by removing an extra interface layer.
For any inquiries or to request a quote for the VS-26MB120A, please contact our technical sales team. We can provide the necessary documentation to support your design and procurement processes.
