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Home > Products > Discrete Semiconductor Products > Diodes > Bridge Rectifiers

Diodes Incorporated MB256

Name: MB256
Brand: Diodes Incorporated
SKU: MB256
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MB256

Manufacturer:: Diodes Incorporated

Category:: Bridge Rectifiers

Package:: 4-Square, MB

Datasheet:: MB256.pdf

Description:: BRIDGE RECT 1PHASE 600V 25A MB

Quantity:: RFQ Add To RFQ list

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Inventory:2,263

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Product details

Overview

MB256 from Diodes Incorporated is a high-current silicon bridge rectifier with 600 V maximum recurrent peak reverse voltage, 25 A average rectified output current at TC = 55°C, and 1.1 V typical forward voltage drop at 12.5 A. It features solderable universal terminals (0.25" Faston), UL 94V-0 metal case, and is designed for industrial AC/DC power conversion in switch-mode power supplies and motor drive front-ends.

For engineers reviewing the MB256 datasheet, MB256 pinout, MB256 application, or MB256 equivalent, key selection criteria include thermal resistance (R_JC = 2.5 °C/W), I²t fusing rating (373 A²s), RoHS-compliant lead-free finish (date code 0514+), and bolt-down mounting requirement with thermal compound for heat-sink coupling.

Technical Context

This single-phase full-wave bridge rectifier integrates four high-conductivity silicon diodes in a common anode–common cathode configuration. Its metal case provides direct thermal conduction to external heat-sinks, and the 0.25" Faston terminals support snap-on, solder, or PCB-mounting-enabling flexible integration into high-power industrial power stages.

Rated for operation from –55°C to +150°C, it delivers stable DC output under 60 Hz resistive or inductive loads. The device's low R_JC and high I_FSM (300 A, 8.3 ms half-sine) support surge-tolerant designs in line-powered equipment where transient immunity and thermal reliability are critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	600 V - Maximum repetitive reverse blocking capability per diode leg; defines safe AC input voltage range (e.g., 400 VAC RMS systems).
I(AV)	25.0 A at T_C = 55°C - Continuous DC output current limit when case temperature is maintained at 55°C via heat-sink interface.
V_F	1.1 V at 12.5 A - Forward voltage drop per conducting diode pair; determines conduction loss (≈27.5 W total at full load).
I_FSM	300 A (8.3 ms) - Non-repetitive surge current rating; supports inrush current handling during cold-start of capacitive-input supplies.
R_JC	2.5 °C/W - Junction-to-case thermal resistance; enables thermal design using measured case temperature instead of ambient.
I²t	373 A²s - Fusing energy threshold; used to coordinate upstream fuse selection for short-circuit protection.
T_J, T_STG	–55°C to +150°C - Extended operating range suitable for enclosed industrial enclosures without forced air cooling.

Pinout & Package

Package: High-conductivity metal case with 0.25" Faston terminals; bolt-down mounting with silicone thermal compound required for rated performance. Dimensions: 28.4–28.7 mm (A) × 10.97–11.23 mm (B) × 15.5–17.6 mm (C); weight ≈29 g.

Pin/Terminal	Circuit Role	Design Meaning
AC1 / AC2	AC Input Terminals	Two independent AC inputs accepting full-wave bridge input; polarity-insensitive for standard line connection.
(+) Output	Positive DC Output Terminal	Common cathode node delivering rectified positive DC; must be connected to load return path via low-inductance route.
(–) Output	Negative DC Output Terminal	Common anode node serving as DC ground reference; electrically isolated from case unless externally bonded.

Key Features

Feature	Design Value
UL 94V-0 metal case	Flame-retardant enclosure meets safety standards for enclosed industrial power modules without additional potting.
Bolt-down thermal interface	Requires mechanical fastening and thermal compound to achieve rated I(AV); eliminates reliance on PCB copper for heat dissipation.
0.25" Faston terminals	Enables field-serviceable wiring with snap-on connectors or direct soldering-reducing assembly time vs. screw terminals.
RoHS-compliant lead-free finish	Complies with EU Directive 2002/95/EC (date code 0514+); supports automated reflow and wave soldering processes.

Applications

Industrial SMPS Front-End

Motor Drive Power Stage

Use Scenario: Rectifying 380 VAC three-phase line (via phase-splitting) or 230 VAC single-phase input in 1–3 kW industrial switch-mode power supplies.

IC Role / Device Role / Timing Role: Full-wave bridge rectifier converting AC line to unregulated DC bus; operates continuously at 25 A average load with 600 V blocking margin.

Use Value: Metal-case thermal path enables >90% derating efficiency at 55°C case temperature-reducing need for oversized heat-sinks.

Use Scenario: DC bus generation for 2–5 HP AC induction motor drives in HVAC and pump control cabinets.

IC Role / Device Role / Timing Role: Primary AC-to-DC conversion stage feeding IGBT inverter; withstands 300 A inrush surges during capacitor pre-charge.

Use Value: 373 A²s I²t rating allows coordination with 32 A slow-blow fuses-ensuring selective protection without nuisance blowing.

Welding Power Supply Input

Uninterruptible Power System (UPS)

Use Scenario: High-duty-cycle rectification in 5–10 kVA arc welding power supplies with intermittent 100% load cycles.

IC Role / Device Role / Timing Role: Line-frequency bridge supplying bulk capacitor charging; thermally coupled directly to aluminum chassis.

Use Value: 2.5 °C/W R_JC permits direct chassis mounting-eliminating thermal interface layers and reducing thermal impedance by ≥40% vs. PCB-mounted alternatives.

Use Scenario: Mains rectification in online double-conversion UPS units requiring high reliability and long service life.

IC Role / Device Role / Timing Role: First-stage AC/DC conversion feeding battery charger and inverter DC bus; operates at 60–80% of rated current continuously.

Use Value: –55°C to +150°C operating range ensures stable performance across wide ambient swings in data center environments.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
GBPC2506	Same 600 V V_RRM, 25 A I(AV), but plastic DIP-4 package with lower R_JC (3.0 °C/W) and no metal case.	Lower thermal mass; unsuitable for bolt-down chassis mounting; requires PCB copper pour or external heat-sink clip.	Select when space-constrained PCB layout prioritizes footprint over thermal coupling efficiency.
KBPC2506	Identical electrical ratings, but ceramic-metal package with higher R_JC (4.0 °C/W) and non-RoHS leaded terminations (pre-2006 date codes).	Limited to legacy repair; incompatible with modern lead-free assembly; lacks UL 94V-0 case rating.	Accept only for field replacement in existing non-RoHS-certified equipment.

Compared with GBPC2506 and KBPC2506, MB256 offers superior thermal transfer via its metal case and bolt-down interface-making it optimal for high-reliability, high-temperature industrial enclosures where thermal management dominates over board space constraints.

Availability

MB256 is available at Aetrix Electronics and suitable for industrial SMPS front-ends, motor drive power stages, and welding power supply inputs requiring stable component supply and long-term lifecycle continuity.

Supply support for MB256 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.

The MB series targets high-power AC/DC conversion applications, emphasizing thermal robustness, mechanical mounting flexibility, and compliance with industrial safety and environmental standards.

FAQ

Is MB256 RoHS-compliant?

Yes, MB256 carries a lead-free finish compliant with EU Directive 2002/95/EC (RoHS), effective for date codes 0514 and later. The exemption for high-temperature solder applies per Annex Notes 5 and 7 of the directive, and the device is qualified for standard reflow and wave soldering processes.

What is the recommended mounting method for MB256?

MB256 must be bolted to a heat-sink using a #10 screw at ≤20 in·lb torque, with silicone thermal compound applied between the metal case and mounting surface. This configuration achieves the rated 25 A output current; PCB-only mounting or adhesive bonding will cause thermal overload and premature failure.

Can MB256 replace MB254 or MB258 in an existing design?

Yes-MB256 is pin-compatible and mechanically identical to other MB25x variants. The only difference is V_RRM: MB254 = 400 V, MB256 = 600 V, MB258 = 800 V. Substitution is safe if the circuit's peak reverse voltage remains ≤600 V; verify AC input transients and snubber design margins before replacement.

Why is MB256 marked "Not Recommended for New Design"?

Diodes Incorporated recommends the GBPC25 series for new designs due to improved thermal performance in smaller plastic packages and broader distribution channel support. MB256 remains fully supported for production and repair, with no announced obsolescence-its metal-case architecture continues to serve niche high-reliability thermal applications.

MB256 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: 4-Square, MB

Packaging:: Bulk

Product Status:: Obsolete

Diode Type:: Single Phase

Technology:: Standard

Voltage - Peak Reverse (Max):: 600 V

Current - Average Rectified (Io):: 25 A

Voltage - Forward (Vf) (Max) @ If:: 1.1 V @ 12.5 A

Current - Reverse Leakage @ Vr:: 10 µA @ 600 V

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: QC Terminal

Supplier Device Package:: MB

MB256 FAQ

1.How can I place an order for MB256 through Aetrix?

Please submit a Request for Quotation (RFQ) for MB256 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 MB256 reliable?

The price and inventory of MB256 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MB256 is usually 5 days.

3.What payment methods are accepted for MB256?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MB256 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MB256?

MB256 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MB256 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 MB256?

For technical support, including MB256 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MB256 requirements.

6.How does Aetrix verify that MB256 is sourced from the original manufacturer or authorized distributors?

All MB256 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 MB256 meets industry standards.

7.What is the process for return or replacement of MB256?

All MB256 units undergo pre-shipment inspection (PSI). If there is an issue with MB256, 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 MB256 part is unused and in its original packaging.

Return procedure for MB256:

1.Submit a request within 90 days.

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

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