MB258W-BP Bridge Rectifier Single Phase 800V 25A Equivalent & Substitute Parts

Part Overview

The MB258W-BP is a single-phase bridge rectifier manufactured by Micro Commercial Co, rated for 800V peak reverse voltage and 25A average rectified current in a through-hole 4-Square MB-35W package. This component is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing system maintenance and new design implementations. The MB258W-BP serves as a standard bridge rectification solution for industrial power supply applications requiring robust voltage and current handling capabilities.

Key Parameters

Parameter	Value
Diode Type	Single Phase
Technology	Standard
Voltage - Peak Reverse (Max)	800 V
Current - Average Rectified (Io)	25 A
Voltage - Forward (Vf) (Max) @ If	1.2 V @ 12.5 A
Current - Reverse Leakage @ Vr	10 µA @ 600 V
Operating Temperature Range	-55°C ~ 125°C (TJ)
Mounting Type	Through Hole
Package / Case	4-Square, MB-35W
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the MB258W-BP is determined by strict equivalence across the following critical parameters:

Voltage Rating: Peak reverse voltage must equal or exceed 800V
Current Rating: Average rectified current must equal or exceed 25A
Diode Configuration: Single-phase bridge rectifier topology
Mounting Technology: Through-hole package compatibility
Package Form Factor: 4-Square package footprint compatibility
Regulatory Compliance: ROHS3 compliance and REACH unaffected status

The KBPC2508W-G from Comchip Technology meets all substitution criteria and is classified as an active product, providing long-term availability advantages over the obsolete MB258W-BP.

Parameter Comparison

Parameter	MB258W-BP (Main Part)	KBPC2508W-G (Substitute)	Compatibility
Manufacturer	Micro Commercial Co	Comchip Technology	Different manufacturer
Diode Type	Single Phase	Single Phase	Equivalent
Technology	Standard	Standard	Equivalent
Voltage - Peak Reverse (Max)	800 V	800 V	Equivalent
Current - Average Rectified (Io)	25 A	25 A	Equivalent
Voltage - Forward (Vf) (Max) @ If	1.2 V @ 12.5 A	1.1 V @ 12.5 A	KBPC2508W-G superior
Current - Reverse Leakage @ Vr	10 µA @ 600 V	10 µA @ 800 V	KBPC2508W-G superior
Operating Temperature Range	-55°C ~ 125°C (TJ)	-55°C ~ 150°C (TJ)	KBPC2508W-G superior
Mounting Type	Through Hole	Through Hole	Equivalent
Package / Case	4-Square, MB-35W	4-Square, KBPC-W	Equivalent form factor
Product Status	Obsolete	Active	KBPC2508W-G preferred
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
REACH Status	REACH Unaffected	REACH Unaffected	Equivalent

Engineering Selection Recommendations

The KBPC2508W-G is the qualified substitute for the obsolete MB258W-BP. Selection rationale is based on the following factors:

Electrical Equivalence: Both components share identical peak reverse voltage (800V) and average rectified current (25A) ratings, ensuring functional compatibility in existing circuit designs.

Superior Performance Characteristics: The KBPC2508W-G demonstrates improved forward voltage drop (1.1V versus 1.2V at 12.5A) and extended reverse leakage measurement capability (10µA @ 800V versus 10µA @ 600V), indicating enhanced device performance margins.

Extended Operating Temperature Range: The KBPC2508W-G supports -55°C to 150°C operation compared to -55°C to 125°C for the MB258W-BP, providing additional thermal headroom for demanding applications.

Active Product Status: The KBPC2508W-G is classified as active, ensuring long-term availability, supply chain stability, and continued manufacturer support, eliminating obsolescence risk associated with the MB258W-BP.

Regulatory Compliance: Both components maintain ROHS3 compliance and REACH unaffected status, satisfying environmental and regulatory requirements without modification.

Package Compatibility: Both components utilize 4-Square through-hole packages with equivalent mechanical footprints, enabling direct board-level substitution without PCB redesign.

Frequently Asked Questions (FAQ)

Q: Can the KBPC2508W-G be used as a direct replacement for the MB258W-BP without circuit modification?

A: Yes. The KBPC2508W-G meets all electrical and mechanical substitution criteria. Identical voltage and current ratings, equivalent package form factor, and compatible mounting technology enable direct substitution. The improved forward voltage and extended temperature range present no compatibility issues.

Q: What are the key differences between these two bridge rectifiers?

A: The primary differences are manufacturer origin, product status, and performance characteristics. The KBPC2508W-G offers lower forward voltage drop (1.1V versus 1.2V), extended reverse leakage measurement capability, higher maximum operating temperature (150°C versus 125°C), and active product status versus obsolete classification.

Q: Are there any thermal or electrical derating considerations when substituting the KBPC2508W-G for the MB258W-BP?

A: No derating is required. The KBPC2508W-G maintains equivalent voltage and current ratings with superior thermal characteristics. The lower forward voltage drop may reduce heat dissipation requirements in the application.

Q: Do both components require identical PCB footprints?

A: Yes. Both components use 4-Square through-hole packages with equivalent mechanical dimensions, allowing direct PCB substitution without layout modification.

Q: What is the significance of the MB258W-BP being classified as obsolete?

A: Obsolete classification indicates the manufacturer has discontinued production and support. The KBPC2508W-G, classified as active, ensures continued availability, supply chain reliability, and manufacturer technical support for future applications and maintenance requirements.

Q: Are there compliance or certification differences between these components?

A: No. Both components maintain ROHS3 compliance and REACH unaffected status, satisfying identical regulatory and environmental requirements.

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