Equivalent & Substitute Parts for 3N257

Part Overview

The 3N257 is a single-phase bridge rectifier manufactured by onsemi, rated for 600 V peak reverse voltage and 2 A average rectified current. It features a 4-SIP KBPM package for through-hole mounting and operates across a temperature range of -55°C to 150°C. The part is currently obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Diode Type	Single Phase
Voltage - Peak Reverse (Max)	600 V
Current - Average Rectified (Io)	2 A
Voltage - Forward (Vf) (Max) @ If	1.1 V @ 3.14 A
Current - Reverse Leakage @ Vr	5 µA @ 600 V
Operating Temperature Range	-55°C to 150°C (TJ)
Mounting Type	Through Hole
Package / Case	4-SIP, KBPM
Technology	Standard

Substitute Part Grouping Explanation

Substitution eligibility for the 3N257 is determined by the following critical parameters:

Voltage - Peak Reverse (Max): Must be ≥ 600 V to maintain voltage margin
Current - Average Rectified (Io): Must be ≥ 2 A to support load requirements
Diode Type: Must be Single Phase
Technology: Must be Standard
Mounting Type: Must be Through Hole
Package / Case: Must be compatible 4-SIP form factor (KBPM or KBP variants acceptable)

Substitute parts are grouped into two categories:

Category A - Direct Voltage/Current Match (600 V, 2 A): Parts meeting or exceeding both 600 V and 2 A specifications with compatible packaging.

Category B - Voltage Match with Lower Current (600 V, <2 A): Parts meeting 600 V specification but with reduced current ratings. These are suitable only for applications with lower current demands than the original 2 A specification.

Parameter Comparison

Part Number	Manufacturer	Voltage - Peak Reverse (Max)	Current - Average Rectified (Io)	Voltage - Forward (Vf) (Max) @ If	Current - Reverse Leakage @ Vr	Operating Temperature	Package / Case	Product Status
3N257	onsemi	600 V	2 A	1.1 V @ 3.14 A	5 µA @ 600 V	-55°C to 150°C	4-SIP, KBPM	Obsolete
KBP06G	Diodes Incorporated	600 V	1.5 A	1.1 V @ 1.5 A	5 µA @ 600 V	-65°C to 150°C	4-SIP, KBP	Active
KBP206G	Diotec Semiconductor	600 V	1.2 A	1.1 V @ 2 A	5 µA @ 600 V	-50°C to 150°C	4-SIP, KBP	Active
VS-2KBP06	Vishay General Semiconductor - Diodes Division	600 V	2 A	1 V @ 1 A	10 µA @ 600 V	-40°C to 150°C	4-SIP, D-44	Active

Engineering Selection Recommendations

Primary Substitute: VS-2KBP06

The VS-2KBP06 from Vishay General Semiconductor - Diodes Division is the most direct equivalent to the 3N257. It matches the critical specifications of 600 V peak reverse voltage and 2 A average rectified current. The part is currently active in production with RoHS3 compliance and REACH unaffected status. The D-44 package is mechanically compatible with the KBPM form factor for through-hole mounting. Operating temperature range of -40°C to 150°C covers the upper portion of the original specification.

Secondary Substitutes: KBP06G and KBP206G

KBP06G (Diodes Incorporated) and KBP206G (Diotec Semiconductor) are suitable for applications where current demand does not exceed 1.5 A and 1.2 A respectively. Both maintain the 600 V voltage specification and are active products. KBP06G offers an extended lower temperature limit of -65°C. These parts are appropriate for reduced-load variants of the original application.

Compliance Considerations

VS-2KBP06 carries RoHS3 compliance certification and REACH unaffected status, meeting modern regulatory requirements. KBP06G also maintains RoHS3 compliance. KBP206G compliance status is not fully defined in available documentation.

Frequently Asked Questions (FAQ)

Q: Can KBP06G replace the 3N257 in all applications?

A: KBP06G is suitable only for applications requiring ≤1.5 A average rectified current. The 3N257 is rated for 2 A, so KBP06G cannot be used as a direct replacement in designs demanding the full 2 A specification. Verify your application's actual current requirements before substitution.

Q: What is the difference between the KBPM and KBP package designations?

A: Both KBPM and KBP are 4-SIP through-hole packages formats for bridge rectifiers. They are mechanically compatible for PCB mounting, though pin spacing and footprint dimensions should be verified against your specific PCB design.

Q: Is the D-44 package compatible with KBPM footprints?

A: The D-44 package used by Vishay parts is a 4-SIP form factor compatible with KBPM mounting requirements. Verify PCB footprint dimensions and pin pitch specifications to ensure mechanical fit in your application.

Q: Why does VS-2KBP06 have a higher reverse leakage current (10 µA vs 5 µA)?

A: Reverse leakage current variation is within normal manufacturing tolerances for bridge rectifier technology. Both values remain well within acceptable limits for standard rectification applications. Verify your circuit design can accommodate this parameter if leakage current is critical to your application.

Q: Can I use VS-2KBP10 (1 kV rated) instead of the 3N257?

A: VS-2KBP10 exceeds the voltage specification of the 3N257 and maintains the 2 A current rating. Higher voltage-rated components can be used in lower-voltage applications without functional degradation. However, verify that your PCB layout and thermal management accommodate the substitute part's physical dimensions and thermal characteristics.

Q: What compliance certifications should I verify for production use?

A: For new production designs, confirm RoHS compliance status and REACH compliance of your selected substitute. VS-2KBP06 carries RoHS3 compliance and REACH unaffected status, meeting current regulatory requirements for most markets.

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