Equivalent & Substitute Parts for 3N249

Part Overview

The 3N249 is a single-phase bridge rectifier manufactured by onsemi, rated for 400 V peak reverse voltage and 1.5 A average rectified current in a 4-SIP KBPM through-hole package. This component is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Key Parameters

Parameter	Value
Manufacturer Part Number	3N249
Manufacturer	onsemi
Category	Diodes - Bridge Rectifier
Diode Type	Single Phase
Technology	Standard
Voltage - Peak Reverse (Max)	400 V
Current - Average Rectified (Io)	1.5 A
Voltage - Forward (Vf) (Max) @ If	1 V @ 1 A
Current - Reverse Leakage @ Vr	5 µA @ 400 V
Operating Temperature Range	-55°C to 165°C (TJ)
Mounting Type	Through Hole
Package / Case	4-SIP, KBPM
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the 3N249 is determined by the following critical electrical and mechanical parameters:

Voltage Rating: Peak reverse voltage must be 400 V or higher to maintain circuit protection margins
Current Rating: Average rectified current must be 1.5 A or higher to support load requirements
Diode Type: Single-phase bridge rectifier configuration
Mounting Type: Through-hole package for PCB compatibility
Technology: Standard bridge rectifier technology

Substitute parts are grouped into two categories:

Direct Substitutes (400 V, 1.5 A minimum): Parts meeting or exceeding the exact voltage and current specifications with compatible through-hole packaging.

Functional Alternatives (400 V, higher current ratings): Parts with 400 V voltage rating and current ratings of 2 A or higher, which provide enhanced current capacity while maintaining voltage compatibility.

Parameter Comparison

Parameter	3N249 (onsemi)	KBP04G (Diodes Inc.)	KBP204G (SMC)	VS-2KBP04 (Vishay)
Voltage - Peak Reverse (Max)	400 V	400 V	400 V	400 V
Current - Average Rectified (Io)	1.5 A	1.5 A	2 A	2 A
Voltage - Forward (Vf) (Max) @ If	1 V @ 1 A	1.1 V @ 1.5 A	1.1 V @ 2 A	1 V @ 1 A
Current - Reverse Leakage @ Vr	5 µA @ 400 V	5 µA @ 400 V	5 µA @ 400 V	10 µA @ 400 V
Operating Temperature Range	-55°C to 165°C	-65°C to 150°C	-55°C to 150°C	-40°C to 150°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	4-SIP, KBPM	4-SIP, KBP	4-ESIP	4-SIP, D-44
Product Status	Obsolete	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitute: KBP04G (Diodes Incorporated)

The KBP04G is the closest functional equivalent to the 3N249. It matches the 400 V voltage rating and 1.5 A current specification exactly. The part is active in production status with ROHS3 compliance. The 4-SIP KBP package is mechanically compatible with standard through-hole PCB layouts. Operating temperature range extends to -65°C, providing superior low-temperature performance compared to the 3N249.

Secondary Substitute: VS-2KBP04 (Vishay General Semiconductor)

The VS-2KBP04 provides 400 V voltage rating with 2 A current capacity, offering increased current margin. This part is active in production with ROHS3 compliance. The 4-SIP D-44 package is through-hole compatible. The higher current rating accommodates designs with future load expansion requirements.

Alternative for Higher Current Applications: KBP204G (SMC Diode Solutions)

The KBP204G maintains the 400 V voltage specification while providing 2 A current capacity. This part is active in production with ROHS3 compliance. The 4-ESIP package is through-hole compatible. REACH compliance status is affected; verify regulatory requirements for your application.

Lower Voltage Alternatives (Not Recommended for Direct Substitution)

Parts such as VS-2KBP005 (50 V), VS-2KBP02 (200 V), VS-2KBP06 (600 V), VS-2KBP08 (800 V), and VS-2KBP10 (1 kV) have voltage ratings that deviate from the 400 V specification. These parts are suitable only for applications with different voltage requirements and should not be used as direct replacements for the 3N249 in 400 V circuits.

Frequently Asked Questions (FAQ)

Q: Can I use KBP04G as a direct replacement for 3N249?

A: Yes. The KBP04G matches the 3N249 in voltage rating (400 V) and current rating (1.5 A). Both are single-phase bridge rectifiers in through-hole packages. The KBP04G is active in production, whereas the 3N249 is obsolete.

Q: What is the difference between KBP04G and KBP204G?

A: Both parts are rated for 400 V peak reverse voltage. The KBP04G is rated for 1.5 A average rectified current, while the KBP204G is rated for 2 A. The KBP204G provides higher current capacity for applications requiring additional margin.

Q: Are the package dimensions identical between 3N249 (KBPM) and KBP04G (KBP)?

A: Both use 4-SIP through-hole packages. While the package designations differ (KBPM vs. KBP), both are compatible with standard through-hole PCB layouts. Verify footprint compatibility with your specific PCB design before production.

Q: Why are VS-2KBP series parts listed if they have different voltage ratings?

A: The VS-2KBP series includes parts with voltage ratings ranging from 50 V to 1 kV. Only VS-2KBP04 (400 V, 2 A) is suitable as a substitute for the 3N249. Other voltage ratings in this series are listed for reference but are not appropriate for 400 V applications.

Q: What is the impact of forward voltage differences between 3N249 and substitute parts?

A: The 3N249 specifies 1 V forward voltage at 1 A. Substitute parts such as KBP04G specify 1.1 V at 1.5 A. This 0.1 V difference results in slightly higher power dissipation. For most applications, this difference is negligible. Verify thermal design margins if operating near maximum current ratings.

Q: Are all recommended substitutes RoHS compliant?

A: Yes. KBP04G, KBP204G, and VS-2KBP04 are all ROHS3 compliant. The 3N249 does not specify RoHS status. Verify compliance requirements for your application and supply chain.

Q: Can I use a higher voltage-rated part such as VS-2KBP06 (600 V) in place of the 3N249 (400 V)?

A: Higher voltage ratings do not provide functional substitution for lower voltage applications. The VS-2KBP06 is designed for 600 V circuits and is not appropriate for 400 V designs. Use parts rated for 400 V or higher only when the circuit design specifically requires that voltage rating.

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