3N256 Bridge Rectifier Single Phase 400V 2A - Equivalent & Substitute Parts

Part Overview

The 3N256 is a single-phase bridge rectifier manufactured by onsemi, rated for 400 V peak reverse voltage and 2 A average rectified current. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The 3N256 features a through-hole KBPM package and operates across a temperature range of -55°C to 150°C. Substitute parts must maintain electrical compatibility while meeting current product availability and compliance requirements.

Key Parameters

Parameter	Value
Diode Type	Single Phase
Technology	Standard
Voltage - Peak Reverse (Max)	400 V
Current - Average Rectified (Io)	2 A
Voltage - Forward (Vf) (Max) @ If	1.1 V @ 3.14 A
Current - Reverse Leakage @ Vr	5 µA @ 400 V
Operating Temperature Range	-55°C ~ 150°C (TJ)
Mounting Type	Through Hole
Package / Case	4-SIP, KBPM
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the 3N256 is determined by the following critical parameters:

Voltage - Peak Reverse (Max): Must be ≥ 400 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
Operating Temperature Range: Must encompass or exceed -55°C ~ 150°C

Substitute parts are grouped into two categories:

Category A - Direct Electrical Equivalents (400 V, 2 A): Parts meeting exact voltage and current specifications with active product status and modern compliance certifications.

Category B - Higher Voltage Rated Alternatives (≥ 400 V, 2 A): Parts with voltage ratings exceeding 400 V but maintaining 2 A current rating. These provide enhanced voltage margin and are suitable for applications where higher voltage headroom is acceptable.

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	RoHS Status
3N256	onsemi	400 V	2 A	1.1 V @ 3.14 A	5 µA @ 400 V	-55°C ~ 150°C	4-SIP, KBPM	Obsolete	Not Specified
KBP04G	Diodes Incorporated	400 V	1.5 A	1.1 V @ 1.5 A	5 µA @ 400 V	-65°C ~ 150°C	4-SIP, KBP	Active	ROHS3 Compliant
KBP204G	SMC Diode Solutions	400 V	2 A	1.1 V @ 2 A	5 µA @ 400 V	-55°C ~ 150°C	4-ESIP	Active	ROHS3 Compliant
VS-2KBP005	Vishay General Semiconductor - Diodes Division	50 V	2 A	1 V @ 1 A	10 µA @ 50 V	-40°C ~ 150°C	4-SIP, D-44	Active	ROHS3 Compliant
VS-2KBP02	Vishay General Semiconductor - Diodes Division	200 V	2 A	1 V @ 1 A	10 µA @ 200 V	-40°C ~ 150°C	4-SIP, D-44	Active	ROHS3 Compliant
VS-2KBP04	Vishay General Semiconductor - Diodes Division	400 V	2 A	1 V @ 1 A	10 µA @ 400 V	-40°C ~ 150°C	4-SIP, D-44	Active	ROHS3 Compliant
VS-2KBP06	Vishay General Semiconductor - Diodes Division	600 V	2 A	1 V @ 1 A	10 µA @ 600 V	-40°C ~ 150°C	4-SIP, D-44	Active	ROHS3 Compliant
VS-2KBP08	Vishay General Semiconductor - Diodes Division	800 V	2 A	1 V @ 1 A	10 µA @ 800 V	-40°C ~ 150°C	4-SIP, D-44	Active	ROHS3 Compliant
VS-2KBP10	Vishay General Semiconductor - Diodes Division	1 kV	2 A	1 V @ 1 A	10 µA @ 1000 V	-40°C ~ 150°C	4-SIP, D-44	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitute - KBP204G (SMC Diode Solutions): The KBP204G provides exact electrical equivalence to the 3N256, matching 400 V peak reverse voltage and 2 A average rectified current. This part is active, ROHS3 compliant, and maintains the same operating temperature range. The 4-ESIP package is mechanically compatible with through-hole mounting applications. This is the preferred substitute for direct replacement.

Secondary Substitute - VS-2KBP04 (Vishay General Semiconductor - Diodes Division): The VS-2KBP04 matches the critical electrical parameters of 400 V and 2 A with active product status and ROHS3 compliance. The D-44 package provides through-hole mounting compatibility. The operating temperature range of -40°C to 150°C covers the upper portion of the 3N256 specification. This part is suitable where the lower temperature limit of -40°C is acceptable.

Higher Voltage Alternatives - VS-2KBP06, VS-2KBP08, VS-2KBP10: These Vishay parts maintain 2 A current rating with voltage ratings of 600 V, 800 V, and 1 kV respectively. All are active, ROHS3 compliant, and feature through-hole D-44 packages. These are appropriate for applications requiring enhanced voltage margin beyond the 400 V specification.

Not Recommended - KBP04G: Although active and ROHS3 compliant, the KBP04G is rated for only 1.5 A average rectified current, which falls below the 2 A requirement of the 3N256. This part is unsuitable for direct substitution.

Not Recommended - VS-2KBP005, VS-2KBP02: These parts have voltage ratings of 50 V and 200 V respectively, both below the 400 V requirement. These are unsuitable for direct substitution.

Frequently Asked Questions (FAQ)

Q: Can KBP04G replace the 3N256? A: No. The KBP04G is rated for 1.5 A average rectified current, which is below the 3N256 specification of 2 A. Using an undersized current rating may result in thermal stress and reduced component reliability.

Q: What is the difference between the KBP204G and VS-2KBP04? A: Both parts meet the 400 V and 2 A electrical requirements. The KBP204G uses a 4-ESIP package and maintains the full -55°C to 150°C temperature range. The VS-2KBP04 uses a D-44 package and operates from -40°C to 150°C. Selection depends on the application's minimum operating temperature requirement and PCB layout constraints.

Q: Can I use VS-2KBP06 or higher voltage parts instead of the 3N256? A: Yes. Parts with voltage ratings exceeding 400 V (such as VS-2KBP06 at 600 V, VS-2KBP08 at 800 V, or VS-2KBP10 at 1 kV) are electrically compatible substitutes. The higher voltage rating provides additional safety margin and does not degrade performance in 400 V applications. Package and temperature range compatibility must be verified for the specific application.

Q: Are all substitute parts RoHS compliant? A: The 3N256 does not specify RoHS status. All recommended substitute parts (KBP204G, VS-2KBP04, VS-2KBP06, VS-2KBP08, VS-2KBP10) are ROHS3 compliant, meeting current environmental and regulatory requirements.

Q: What is the difference between KBPM and D-44 packages? A: Both are 4-SIP through-hole packages. The KBPM is the original onsemi package designation, while D-44 is the Vishay package designation. Both provide equivalent through-hole mounting compatibility, though PCB footprint dimensions may differ slightly. Verify footprint compatibility with your PCB design before substitution.

Q: Why do some substitute parts have lower reverse leakage current specifications? A: The 3N256 specifies 5 µA reverse leakage at 400 V, while Vishay parts specify 10 µA at their respective voltages. This difference reflects manufacturing process variations between manufacturers. Both values are within acceptable limits for standard bridge rectifier applications and do not affect functional compatibility.

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