KBU4A Bridge Rectifier Equivalent & Substitute Parts

Part Overview

The KBU4A is a single-phase bridge rectifier manufactured by onsemi, rated for 50 V peak reverse voltage and 4 A average rectified current. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. Bridge rectifiers in this voltage and current class are widely used in power supply circuits, battery charging systems, and AC-to-DC conversion applications where single-phase rectification is required.

Key Parameters

Parameter	Value
Diode Type	Single Phase
Technology	Standard
Voltage - Peak Reverse (Max)	50 V
Current - Average Rectified (Io)	4 A
Voltage - Forward (Vf) (Max) @ If	1 V @ 4 A
Current - Reverse Leakage @ Vr	5 µA @ 50 V
Operating Temperature Range	-55°C ~ 150°C (TJ)
Mounting Type	Through Hole
Package / Case	4-SIP, KBU
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the KBU4A is determined by the following critical parameters:

Voltage - Peak Reverse (Max): Must be 50 V or greater
Current - Average Rectified (Io): Must be 4 A or greater
Diode Type: Single Phase
Technology: Standard
Mounting Type: Through Hole
Operating Temperature Range: Must encompass -55°C ~ 150°C or be compatible with application requirements
Package Compatibility: Physical form factor must accommodate 4-SIP configuration

Substitute parts are grouped into two categories:

Direct Equivalents (Same Current Rating): Parts with 4 A average rectified current and identical voltage specifications, suitable for direct replacement without circuit redesign.

Higher Current Capacity Substitutes: Parts rated for 6 A, 8 A, 25 A, or 35 A average rectified current. These provide enhanced current handling capability and are electrically compatible when the application circuit can accommodate higher current capacity.

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
KBU4A	onsemi	50 V	4 A	1 V @ 4 A	5 µA @ 50 V	-55°C ~ 150°C	4-SIP, KBU	Obsolete
GBU4A	Good-Ark Semiconductor	50 V	3 A	1 V @ 2 A	5 µA @ 50 V	-55°C ~ 150°C	4-SIP, GBU	Active
GBU4005-G	Comchip Technology	50 V	4 A	1 V @ 2 A	10 µA @ 50 V	-55°C ~ 150°C	4-SIP, GBU	Active
GBU6005-G	Comchip Technology	50 V	6 A	1 V @ 3 A	10 µA @ 50 V	-55°C ~ 150°C	4-SIP, GBU	Active
GBU8005-G	Comchip Technology	50 V	8 A	1 V @ 4 A	5 µA @ 50 V	-55°C ~ 150°C	4-SIP, GBU	Active
GBU25005-G	Comchip Technology	50 V	25 A	1 V @ 12.5 A	10 µA @ 50 V	-55°C ~ 150°C	4-SIP, GBU	Active
KBL4005-G	Comchip Technology	50 V	4 A	1.1 V @ 4 A	10 µA @ 50 V	-55°C ~ 150°C	4-SIP, KBL	Active
KBU35005-G	Comchip Technology	50 V	35 A	1.1 V @ 17.5 A	10 µA @ 50 V	-55°C ~ 150°C	4-SIP, KBU	Obsolete

Engineering Selection Recommendations

GBU4005-G (Comchip Technology) is the primary substitute for KBU4A. It matches the 4 A current rating and 50 V voltage specification, operates across the identical temperature range, and maintains active product status with RoHS3 compliance. The GBU package form factor is mechanically compatible with through-hole mounting applications.

GBU8005-G (Comchip Technology) is suitable when higher current margin is required. With 8 A average rectified current capacity, it provides 2× the current headroom of the original KBU4A while maintaining all other electrical parameters within compatible ranges. This part is active and RoHS3 compliant.

KBL4005-G (Comchip Technology) provides an alternative with identical 4 A current rating and KBL package configuration. Forward voltage is slightly elevated at 1.1 V versus 1 V, which may affect power dissipation calculations in thermally constrained designs. This part is active and RoHS3 compliant.

GBU6005-G (Comchip Technology) offers 6 A capacity as an intermediate option between the 4 A and 8 A ratings. It is active and RoHS3 compliant.

GBU25005-G and KBU35005-G are suitable only when significantly higher current capacity is required by the application circuit. Both are electrically compatible but represent substantial over-specification for 4 A applications.

GBU4A (Good-Ark Semiconductor) has a lower current rating of 3 A and is not recommended as a substitute for the 4 A KBU4A, as it does not meet the minimum current requirement.

Frequently Asked Questions (FAQ)

Q: Can GBU4005-G directly replace KBU4A without circuit modification?

A: Yes. GBU4005-G matches the critical electrical parameters: 50 V peak reverse voltage, 4 A average rectified current, and -55°C ~ 150°C operating temperature range. The GBU package is mechanically compatible with through-hole mounting. No circuit redesign is required.

Q: What is the difference between GBU and KBU package designations?

A: Both GBU and KBU are 4-SIP through-hole package configurations for single-phase bridge rectifiers. The primary difference is manufacturer convention. GBU is used by Comchip Technology and Good-Ark Semiconductor, while KBU is used by onsemi and other manufacturers. Physical dimensions and pin configurations are compatible for through-hole PCB mounting.

Q: Can I use GBU8005-G instead of KBU4A?

A: Yes. GBU8005-G has higher current capacity (8 A versus 4 A) and is electrically compatible. It will operate safely in circuits designed for 4 A, providing additional current margin. Forward voltage characteristics match the original at 1 V @ 4 A. No circuit modification is necessary.

Q: Why is KBU35005-G listed as a substitute if it has 35 A capacity?

A: KBU35005-G meets all electrical compatibility criteria: 50 V peak reverse voltage, -55°C ~ 150°C operating temperature, and through-hole mounting. While 35 A significantly exceeds the 4 A requirement, it is electrically compatible and may be used if available. However, it represents substantial over-specification and is not recommended for standard 4 A applications.

Q: What is the impact of forward voltage differences between substitutes?

A: Forward voltage variations (1 V to 1.1 V @ rated current) affect power dissipation and heat generation. KBL4005-G has 1.1 V forward voltage versus 1 V for KBU4A and GBU4005-G. In high-current or continuous-duty applications, this 0.1 V difference may increase thermal load. Verify thermal design margins if substituting KBL4005-G in thermally constrained circuits.

Q: Are all substitute parts RoHS3 compliant?

A: All active substitute parts listed (GBU4A, GBU4005-G, GBU6005-G, GBU8005-G, GBU25005-G, KBL4005-G) are RoHS3 compliant. KBU35005-G is also RoHS3 compliant. The original KBU4A is obsolete and REACH unaffected. Verify compliance requirements for your specific application and regulatory jurisdiction.

Q: Can reverse leakage current differences affect circuit performance?

A: The KBU4A specifies 5 µA @ 50 V reverse leakage, while most Comchip substitutes specify 10 µA @ 50 V. This 2× difference is negligible in standard rectifier applications and will not affect circuit functionality. Both values are well within acceptable limits for power supply and charging circuits.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message