KBU6G Bridge Rectifier Equivalent & Substitute Parts

Part Overview

The KBU6G is a single-phase bridge rectifier diode manufactured by onsemi, rated for 400 V peak reverse voltage and 6 A average rectified current. This component is designed for through-hole mounting in 4-SIP KBU package configuration. The KBU6G is currently classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Diode Type	Single Phase Bridge Rectifier
Voltage - Peak Reverse (Max)	400 V
Current - Average Rectified (Io)	6 A
Voltage - Forward (Vf) (Max) @ If	1 V @ 6 A
Current - Reverse Leakage @ Vr	5 µA @ 400 V
Operating Temperature Range	-55°C to 150°C (TJ)
Mounting Type	Through Hole
Package / Case	4-SIP, KBU
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the KBU6G is determined by the following critical parameters:

Voltage Rating: Peak reverse voltage must be 400 V or greater
Current Rating: Average rectified current must meet or exceed 6 A
Diode Type: Single-phase bridge rectifier configuration
Mounting Type: Through-hole mounting required
Package Compatibility: Physical form factor must accommodate 4-SIP or equivalent through-hole footprint
Temperature Range: Operating temperature range must encompass -55°C to 150°C

Substitute parts are grouped into two categories:

Direct Manufacturer Equivalent: GBU6G (Fairchild Semiconductor) matches the 6 A current rating and 400 V voltage specification with identical forward voltage characteristics at rated current.

Similar Current Rating Alternatives: GBU404-G, GBU604-G, and GBU804-G (Comchip Technology) provide 4 A, 6 A, and 8 A ratings respectively, all rated for 400 V peak reverse voltage with through-hole mounting in compatible GBU package configurations.

Higher Current Capacity Alternative: GBU2504-G (Comchip Technology) provides 25 A capacity at 400 V for applications requiring increased current handling.

Parameter Comparison

Parameter	KBU6G (onsemi)	GBU6G (Fairchild)	GBU404-G (Comchip)	GBU604-G (Comchip)	GBU804-G (Comchip)	GBU2504-G (Comchip)
Voltage - Peak Reverse (Max)	400 V	400 V	400 V	400 V	400 V	400 V
Current - Average Rectified (Io)	6 A	4.2 A	4 A	6 A	8 A	25 A
Voltage - Forward (Vf) (Max) @ If	1 V @ 6 A	1 V @ 6 A	1 V @ 2 A	1 V @ 3 A	1 V @ 4 A	1 V @ 12.5 A
Current - Reverse Leakage @ Vr	5 µA @ 400 V	5 µA @ 400 V	10 µA @ 400 V	10 µA @ 400 V	10 µA @ 400 V	10 µA @ 400 V
Operating Temperature Range	-55°C to 150°C	-50°C to 150°C	-55°C to 150°C	-55°C to 150°C	-55°C to 150°C	-55°C to 150°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	4-SIP, KBU	4-ESIP, GBU	4-SIP, GBU	4-SIP, GBU	4-SIP, GBU	4-SIP, GBU
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	Not specified	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitute: GBU6G (Fairchild Semiconductor) is the direct equivalent for KBU6G replacement. It maintains identical voltage and current ratings with matching forward voltage characteristics. The operating temperature minimum of -50°C versus -55°C for the original part represents a minor deviation suitable for most applications. GBU6G is currently in active production status.

Alternative Selections Based on Application Requirements:

GBU604-G (Comchip Technology): Provides exact 6 A current rating with 400 V voltage specification. ROHS3 compliant. Suitable for direct substitution where RoHS compliance is required.
GBU804-G (Comchip Technology): Rated for 8 A at 400 V, providing 33% current margin above the original 6 A specification. ROHS3 compliant. Appropriate for applications requiring enhanced current capacity or thermal margin.
GBU404-G (Comchip Technology): Rated for 4 A at 400 V. Suitable only for applications where the load current does not exceed 4 A. ROHS3 compliant.
GBU2504-G (Comchip Technology): Rated for 25 A at 400 V. Appropriate for applications requiring significantly higher current capacity. ROHS3 compliant.

All substitute parts maintain through-hole mounting configuration and 400 V peak reverse voltage rating. Package footprints (GBU versus KBU) are mechanically compatible for through-hole PCB mounting, though verification of specific PCB layout is recommended.

Frequently Asked Questions (FAQ)

Q: Can GBU6G directly replace KBU6G without PCB modifications?

A: GBU6G and KBU6G both use 4-pin through-hole configurations with compatible electrical ratings. The GBU and KBU package designations indicate different manufacturer conventions but maintain compatible pin spacing and mounting footprints for standard through-hole PCB layouts. Physical verification of the specific PCB design is recommended.

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

A: GBU and KBU are manufacturer-specific package designations for single-phase bridge rectifiers in 4-pin through-hole configuration. Both packages are mechanically and electrically compatible for standard through-hole mounting applications. The designation reflects the original manufacturer's naming convention rather than functional differences.

Q: Is GBU6G suitable if the application operates at temperatures below -50°C?

A: GBU6G specifies an operating temperature minimum of -50°C, compared to -55°C for the original KBU6G. Applications requiring operation at -55°C should use GBU604-G, GBU804-G, GBU404-G, or GBU2504-G (all rated to -55°C), or confirm that -50°C minimum is acceptable for the specific application.

Q: What is the significance of the current rating difference between KBU6G (6 A) and GBU6G (4.2 A)?

A: GBU6G is rated for 4.2 A average rectified current, which is lower than the KBU6G 6 A rating. For applications requiring the full 6 A capacity, GBU604-G (6 A) or GBU804-G (8 A) are appropriate selections. For applications with load current below 4.2 A, GBU6G is suitable.

Q: Are all substitute parts RoHS compliant?

A: GBU404-G, GBU604-G, GBU804-G, and GBU2504-G are all ROHS3 compliant. The original KBU6G RoHS status is not specified in the available documentation. Confirm RoHS compliance requirements for your specific application.

Q: What is the difference in reverse leakage current between KBU6G and the substitute parts?

A: KBU6G specifies 5 µA reverse leakage at 400 V, while Comchip alternatives (GBU404-G, GBU604-G, GBU804-G, GBU2504-G) specify 10 µA at 400 V. GBU6G matches the original 5 µA specification. For applications sensitive to reverse leakage, GBU6G or KBU6G are preferred.

Q: Can I use a higher current-rated part like GBU804-G or GBU2504-G as a substitute?

A: Yes. Higher current-rated parts (GBU804-G at 8 A or GBU2504-G at 25 A) are electrically compatible substitutes for the 6 A KBU6G. These parts provide additional current capacity and thermal margin. Physical PCB layout verification is recommended to confirm mounting compatibility.

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