KBU8G Bridge Rectifier Equivalent & Substitute Parts

Part Overview

The KBU8G is a single-phase bridge rectifier manufactured by onsemi, rated for 400 V peak reverse voltage and 8 A average rectified current. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. Bridge rectifiers in the KBU and GBU series serve identical functional roles in AC-to-DC conversion applications, with substitution determined by electrical ratings and mechanical compatibility.

Key Parameters

Parameter	Value
Voltage - Peak Reverse (Max)	400 V
Current - Average Rectified (Io)	8 A
Voltage - Forward (Vf) (Max) @ If	1 V @ 8 A
Current - Reverse Leakage @ Vr	10 µA @ 400 V
Operating Temperature Range	-55°C ~ 150°C (TJ)
Mounting Type	Through Hole
Package / Case	4-SIP, KBU
Diode Type	Single Phase
Technology	Standard

Substitute Part Grouping Explanation

Substitution of the KBU8G is based on the following criteria:

Primary Substitution Criteria:

Voltage - Peak Reverse (Max): 400 V (exact match required)
Diode Type: Single Phase (exact match required)
Technology: Standard (exact match required)
Mounting Type: Through Hole (exact match required)
Operating Temperature Range: -55°C ~ 150°C (exact match required)

Secondary Substitution Criteria:

Current - Average Rectified (Io): 8 A or higher
Voltage - Forward (Vf) (Max) @ If: 1 V or lower
Current - Reverse Leakage @ Vr: 10 µA or lower @ 400 V
Package / Case: 4-SIP configuration (KBU or GBU series)

Substitute parts meeting all primary criteria and equal or superior secondary criteria are electrically and mechanically compatible with the KBU8G. The GBU series from Comchip Technology and Vishay General Semiconductor - Diodes Division share identical electrical specifications and package footprints with the KBU series, enabling direct substitution.

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
KBU8G	onsemi	400 V	8 A	1 V @ 8 A	10 µA @ 400 V	-55°C ~ 150°C	4-SIP, KBU	Obsolete
GBU804-G	Comchip Technology	400 V	8 A	1 V @ 4 A	10 µA @ 400 V	-55°C ~ 150°C	4-SIP, GBU	Active
GBU604-G	Comchip Technology	400 V	6 A	1 V @ 3 A	10 µA @ 400 V	-55°C ~ 150°C	4-SIP, GBU	Active
GBU404-G	Comchip Technology	400 V	4 A	1 V @ 2 A	10 µA @ 400 V	-55°C ~ 150°C	4-SIP, GBU	Active
GBU2504-G	Comchip Technology	400 V	25 A	1 V @ 12.5 A	10 µA @ 400 V	-55°C ~ 150°C	4-SIP, GBU	Active
GBU8G-E3/45	Vishay General Semiconductor - Diodes Division	400 V	3.9 A	1 V @ 8 A	5 µA @ 400 V	-55°C ~ 150°C	4-SIP, GBU	Active

Engineering Selection Recommendations

Direct Equivalent (Recommended Primary Choice): GBU804-G from Comchip Technology is the primary equivalent for KBU8G replacement. Both parts share identical 400 V / 8 A ratings, matching forward voltage characteristics, and equivalent reverse leakage specifications. GBU804-G is in active production status with ROHS3 compliance, ensuring long-term availability and regulatory alignment.

Alternative Equivalents (Current Rating Dependent):

GBU8G-E3/45 from Vishay General Semiconductor - Diodes Division meets the 8 A specification with superior reverse leakage performance (5 µA vs. 10 µA). This part is in active production with ROHS3 compliance.
GBU604-G and GBU404-G are suitable only for applications requiring 6 A or 4 A maximum current respectively. These parts are in active production with ROHS3 compliance.
GBU2504-G is suitable for applications requiring higher current capacity (25 A). This part is in active production with ROHS3 compliance.

All substitute parts maintain the 4-SIP through-hole package configuration, -55°C to 150°C operating temperature range, and 400 V peak reverse voltage specification of the original KBU8G.

Frequently Asked Questions (FAQ)

Q: Can GBU804-G directly replace KBU8G in existing designs? A: Yes. GBU804-G and KBU8G share identical electrical specifications (400 V, 8 A, 1 V forward voltage @ 8 A, 10 µA reverse leakage @ 400 V) and both use the 4-SIP through-hole package. No circuit modifications are required.

Q: What is the difference between KBU and GBU package designations? A: KBU and GBU are series designations from different manufacturers (onsemi and Comchip Technology / Vishay respectively). Both use identical 4-SIP through-hole package footprints and are mechanically and electrically interchangeable when electrical ratings match.

Q: Can I use GBU2504-G as a substitute for KBU8G? A: Yes, GBU2504-G is electrically compatible. It provides higher current capacity (25 A vs. 8 A), which is acceptable for applications designed for 8 A operation. The 400 V voltage rating, operating temperature range, and package configuration are identical.

Q: Can I use GBU404-G or GBU604-G as substitutes for KBU8G? A: GBU404-G (4 A) and GBU604-G (6 A) have lower current ratings than the KBU8G (8 A). These parts are suitable only if your application requires 4 A or 6 A maximum current respectively. Using an undersized current rating may result in component failure.

Q: What is the significance of the "Obsolete" status for KBU8G? A: Obsolete status indicates that onsemi has discontinued production of the KBU8G. Active production alternatives from Comchip Technology and Vishay General Semiconductor - Diodes Division ensure continued availability and supply chain stability.

Q: Are all substitute parts ROHS3 compliant? A: GBU804-G, GBU604-G, GBU404-G, GBU2504-G, and GBU8G-E3/45 are all ROHS3 compliant. The original KBU8G does not specify ROHS status.

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