Taiwan Semiconductor Corporation KBU1004G T0G

Overview

KBU1004G from Taiwan Semiconductor is a 10A, 400V repetitive peak reverse voltage (VRRM) standard bridge rectifier in KBU package, featuring glass-passivated junctions, 200A surge capability, and UL recognition (E-326243). It serves as the AC-to-DC front-end conversion stage in compact off-line power supplies, delivering reliable full-wave rectification with low forward voltage (1.1V at 10A, 25°C) and minimal leakage (≤5µA at 25°C).

For engineers reviewing the KBU1004G datasheet, KBU1004G pinout, KBU1004G application, or KBU1004G equivalent, key selection criteria include VRRM rating for input voltage margin, IFSM for inrush resilience, thermal resistance (RθJC = 2.2°C/W), RoHS compliance, and UL recognition for safety-critical designs.

Technical Context

The KBU1004G integrates four silicon diodes in a single-phase full-wave bridge configuration, enabling direct AC line rectification without external interconnection. Its glass-passivated junction ensures stable reverse characteristics across temperature and long-term reliability under repeated surge stress.

Thermally, it uses a molded KBU case with UL 94V-0 compound and matte tin-plated leads compliant with J-STD-002 solderability and JESD201 Class 1A whisker resistance. Junction-to-case thermal resistance is 2.2°C/W, supporting conduction-cooled mounting on PCBs or heatsinks.

Key Specifications

Pinout & Package

Package: KBU - Molded plastic case with 4 axial leads (AC1, AC2, +, –), UL 94V-0 rated, 7.2g weight, designed for through-hole PCB mounting and mechanical robustness.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bridge rectifier applications.

Compared with GBU1004 and W04M, the KBU1004G uniquely balances 10A current capacity, 400V rating, UL recognition, and KBU package thermal performance-making it optimal for mid-power industrial and commercial AC-DC conversion where reliability and regulatory compliance are mandatory.

Availability

KBU1004G is available at Aetrix Electronics and suitable for switching mode power supplies, AC-DC adapters, and LED driver power stages requiring stable component supply, consistent parametric performance, and long-term manufacturability.

Supply support for KBU1004G includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global power, automotive, and industrial markets since 1979.

The KBU1004G belongs to TSC's standard bridge rectifier product line, engineered specifically for cost-sensitive yet reliability-critical AC-DC front-end applications in commercial and industrial power conversion equipment.

FAQ

What is the maximum repetitive peak reverse voltage (VRRM) of the KBU1004G?

The KBU1004G has a VRRM rating of 400 V, verified per Taiwan Semiconductor's official datasheet (Version J2103). This value defines the highest instantaneous reverse voltage the device can block repeatedly without breakdown. It is selected to provide adequate margin above the peak line voltage in 230VAC systems (≈325V), ensuring robust operation during transients and brownouts. The KBU1004G is part of the KBU1001G–KBU1007G family, where the numeric suffix '04' directly indicates the 400V rating.

Does the KBU1004G require a heatsink in typical 10A operation?

The KBU1004G has a junction-to-case thermal resistance (RθJC) of 2.2°C/W and a maximum junction temperature of 150°C. At 10A average forward current and 1.1V forward drop, power dissipation is ~11W. Without forced air or a heatsink, ambient temperatures above ~40°C may exceed safe junction limits. A modest heatsink or ≥10 cm² copper pour is recommended. The KBU1004G datasheet specifies RθJA = 25°C/W for still air, confirming active thermal management is advisable for sustained full-load operation.

Is the KBU1004G RoHS compliant and lead-free?

Yes, the KBU1004G is RoHS compliant and lead-free, as explicitly stated in the Taiwan Semiconductor datasheet (Version J2103). Its matte tin-plated leads meet J-STD-002 solderability requirements, and the molding compound complies with UL 94V-0 flammability standards. The device also passes JESD201 Class 1A whisker testing, confirming suitability for long-life, high-reliability applications where tin whisker formation must be mitigated. This compliance applies to all units shipped under standard ordering code KBU1004G.

What is the marking code printed on the KBU1004G package?

The KBU1004G is marked "KBU1004G" on its case, followed by date code (YWW format) and factory code (F), per the official marking diagram in the Taiwan Semiconductor datasheet. This marking confirms the exact variant and enables traceability. No abbreviated or alternate markings (e.g., "1004G" alone) are used - the full part number "KBU1004G" appears on every unit, distinguishing it from other members of the KBU100xG family such as KBU1003G (200V) or KBU1005G (600V).

Can the KBU1004G be used in place of the KBU1006G (800V) in a 230VAC design?

No - while the KBU1004G (400V VRRM) is sufficient for nominal 230VAC operation (peak ≈325V), it does not provide adequate margin for line surges, lightning transients, or abnormal conditions where voltages may exceed 400V. The KBU1006G (800V) is specified for such higher-stress environments. Substituting KBU1004G for KBU1006G risks reverse breakdown and catastrophic failure. Always select VRRM ≥1.5× peak line voltage plus transient allowance; for robust 230VAC designs, 600V or higher is preferred.