BU406 Equivalent & Substitute Parts

Part Overview

The BU406 is an NPN bipolar junction transistor (BJT) manufactured by STMicroelectronics, designed for general-purpose switching and amplification applications. The device features a maximum collector current of 7 A, collector-emitter breakdown voltage of 200 V, and maximum power dissipation of 60 W in a Through Hole TO-220-3 package. The BU406 is classified as obsolete, necessitating identification of active equivalent parts to maintain design continuity and ensure long-term component availability for new production and field replacements.

Substiute Parts

BU406

STMicroelectronicsIn Stock: 105431BU406 Datasheet

Current PartRFQ

BU406G

onsemiIn Stock: 1477BU406G Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BU406 is determined by electrical and mechanical parameter equivalence across the following criteria:

Electrical Parameters (Critical for Functional Compatibility):

• Transistor Type: NPN configuration
• Current - Collector (Ic) (Max): 7 A
• Voltage - Collector Emitter Breakdown (Max): 200 V
• Vce Saturation (Max) @ Ib, Ic: 1 V @ 500 mA, 5 A
• Current - Collector Cutoff (Max): 5 mA
• Power - Max: 60 W
• Frequency - Transition: 10 MHz

Mechanical Parameters (Required for Physical Compatibility):

• Package / Case: TO-220-3
• Mounting Type: Through Hole

Compliance Parameters (Required for Regulatory Compatibility):

• RoHS Status: ROHS3 Compliant
• REACH Status: REACH Unaffected

The BU406G from onsemi meets all electrical, mechanical, and compliance requirements and qualifies as a direct substitute.

Parameter Comparison

Engineering Selection Recommendations

The BU406G from onsemi is a direct electrical and mechanical equivalent to the obsolete BU406 from STMicroelectronics. Both devices share identical electrical specifications across all critical parameters including collector current, breakdown voltage, saturation characteristics, power rating, and transition frequency. Both are packaged in TO-220-3 Through Hole configuration and comply with ROHS3 and REACH regulatory requirements.

The primary distinction between the two parts is product status: the BU406 is obsolete, while the BU406G is active. The BU406G offers extended operating temperature range (−65°C to 150°C versus 150°C maximum for the BU406) and is supplied in Tube packaging. Selection of the BU406G ensures component availability for current and future production requirements while maintaining full functional and physical compatibility with existing BU406 designs.

Frequently Asked Questions (FAQ)

Q: Can the BU406G be used as a direct replacement for the BU406 in existing designs?

A: Yes. The BU406G meets all electrical and mechanical specifications of the BU406. Both devices are NPN transistors with identical maximum collector current (7 A), breakdown voltage (200 V), power dissipation (60 W), and TO-220-3 package configuration. No circuit modifications are required.

Q: What is the primary reason for substituting the BU406?

A: The BU406 is classified as obsolete. The BU406G from onsemi is an active equivalent part that provides long-term component availability and supply chain continuity.

Q: Are there any differences in operating temperature ranges between the BU406 and BU406G?

A: The BU406G supports an extended operating temperature range of −65°C to 150°C, compared to the BU406 maximum of 150°C. This extended range does not affect compatibility in applications operating within the BU406 specification envelope.

Q: Do both parts comply with environmental and regulatory standards?

A: Yes. Both the BU406 and BU406G are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: Are there packaging differences between the BU406 and BU406G?

A: The BU406G is supplied in Tube packaging, while the original BU406 packaging is not specified in the provided data. Both devices use the same TO-220-3 Through Hole package configuration for circuit board mounting.

Q: What are the critical electrical parameters that define substitution compatibility?

A: Substitution compatibility is determined by matching transistor type (NPN), maximum collector current (7 A), collector-emitter breakdown voltage (200 V), saturation voltage (1 V @ 500 mA, 5 A), collector cutoff current (5 mA), maximum power dissipation (60 W), and transition frequency (10 MHz).