BUT12A Equivalent & Substitute Parts

Part Overview

The BUT12A is an NPN bipolar junction transistor manufactured by onsemi, rated for 450 V collector-emitter breakdown voltage and 8 A maximum collector current in a TO-220-3 through-hole package. This device is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The 100 W power dissipation rating and high voltage capability position this transistor for high-power switching applications in industrial and consumer electronics.

Substiute Parts

BUT12A

onsemiIn Stock: 16602BUT12A Datasheet

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BUJ105A,127

WeEn SemiconductorsIn Stock: 835BUJ105A,127 Datasheet

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ST13007

STMicroelectronicsIn Stock: 1296ST13007 Datasheet

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ST13007D

STMicroelectronicsIn Stock: 680301ST13007D Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the BUT12A is determined by the following critical parameters: NPN transistor type, 8 A maximum collector current, through-hole mounting configuration, and TO-220-3 package compatibility. The substitute parts identified—BUJ105A,127, ST13007, and ST13007D—share the same collector current rating and package type, enabling direct functional replacement in circuit applications.

The primary distinction among substitutes relates to voltage rating. The BUT12A operates at 450 V maximum breakdown voltage, while the substitute parts operate at 400 V maximum breakdown voltage. This 50 V differential represents a design margin reduction and must be evaluated against specific application requirements. All substitute parts maintain the same 8 A current capability, 150°C operating temperature, and through-hole mounting configuration as the original device.

Parameter Comparison

Engineering Selection Recommendations

The ST13007D manufactured by STMicroelectronics represents the primary substitute for the BUT12A. This device maintains full compatibility with the original part across all critical parameters: 8 A collector current, TO-220-3 package, 150°C operating temperature, and through-hole mounting. The ST13007D carries ROHS3 compliance and REACH unaffected status, supporting modern regulatory requirements. With 680,200 units in stock, supply continuity is assured.

The ST13007 (non-D variant) from STMicroelectronics provides an alternative substitute with identical electrical ratings and package configuration. This part also maintains active product status and ROHS3 compliance.

The BUJ105A,127 from WeEn Semiconductors functions as a substitute with equivalent current and package specifications. This device carries RoHS compliance certification and maintains active product status. The BUJ105A,127 is packaged in tube format and offers 743 units in current inventory.

All three substitute parts operate at 400 V maximum breakdown voltage compared to the BUT12A's 450 V rating. Applications operating near the upper voltage limits of the original specification require circuit analysis to confirm adequate design margin with the reduced voltage rating. The power dissipation rating reduction from 100 W to 80 W in substitute parts necessitates thermal management review for high-power applications.

Frequently Asked Questions (FAQ)

Q: Can the ST13007D directly replace the BUT12A in existing circuit designs?

A: The ST13007D maintains electrical and mechanical compatibility with the BUT12A across collector current (8 A), operating temperature (150°C), and package type (TO-220-3). The voltage rating differential (400 V versus 450 V) requires application-specific evaluation to confirm adequate design margin.

Q: What is the primary difference between ST13007 and ST13007D?

A: Both devices share identical electrical ratings and package specifications. The primary differences are in saturation voltage characteristics and collector cutoff current specifications. ST13007D exhibits 2V saturation voltage at 2A/8A conditions, while ST13007 exhibits 3V under the same conditions.

Q: Are all substitute parts RoHS compliant?

A: Yes. ST13007D and ST13007 carry ROHS3 compliance certification. BUJ105A,127 carries RoHS compliance certification. The original BUT12A does not specify RoHS status.

Q: What is the impact of the 20 W power dissipation reduction in substitute parts?

A: Substitute parts are rated at 80 W maximum power dissipation compared to the BUT12A's 100 W rating. Applications requiring sustained power dissipation above 80 W require thermal design modification or alternative component selection.

Q: Are the TO-220-3 and TO-220AB packages mechanically compatible?

A: The BUJ105A,127 is supplied in TO-220AB package format. While both TO-220-3 and TO-220AB are through-hole TO-220 variants, mechanical compatibility depends on specific PCB footprint design. Standard TO-220-3 footprints accommodate TO-220AB devices.

Q: Which substitute part offers the best supply availability?

A: ST13007D provides the highest inventory level with 680,200 units in stock, ensuring long-term supply continuity for production requirements.