BUT12ATU Equivalent & Substitute Parts

Part Overview

The BUT12ATU 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 and substitute parts necessary for ongoing design support and production continuity. The 100 W power rating and high voltage capability position this transistor for high-power switching applications requiring robust voltage handling.

Substiute Parts

BUT12ATU

onsemiIn Stock: 880BUT12ATU Datasheet

Current PartRFQ

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 BUT12ATU is determined by the following critical parameters:

Primary Substitution Criteria:

• Transistor Type: NPN configuration required
• Maximum Collector Current: 8 A minimum
• Collector-Emitter Breakdown Voltage: 400 V or higher
• Power Dissipation: 80 W or higher
• Mounting Type: Through Hole
• Package: TO-220-3 or compatible TO-220 variants
• Operating Temperature: 150°C maximum junction temperature

The substitute parts listed (BUJ105A,127, ST13007, and ST13007D) meet these electrical and mechanical requirements. All substitutes maintain the same collector current rating of 8 A and operate at the same maximum junction temperature of 150°C. Voltage ratings of 400 V in the substitute parts remain within acceptable operating margins for applications designed for the 450 V rated BUT12ATU. All substitutes are housed in TO-220-3 or compatible TO-220 packages suitable for through-hole mounting.

Parameter Comparison

Engineering Selection Recommendations

ST13007D (STMicroelectronics) is the primary substitute for the BUT12ATU. This part is active in production, ROHS3 compliant, and maintains full electrical compatibility with the original device. The 400 V breakdown voltage rating is suitable for applications designed around the 450 V rated BUT12ATU, as the 50 V margin provides adequate design headroom in typical switching applications.

ST13007 (STMicroelectronics) serves as an alternative substitute with identical electrical specifications to the ST13007D. Both STMicroelectronics parts offer superior long-term availability compared to the obsolete BUT12ATU and carry REACH compliance certification.

BUJ105A,127 (WeEn Semiconductors) is a functional substitute meeting all primary electrical and mechanical requirements. This part maintains active production status and is available in tube packaging. The 400 V breakdown voltage and 80 W power rating satisfy the substitution criteria established for the BUT12ATU.

Selection between these three substitutes should be based on supply chain availability, cost considerations, and existing qualification status within your organization. All three parts are electrically interchangeable within the specified parameter ranges.

Frequently Asked Questions (FAQ)

Q: Can the ST13007D directly replace the BUT12ATU in existing designs?

A: Yes. The ST13007D maintains the same collector current rating (8 A), operating temperature (150°C), and TO-220-3 package configuration as the BUT12ATU. The 400 V breakdown voltage is lower than the original 450 V rating but remains within acceptable operating margins for applications designed for the BUT12ATU.

Q: What is the significance of the 50 V difference in breakdown voltage between the BUT12ATU (450 V) and the substitute parts (400 V)?

A: The 50 V difference represents a 11% reduction in maximum rated voltage. For applications operating below 400 V, this difference is not a limiting factor. Applications requiring operation above 400 V should retain the original BUT12ATU or seek alternative parts with higher voltage ratings.

Q: Are all substitute parts available in the same TO-220-3 package?

A: Yes. The BUJ105A,127, ST13007, and ST13007D are all housed in TO-220-3 or compatible TO-220 packages suitable for through-hole mounting. Pin configurations are identical, allowing direct socket replacement.

Q: What is the difference between ST13007 and ST13007D?

A: Both parts are manufactured by STMicroelectronics with identical electrical ratings and package configurations. The primary differences are in saturation voltage characteristics and collector cutoff current specifications. Both are active products with ROHS3 compliance and REACH certification.

Q: Why is the BUT12ATU listed as obsolete?

A: The obsolete status indicates that onsemi has discontinued production of this part. Existing inventory may be available through authorized distributors, but long-term supply cannot be guaranteed. Transition to active substitute parts is recommended for new designs and ongoing production.

Q: Can the 80 W power rating of the substitute parts replace the 100 W rating of the BUT12ATU?

A: The 80 W rating of the substitute parts is lower than the original 100 W specification. Applications operating at or near the 100 W maximum dissipation limit should be re-evaluated with thermal analysis to confirm the 80 W substitutes are adequate. Most practical applications operate below maximum power ratings and will not be affected by this difference.

Q: Are there compliance or certification differences between the substitute parts?

A: The STMicroelectronics parts (ST13007 and ST13007D) carry ROHS3 compliance certification. The WeEn Semiconductors BUJ105A,127 does not specify RoHS status in the provided data. All parts are classified under the same ECCN (EAR99) and HTSUS codes, indicating equivalent regulatory treatment.