BUY69A Equivalent & Substitute Parts

Part Overview

The BUY69A is an NPN bipolar junction transistor manufactured by STMicroelectronics, designed for high-voltage, high-current applications. This device features a 400 V collector-emitter breakdown voltage rating and 10 A maximum collector current capability, housed in a TO-3 chassis mount package. The BUY69A is classified as obsolete, necessitating identification of equivalent substitute components for ongoing design requirements and production continuity.

Substiute Parts

BUY69A

STMicroelectronicsIn Stock: 2214BUY69A Datasheet

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2N6251

Microchip TechnologyIn Stock: 11232N6251 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the BUY69A is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Transistor type must be NPN
• Collector current rating must equal or exceed 10 A
• Collector-emitter breakdown voltage must equal or exceed 400 V
• Power dissipation capability must equal or exceed 100 W
• Package type must be TO-3 or equivalent mechanical form factor

Mechanical Compatibility Criteria:

• Package designation: TO-204AA (TO-3)
• Mounting configuration: Chassis Mount or Through Hole compatible with TO-3 footprint

The 2N6251 is identified as a substitute part based on matching transistor type (NPN), collector current rating (10 A), and package form factor (TO-204AA/TO-3). However, this substitute exhibits reduced electrical performance in voltage and power ratings compared to the main part.

Parameter Comparison

Engineering Selection Recommendations

Primary Consideration: Product Status

The BUY69A is classified as obsolete. The 2N6251 is an active product from Microchip Technology, providing supply continuity for applications requiring NPN transistors in TO-3 packaging.

Electrical Performance Trade-offs

The 2N6251 substitute operates at a reduced collector-emitter breakdown voltage (350 V versus 400 V) and significantly reduced maximum power dissipation (6 W versus 100 W). These reductions must be evaluated against specific application voltage and thermal requirements.

Compliance Considerations

The BUY69A meets ROHS3 compliance requirements. The 2N6251 is RoHS non-compliant. Applications subject to RoHS regulatory requirements must account for this compliance difference.

Package Compatibility

Both devices utilize the TO-204AA (TO-3) package form factor, ensuring mechanical and thermal interface compatibility with existing PCB layouts and heat sink mounting configurations.

Frequently Asked Questions (FAQ)

Q: Can the 2N6251 directly replace the BUY69A in all applications?

A: Direct replacement is limited to applications where the collector-emitter voltage does not exceed 350 V and power dissipation remains below 6 W. Applications utilizing the full 400 V or 100 W ratings of the BUY69A require alternative substitutes or circuit redesign.

Q: Are the TO-3 and TO-204AA packages mechanically identical?

A: TO-204AA and TO-3 designations refer to the same physical package form factor. Both devices are compatible with standard TO-3 mounting hardware and thermal interfaces.

Q: What is the impact of the RoHS compliance difference?

A: The BUY69A is ROHS3 compliant; the 2N6251 is not. Applications subject to RoHS directives (EU 2011/65/EU or equivalent) must use ROHS3-compliant alternatives. The BUY69A remains the compliant choice where regulatory requirements apply.

Q: How do the DC current gain specifications compare?

A: The BUY69A specifies minimum hFE of 15 at 2.5 A and 10 V. The 2N6251 specifies minimum hFE of 6 at 10 A and 3 V. These measurements occur at different operating points and reflect different transistor characteristics.

Q: Is the 2N6251 suitable for high-frequency applications?

A: The BUY69A specifies a transition frequency of 10 MHz. The 2N6251 transition frequency is not provided in the available specifications. Frequency-dependent applications require confirmation of the 2N6251 transition frequency against specific circuit requirements.

Q: What thermal considerations apply to the 2N6251 as a substitute?

A: The 2N6251 maximum power rating of 6 W is substantially lower than the BUY69A 100 W rating. Applications requiring sustained power dissipation above 6 W necessitate alternative components or circuit modifications to reduce power dissipation.