BD438TG Equivalent & Substitute Parts

Part Overview

The BD438TG is a PNP bipolar junction transistor manufactured by onsemi, rated for 45 V collector-emitter breakdown voltage and 4 A maximum collector current. This device is packaged in TO-126 through-hole configuration and is designated as Last Time Buy status. The BD438TG delivers 36 W maximum power dissipation with a 3 MHz transition frequency, suitable for general-purpose switching and amplification applications in industrial and consumer electronics.

Due to Last Time Buy status, identifying equivalent and substitute parts ensures design continuity and supply chain reliability for ongoing production requirements.

Substiute Parts

BD438TG

onsemiIn Stock: 894BD438TG Datasheet

Current PartRFQ

MJE371G

onsemiIn Stock: 3215MJE371G Datasheet

SimilarRFQ

BD438

STMicroelectronicsIn Stock: 6538BD438 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the BD438TG is determined by the following critical parameters:

Primary Matching Criteria:

• Transistor type: PNP configuration
• Maximum collector current: 4 A or greater
• Collector-emitter breakdown voltage: 45 V or greater
• Maximum power dissipation: 36 W or greater
• Mounting type: Through Hole
• Package compatibility: TO-126 or equivalent footprint

Secondary Compatibility Factors:

• Operating temperature range: Must encompass or exceed -55°C to 150°C
• RoHS and REACH compliance status
• Moisture sensitivity level classification

Substitute parts must satisfy all primary matching criteria to ensure functional equivalence in existing circuit designs. Secondary factors confirm regulatory and environmental compliance alignment.

Parameter Comparison

Engineering Selection Recommendations

BD438 (STMicroelectronics, SOT-32-3 Package)

The BD438 from STMicroelectronics is a direct equivalent to the BD438TG with identical electrical ratings: 45 V breakdown voltage, 4 A collector current, and 36 W power dissipation. Both devices share the same base product number and transition frequency specification of 3 MHz. This part maintains Active product status, ensuring long-term availability. The SOT-32-3 package is a through-hole configuration compatible with TO-126 footprints. Full RoHS3 and REACH compliance is maintained. This substitute is suitable for direct replacement in applications where package form factor compatibility is confirmed.

MJE371G (onsemi, TO-126-3 Package)

The MJE371G is an alternative PNP transistor with 4 A collector current and 40 W power dissipation. The collector-emitter breakdown voltage is rated at 40 V, which is 5 V lower than the BD438TG specification. This part maintains Active product status and offers extended lower operating temperature range (-65°C versus -55°C). The TO-126-3 package provides direct mechanical compatibility with the BD438TG. RoHS3 and REACH compliance are confirmed. Selection of this substitute requires verification that the 40 V breakdown voltage rating is acceptable for the target application voltage requirements.

Frequently Asked Questions (FAQ)

Q: Can the MJE371G replace the BD438TG in all applications?

A: The MJE371G is electrically compatible for applications where the circuit operates at or below 40 V collector-emitter voltage. The BD438TG is rated for 45 V breakdown voltage. If the application requires the full 45 V rating, the MJE371G is not suitable. Both devices share identical 4 A collector current and through-hole TO-126 packaging.

Q: What is the difference between the BD438 (STMicroelectronics) and BD438TG (onsemi)?

A: Both devices share identical electrical specifications: 45 V breakdown voltage, 4 A collector current, 36 W power dissipation, and 3 MHz transition frequency. The primary difference is manufacturer (STMicroelectronics versus onsemi) and package designation (SOT-32-3 versus TO-126). The STMicroelectronics version maintains Active product status, while the onsemi BD438TG is Last Time Buy.

Q: Are all three parts pin-compatible?

A: The BD438TG and MJE371G both use TO-126-3 packaging with identical pin configuration. The BD438 from STMicroelectronics uses SOT-32-3 packaging, which is also a through-hole configuration but with different physical dimensions. Verify PCB footprint compatibility before selection.

Q: Do all substitute parts meet the same compliance requirements?

A: Yes. All three parts are ROHS3 Compliant and REACH Unaffected. Moisture sensitivity level is classified as 1 (Unlimited) for both onsemi devices. The STMicroelectronics BD438 does not specify moisture sensitivity level but maintains equivalent compliance certifications.

Q: Which substitute offers the longest product lifecycle?

A: Both the MJE371G (onsemi) and BD438 (STMicroelectronics) maintain Active product status, ensuring continued availability. The BD438TG is designated Last Time Buy, indicating limited future availability. For new designs or long-term production requirements, selection of an Active-status part is recommended.

Q: What are the key electrical differences between the three parts?

A: The BD438TG and BD438 (STMicroelectronics) are electrically identical with 45 V breakdown voltage and 36 W power rating. The MJE371G has a 40 V breakdown voltage and 40 W power rating. All three devices support 4 A collector current. Transition frequency is specified as 3 MHz for both onsemi and STMicroelectronics versions; the MJE371G does not specify this parameter.