2N4239 Equivalent & Substitute Parts

Part Overview

The 2N4239 is an NPN bipolar junction transistor (BJT) manufactured by Central Semiconductor Corp, designed for through-hole applications in the TO-39 metal can package. This device is rated for 80 V collector-emitter breakdown voltage, 3 A maximum collector current, and 6 W maximum power dissipation, with a transition frequency of 300 MHz. The 2N4239 is classified as obsolete, making identification of functionally equivalent substitute components necessary for ongoing design support and component procurement.

Substiute Parts

2N4239

Central Semiconductor CorpIn Stock: 14182N4239 Datasheet

Current PartRFQ

2N3421S

Microchip TechnologyIn Stock: 8242N3421S Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2N4239 is determined by matching the following critical electrical and mechanical parameters:

• Transistor Type: NPN configuration required
• Current Rating: Maximum collector current of 3 A or greater
• Voltage Rating: Collector-emitter breakdown voltage of 80 V or greater
• Package: TO-39 through-hole metal can package (TO-205AD)
• Operating Temperature Range: -65°C to 200°C (TJ) or compatible range
• Mounting Type: Through-hole configuration

The 2N3421S meets these substitution criteria, providing equivalent electrical performance within the specified parameter envelope while maintaining mechanical compatibility with existing PCB designs and socket configurations.

Parameter Comparison

Engineering Selection Recommendations

The 2N3421S is an active-status substitute for the obsolete 2N4239. Both devices share identical maximum collector current (3 A) and collector-emitter breakdown voltage (80 V) ratings, with matching TO-39 through-hole package specifications and operating temperature ranges (-65°C to 200°C TJ).

The 2N3421S is manufactured by Microchip Technology and maintains active product status, ensuring ongoing availability and supply chain continuity. Both components carry identical REACH and ECCN classifications (REACH Unaffected, EAR99), supporting equivalent regulatory compliance.

Differences in maximum power dissipation (2N4239: 6 W; 2N3421S: 1 W) and collector cutoff current (2N4239: 700 µA; 2N3421S: 5 µA) reflect design variations between manufacturers. Applications requiring the full 6 W power rating of the 2N4239 must evaluate whether the 1 W rating of the 2N3421S is sufficient for the intended circuit function.

Frequently Asked Questions (FAQ)

Q: Can the 2N3421S directly replace the 2N4239 in existing designs?

A: The 2N3421S provides electrical and mechanical compatibility for most applications. Both devices are NPN transistors with identical 3 A collector current and 80 V breakdown voltage ratings in TO-39 through-hole packages. However, the reduced maximum power dissipation (1 W versus 6 W) must be evaluated against circuit requirements.

Q: What are the key differences between these two devices?

A: The primary differences are manufacturer (Central Semiconductor Corp versus Microchip Technology), product status (obsolete versus active), maximum power dissipation (6 W versus 1 W), and collector cutoff current (700 µA versus 5 µA). Electrical performance for current and voltage ratings is equivalent.

Q: Is the TO-39 package identical between both parts?

A: Yes. Both the 2N4239 and 2N3421S use the TO-39-3 metal can package (TO-205AD designation), ensuring mechanical and pin compatibility for through-hole PCB applications.

Q: What is the significance of the product status difference?

A: The 2N4239 is classified as obsolete, indicating discontinued manufacturing and limited availability. The 2N3421S maintains active status, ensuring reliable supply chain access and ongoing manufacturer support.

Q: Are there compliance or regulatory differences between these parts?

A: No. Both devices carry identical REACH (REACH Unaffected) and ECCN (EAR99) classifications, supporting equivalent regulatory compliance for export and environmental standards.

Q: How does the power dissipation difference affect substitution?

A: The 2N4239 is rated for 6 W maximum power dissipation, while the 2N3421S is rated for 1 W. Applications operating at power levels between 1 W and 6 W require thermal analysis to confirm the 2N3421S can operate within safe junction temperature limits.