2ST5949 Equivalent & Substitute Parts

Part Overview

The 2ST5949 is an NPN bipolar junction transistor manufactured by STMicroelectronics, designed for high-power applications requiring 250V collector-emitter breakdown voltage and 17A maximum collector current. This device is packaged in a TO-3 chassis mount configuration and rated for 250W maximum power dissipation. The 2ST5949 is classified as obsolete, making identification of functionally equivalent substitute components necessary for ongoing system support and new design implementations.

Substiute Parts

2ST5949

STMicroelectronicsIn Stock: 8032ST5949 Datasheet

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MJ21194G

onsemiIn Stock: 1295MJ21194G Datasheet

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MJ21196G

onsemiIn Stock: 2153MJ21196G Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 2ST5949 are identified based on the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Transistor Type: NPN (required match)
• Voltage - Collector Emitter Breakdown (Max): 250V (required match)
• Power - Max: 250W (required match)
• Package / Case: TO-204AA, TO-3 (required match for mechanical fit)

Acceptable Parameter Variations:

• Current - Collector (Ic) (Max): Substitute parts rated at 16A are acceptable for applications requiring maximum 16A operation; the 2ST5949 rated at 17A provides marginal additional capacity
• Frequency - Transition: Substitute parts rated at 4MHz are acceptable; the 2ST5949 rated at 25MHz provides higher frequency capability
• Operating Temperature: Substitute parts with extended temperature range (-65°C to 200°C) provide broader operational envelope than the 2ST5949 (150°C maximum)
• DC Current Gain (hFE): Variations in minimum gain specifications reflect different design characteristics but do not preclude substitution when electrical ratings align

The substitute parts MJ21194G and MJ21196G meet all critical electrical and mechanical compatibility requirements while offering active product status and extended operational temperature ranges.

Parameter Comparison

Engineering Selection Recommendations

MJ21194G and MJ21196G Suitability:

Both MJ21194G and MJ21196G substitute parts satisfy the core electrical requirements for 2ST5949 replacement applications. These devices maintain identical voltage and power ratings (250V, 250W) and are housed in compatible TO-3 packages. The substitute parts are manufactured by onsemi and carry active product status, ensuring ongoing availability and supply chain continuity.

Compliance and Regulatory Alignment:

All three devices—the 2ST5949, MJ21194G, and MJ21196G—are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory standards for electronic component manufacturing and distribution.

Operational Considerations:

Applications designed for the 2ST5949 operating at collector currents up to 16A are directly compatible with MJ21194G or MJ21196G substitutes. Applications requiring the full 17A capability of the 2ST5949 require design review to confirm operation within the 16A maximum rating of substitute parts. The extended operating temperature range of substitute parts (-65°C to 200°C) provides enhanced thermal margin compared to the 2ST5949 (150°C maximum junction temperature).

Frequently Asked Questions (FAQ)

Q: Can MJ21194G or MJ21196G directly replace 2ST5949 in existing designs?

A: Direct replacement is possible when the application operates at collector currents of 16A or less. The identical voltage rating (250V), power rating (250W), and TO-3 package ensure mechanical and electrical compatibility. Applications requiring the full 17A capability of the 2ST5949 require design verification.

Q: What is the difference between MJ21194G and MJ21196G?

A: Both devices are electrically identical with respect to the parameters provided. Both are manufactured by onsemi, carry active product status, and are rated for 250V, 16A, and 250W. Selection between these two parts may be based on inventory availability or supplier preference.

Q: Why does the 2ST5949 have a higher current rating (17A) than the substitute parts (16A)?

A: The 2ST5949 is rated for 17A maximum collector current, while MJ21194G and MJ21196G are rated for 16A. This represents a 1A difference in maximum rated current. Applications operating below 16A are unaffected by this specification difference.

Q: Are there mounting differences between the 2ST5949 and substitute parts?

A: The 2ST5949 is specified as chassis mount, while MJ21194G and MJ21196G are specified as through-hole. Both device types use the TO-3 package. Mounting method differences relate to circuit board integration approach rather than package compatibility.

Q: What is the significance of the frequency-transition rating difference?

A: The 2ST5949 is rated for 25MHz transition frequency, while substitute parts are rated for 4MHz. For applications operating below 4MHz, this difference is not limiting. Applications requiring operation above 4MHz require design review to confirm performance with substitute parts.

Q: Are the substitute parts RoHS and REACH compliant?

A: Yes. Both MJ21194G and MJ21196G are ROHS3 compliant and REACH unaffected, matching the compliance status of the 2ST5949.

Q: What is the advantage of the extended temperature range in substitute parts?

A: MJ21194G and MJ21196G operate across -65°C to 200°C, compared to the 2ST5949 maximum of 150°C. This extended range provides additional thermal margin and enables operation in wider environmental conditions.