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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

STMicroelectronics 2STC5949

Name: 2STC5949
Brand: STMicroelectronics
SKU: 2STC5949
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2STC5949

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-264-3, TO-264AA

Datasheet:: 2STC5949.pdf

Description:: TRANS NPN 250V 17A TO-264

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2STC5949 from STMicroelectronics is a high-power NPN epitaxial planar bipolar transistor designed for linear audio amplifier output stages, featuring V_CEO = 250 V, I_C = 17 A, P_TOT = 220 W at T_c = 25 °C, f_T = 25 MHz, and R_thj-case = 0.568 °C/W - deployed in TO-264 package for high-fidelity audio power amplification.

For engineers reviewing the 2STC5949 datasheet, 2STC5949 pinout, 2STC5949 application, or 2STC5949 equivalent, key selection considerations include safe operating area (SOA) at 125 °C, gain linearity under large-signal conditions, complementary pairing with 2STA2121, and thermal derating behavior per Figure 3.

Technical Context

This device implements BiT-LA (Bipolar transistor for linear amplifier) technology to optimize h_FE linearity across collector current (35–160 at I_C = 1–7 A), minimizing harmonic distortion in Class AB audio output stages. It supports pulsed operation up to 34 A (t_P < 5 ms) and maintains V_CE(sat) ≤ 3 V at I_C = 8 A / I_B = 800 mA.

The transistor is fully characterized at T_case = 125 °C, with guaranteed V_(BR)CEO ≥ 250 V and junction temperature limit of 150 °C. Its TO-264 metal package enables direct heatsink mounting and low thermal resistance (0.568 °C/W junction-to-case).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	250 V - supports rail voltages up to ±100 V in push-pull audio output stages without breakdown
I_C	17 A continuous - delivers >200 W RMS into 4 Ω loads with proper heatsinking
P_TOT	220 W at T_c = 25 °C - requires active cooling or large heatsink for sustained full-power operation
f_T	25 MHz - ensures stable wideband response up to 100 kHz with minimal phase shift in feedback loops
R_thj-case	0.568 °C/W - enables junction temperature rise of ≤85 °C above case at 150 W dissipation
h_FE	35–160 (I_C = 1–7 A) - provides predictable bias stability and low THD in linear Class AB designs

Pinout & Package

Package: TO-264 - isolated metal flange package with three leads (Collector, Base, Emitter), designed for direct bolt-down heatsink mounting and high-power thermal management.

Pin/Terminal	Circuit Role	Design Meaning
Collector (tab)	Main current sink terminal	Electrically connected to metal flange; must be insulated from heatsink unless common-collector configuration is used
Base	Current-controlled input	Drives 800 mA base current to sustain 8 A collector conduction; requires low-impedance driver stage
Emitter	Current source reference	Provides low-impedance return path; often tied to ground or negative rail in single-ended output topologies

Key Features

Feature	Design Value
BiT-LA process technology	Optimized h_FE linearity over I_C, reducing 2nd/3rd harmonic distortion in audio output stages
125 °C characterization	Guaranteed electrical parameters at elevated case temperature - simplifies thermal design for enclosed amplifiers
Complementary pairing	Matched performance with 2STA2121 (PNP) - enables symmetric push-pull output stage construction
ECOPACK® compliance	Lead-free second-level interconnect - meets RoHS and JEDEC JESD97 marking requirements for industrial use

Applications

High-Fidelity Audio Amplifier

Professional PA Output Stage

Use Scenario: Discrete Class AB output stage in stereo integrated amplifier delivering 150 W/channel into 8 Ω.

IC Role / Device Role / Timing Role: Main NPN output transistor in push-pull pair, handling peak current swing and heat dissipation.

Use Value: V_CEO = 250 V and SOA curve support ±85 V rails; R_thj-case = 0.568 °C/W enables compact heatsink design.

Use Scenario: High-reliability output module in touring-grade powered loudspeaker with dual 2STC5949 per channel.

IC Role / Device Role / Timing Role: Primary current-handling device in quasi-complementary output topology.

Use Value: 17 A continuous rating and 34 A pulsed capability handle dynamic program peaks without thermal runaway.

Studio Monitor Power Section

Instrument Amplifier Output

Use Scenario: Near-field studio monitor requiring ultra-low distortion below 0.05% THD+N at full rated power.

IC Role / Device Role / Timing Role: Linear amplifier output transistor biased for optimal h_FE linearity region per BiT-LA design.

Use Value: Measured h_FE consistency (35–160) across I_C minimizes crossover distortion and improves transient fidelity.

Use Scenario: Guitar/bass amplifier output stage where ruggedness and thermal stability are critical during extended live use.

IC Role / Device Role / Timing Role: Final power gain device in cathode-follower-driven output section.

Use Value: Junction temperature rating of 150 °C and SOA validation at 125 °C ensure reliability under sustained clipping conditions.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-power linear amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2STA2121	Complementary PNP counterpart; identical V_CEO, I_C, and f_T; slightly lower h_FE min (25 vs. 35)	Required for matched push-pull pairs; not interchangeable as direct replacement	Select only when building complementary output stages with 2STC5949
MJE15030G	Lower V_CEO (200 V), higher R_thj-case (0.83 °C/W), same TO-264 package	Suitable for ≤±70 V rail systems; requires larger heatsink for equivalent power	Choose if lower voltage rails and legacy design compatibility are prioritized over maximum headroom

Compared with 2STA2121, this part serves as the NPN half of a matched pair rather than a drop-in substitute; versus MJE15030G, it offers +50 V breakdown margin and 31% better thermal resistance - critical for high-rail, high-fidelity audio designs.

Availability

2STC5949 is available at Aetrix Electronics and suitable for high-fidelity audio amplifiers, professional PA systems, and studio monitor power sections requiring stable component supply and long-term BOM continuity.

Supply support for 2STC5949 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, digital, and mixed-signal ICs and discrete devices for industrial, automotive, and consumer markets.

The 2STC5949 belongs to ST's high-power linear bipolar transistor family, engineered specifically for low-distortion audio power amplification using BiT-LA process technology.

FAQ

Is 2STC5949 still in active production?

No - STMicroelectronics has marked 2STC5949 as Obsolete Product(s) per its official datasheet revision history (Rev 4, Nov 2008). However, Aetrix Electronics maintains legacy inventory with full traceability and supports long-life designs through controlled distribution and BOM continuity programs.

What is the safe operating area (SOA) limitation at 100 °C case temperature?

Per Figure 2 in the datasheet, the SOA at T_c = 100 °C is derated to approximately 60% of the 25 °C curve - limiting continuous I_C to ~10 A at V_CE = 50 V, and imposing stricter pulse-width/duty-cycle constraints above 100 V. Derating follows the curve in Figure 3.

Can 2STC5949 be used in switching applications?

It is not optimized for switching: V_CE(sat) = 3 V at I_C = 8 A indicates significant conduction loss, and f_T = 25 MHz reflects small-signal AC performance, not switching speed. Its SOA and thermal design target linear operation - use dedicated switching transistors (e.g., STGPxxH series) instead.

How does BiT-LA technology improve audio performance compared to standard planar processes?

BiT-LA modifies doping profiles and junction geometry to flatten h_FE vs. I_C curves - reducing gain variation across signal swing. This directly lowers harmonic distortion (especially 2nd order) in Class AB output stages, as confirmed by measured THD data in ST's application notes for similar BiT-LA devices.

2STC5949 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-264-3, TO-264AA

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 17 A

Voltage - Collector Emitter Breakdown (Max):: 250 V

Vce Saturation (Max) @ Ib, Ic:: 3V @ 800mA, 8A

Current - Collector Cutoff (Max):: 5µA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 80 @ 1A, 5V

Power - Max:: 220 W

Frequency - Transition:: 25MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-264

2STC5949 FAQ

1.How can I place an order for 2STC5949 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2STC5949 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 2STC5949 reliable?

The price and inventory of 2STC5949 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2STC5949 is usually 5 days.

3.What payment methods are accepted for 2STC5949?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2STC5949 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2STC5949?

2STC5949 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2STC5949 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 2STC5949?

For technical support, including 2STC5949 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2STC5949 requirements.

6.How does Aetrix verify that 2STC5949 is sourced from the original manufacturer or authorized distributors?

All 2STC5949 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 2STC5949 meets industry standards.

7.What is the process for return or replacement of 2STC5949?

All 2STC5949 units undergo pre-shipment inspection (PSI). If there is an issue with 2STC5949, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 2STC5949 part is unused and in its original packaging.

Return procedure for 2STC5949:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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