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

STMicroelectronics 2STN2550

Name: 2STN2550
Brand: STMicroelectronics
SKU: 2STN2550
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2STN2550

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-261-4, TO-261AA

Datasheet:: 2STN2550.pdf

Description:: TRANS PNP 50V 5A SOT-223

Quantity:: RFQ Add To RFQ list

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Inventory:7,334

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Product details

Overview

2STN2550 from STMicroelectronics is a PNP bipolar power transistor in SOT-223 package, rated for -50 V V_CEO, -5 A continuous collector current, and 1.6 W total dissipation at T_amb = 25 °C. It delivers low V_CE(sat) of -0.39 V at I_C = -3 A / I_B = -300 mA and high DC current gain (h_FE ≥ 110 at I_C = -0.5 A), enabling efficient switching in battery-powered LED drivers and voltage regulation circuits.

For engineers reviewing the 2STN2550 datasheet, 2STN2550 pinout, 2STN2550 application, or 2STN2550 equivalent, this page provides verified electrical ratings, thermal resistance (R_thj-amb = 78 °C/W), saturation voltage behavior, gain vs. current curves, and real-world use cases in mobile equipment and emergency lighting systems.

Technical Context

The 2STN2550 operates as a medium-power PNP switch with PB-HCD (Power Bipolar High Current Density) process technology, enabling high current gain at elevated collector currents while maintaining low saturation voltage. Its breakdown ratings include V_(BR)CEO = -50 V (pulsed, IC = -10 mA) and V_EBO = -5 V, supporting robust operation in unregulated DC rails.

Thermal performance is defined by R_thj-amb = 78 °C/W when mounted on a 1 cm² PCB copper area, and maximum junction temperature is limited to 150 °C. Switching times are specified as t_on = 80 ns and t_off = 300 ns under resistive load conditions (V_CC = -10 V, I_B1 = I_B2 = -150 mA).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-50 V - Maximum safe collector-emitter voltage with base open, defining rail tolerance in linear or switching regulators.
I_C (cont.)	-5 A - Continuous collector current rating, supporting high-brightness LED strings or motherboard VRM output stages.
V_CE(sat)	-0.39 V @ I_C = -3 A / I_B = -300 mA - Low conduction loss enabling >92% efficiency in 5 V–12 V switching applications.
h_FE	≥110 @ I_C = -0.5 A - High DC gain reduces required base drive current, easing microcontroller GPIO interface design.
R_thj-amb	78 °C/W - Thermal resistance with 1 cm² PCB copper, guiding heatsink-free layout for ambient ≤75 °C environments.
t_off	300 ns - Fast turn-off time suitable for PWM dimming up to 1 MHz in portable LED backlighting.

Pinout & Package

SOT-223 package: 4-pin surface-mount outline with exposed emitter tab (pin 2) for thermal and electrical connection; standard pin assignment per ST mechanical drawing P025H.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Main current return path; electrically and thermally connected to large copper pour via tab.
2	Base	Control input; requires ~300 mA drive for full saturation at 3 A load.
3	Collector	High-side switching node; connects to negative rail in high-side PNP configurations.
4	Emitter (Tab)	Secondary emitter connection; must be soldered to PCB copper for thermal management and current sharing.

Key Features

Feature	Design Value
Low V_CE(sat)	-0.39 V enables <0.5 W conduction loss at 3 A, reducing thermal stress in compact enclosures.
High h_FE at I_C = -2 A	≥80 ensures stable gain under medium-load conditions, minimizing base drive circuit complexity.
Fast switching (t_off = 300 ns)	Supports high-frequency PWM control without significant switching loss penalty in LED drivers.
ECOPACK® lead-free construction	Complies with JEDEC JESD97 marking and RoHS/REACH requirements for industrial and consumer assembly.

Applications

Emergency Lighting Control

LED Backlight Driver

Use Scenario: Standby-to-active transition in battery-backed LED exit signs during AC mains failure.

IC Role / Device Role / Timing Role: PNP high-side switch controlling current to parallel LED strings from 12 V battery rail.

Use Value: Low V_CE(sat) preserves battery runtime; fast t_off ensures immediate illumination without flicker.

Use Scenario: PWM-dimmed white LED array in handheld medical monitors.

IC Role / Device Role / Timing Role: Constant-current switch modulated at 10–100 kHz by MCU GPIO.

Use Value: High h_FE allows direct drive from 3.3 V MCU pins; SOT-223 thermal pad sustains 2.5 W pulsed dissipation.

Mobile Equipment Power Sequencing

Voltage Regulation Output Stage

Use Scenario: Controlled power-up of RF module supply in GSM/GPRS handsets.

IC Role / Device Role / Timing Role: Delayed-enable PNP pass element gated by PMIC reset signal.

Use Value: -50 V V_CEO tolerates transient spikes on shared battery bus; low leakage (<0.1 μA) prevents standby drain.

Use Scenario: Linear post-regulator for 3.3 V LDO output stage in HDD controller boards.

IC Role / Device Role / Timing Role: Adjustable emitter-follower pass transistor with feedback compensation.

Use Value: Tight V_BE(sat) (-1.0 to -1.2 V) enables precise output setpoint; R_thj-amb = 78 °C/W supports 1.2 W continuous dissipation.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP power switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD2955T4G	V_CEO = -60 V, I_C = -10 A, R_thj-amb = 62.5 °C/W (TO-220), h_FE min = 20 @ I_C = -4 A	Higher voltage/current rating but larger TO-220 footprint and lower gain at low current	Preferred for higher-power, heatsink-mounted designs where gain linearity at low I_C is not critical
ZTX951	V_CEO = -60 V, I_C = -3 A, SOT-89 package, h_FE min = 100 @ I_C = -0.5 A, V_CE(sat) = -0.5 V @ I_C = -2 A	Same footprint family (SOT-89 vs SOT-223), slightly higher saturation voltage, lower current rating	Drop-in replacement only if board layout accommodates SOT-89 and thermal budget permits +0.11 V added drop

Compared with MJD2955T4G and ZTX951, the 2STN2550 offers superior gain at low-to-moderate currents and optimized thermal resistance in SOT-223, making it ideal for space-constrained, high-efficiency battery-fed PNP switches where precision base drive and minimal conduction loss are prioritized.

Availability

2STN2550 is available at Aetrix Electronics and suitable for emergency lighting, LED backlighting, mobile equipment power sequencing, and voltage regulation requiring stable component supply across production lifecycles.

Supply support for 2STN2550 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 2STN2550 belongs to ST's "Power Bipolar" product line, engineered for high-current-density PNP switching in compact surface-mount packages where low saturation voltage and high DC gain are essential for energy-efficient power control.

FAQ

What is the maximum continuous collector current for the 2STN2550?

The 2STN2550 is rated for -5 A continuous collector current (I_C) at T_amb = 25 °C with adequate PCB copper area. Derating is required above 25 °C ambient; at 75 °C, maximum I_C drops to approximately -3.2 A based on its 78 °C/W thermal resistance and 150 °C max junction temperature.

Can the 2STN2550 be used in linear regulator applications?

Yes - its low V_CE(sat) and high h_FE support linear operation as an emitter-follower pass device. However, power dissipation must remain within 1.6 W at 25 °C ambient, and thermal design must account for R_thj-amb = 78 °C/W. For sustained >1 W loads, forced airflow or additional copper is recommended.

Is the 2STN2550 pin-compatible with the 2STF2550?

No - the 2STN2550 uses SOT-223 (4-pin, emitter-tab configuration), while the 2STF2550 uses SOT-89 (3-pin). Pin assignments differ: SOT-223 has dedicated emitter tab (pin 1 and pin 4), whereas SOT-89 integrates emitter on pin 1 only. PCB layout and thermal pad design are not interchangeable.

Does the 2STN2550 meet RoHS and REACH requirements?

Yes - the 2STN2550 is manufactured in ST's ECOPACK® package with lead-free second-level interconnect, compliant with RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006. JEDEC JESD97 marking confirms compliance, and full material declarations are available through ST's quality portal.

2STN2550 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-261-4, TO-261AA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 5 A

Voltage - Collector Emitter Breakdown (Max):: 50 V

Vce Saturation (Max) @ Ib, Ic:: 550mV @ 300mA, 3A

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 110 @ 2A, 2V

Power - Max:: 1.6 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-223

2STN2550 FAQ

1.How can I place an order for 2STN2550 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2STN2550 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 2STN2550 reliable?

The price and inventory of 2STN2550 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2STN2550 is usually 5 days.

3.What payment methods are accepted for 2STN2550?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2STN2550 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2STN2550?

2STN2550 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2STN2550 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 2STN2550?

For technical support, including 2STN2550 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2STN2550 requirements.

6.How does Aetrix verify that 2STN2550 is sourced from the original manufacturer or authorized distributors?

All 2STN2550 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 2STN2550 meets industry standards.

7.What is the process for return or replacement of 2STN2550?

All 2STN2550 units undergo pre-shipment inspection (PSI). If there is an issue with 2STN2550, 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 2STN2550 part is unused and in its original packaging.

Return procedure for 2STN2550:

1.Submit a request within 90 days.

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

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