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

STMicroelectronics 2STN2540

Name: 2STN2540
Brand: STMicroelectronics
SKU: 2STN2540
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2STN2540

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

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

Datasheet:: 2STN2540.pdf

Description:: TRANS PNP 40V 5A SOT-223

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2STN2540 from STMicroelectronics is a PNP bipolar power transistor fabricated with PB-HCD (Power Bipolar High Current Density) technology, designed for low-voltage fast-switching applications. It delivers V_CE(sat) as low as –80 mV at I_C = –0.5 A / I_B = –5 mA, h_FE ≥ 250 at I_C = –0.5 A, and supports I_C = –5 A continuous collector current - used in LED drivers, CCFL backlighting, and relay driving circuits.

For engineers reviewing the 2STN2540 datasheet, 2STN2540 pinout, 2STN2540 application, or 2STN2540 equivalent, key selection criteria include its SOT-223 package thermal resistance (R_thj-amb = 78 °C/W), fast switching times (t_on = 75 ns, t_f = 62 ns), and low saturation voltage under high-current drive conditions.

Technical Context

This PNP transistor operates with V_CEO = –40 V and V_EBO = –6 V, enabling use in medium-power DC control paths where emitter-referenced switching is required. Its PB-HCD process yields high current gain stability across I_C = –0.5 A to –5 A while maintaining sub-150 mV V_CE(sat) up to –2 A.

The device is optimized for resistive-load switching with t_s = 426 ns storage time and t_f = 62 ns fall time at I_C = –1 A, V_CC = –10 V, and base drive of –0.1 A - critical for efficient LED/CCFL driver stage design and voltage regulation feedback loops.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	–40 V: Maximum safe collector-emitter blocking voltage in open-base configuration
I_C (cont.)	–5 A: Continuous collector current rating at T_amb = 25 °C, defining steady-state load drive capability
V_CE(sat)	–80 mV @ I_C = –0.5 A / I_B = –5 mA: Enables <100 mW conduction loss per switch in low-voltage logic-level driven stages
h_FE	250 min @ I_C = –0.5 A / V_CE = –2 V: Supports low-base-drive designs with minimal gate-driver overhead
t_f	62 ns @ I_C = –1 A: Limits switching transition losses in PWM-driven lighting and regulation circuits
R_thj-amb	78 °C/W on 1 cm² PCB copper: Determines thermal derating slope for ambient temperatures above 25 °C

Pinout & Package

SOT-223 package: 4-pin surface-mount outline with exposed collector tab (pin 3) for thermal dissipation; standard pin assignment confirmed per STMicroelectronics mechanical drawing 0046067_L.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitter terminal	Reference node for PNP current flow; connects to positive rail in high-side switch configurations
2 (Base)	Control input	Receives negative base current to turn on; requires current-limiting resistor in series with logic-level driver
3 (Collector)	Main current output	Exposed metal tab electrically connected to collector; must be thermally anchored to PCB copper for R_thj-amb compliance
4 (Emitter)	Second emitter connection	Internally tied to pin 1; provides redundant emitter path and improved solder joint reliability

Key Features

Feature	Design Value
PB-HCD fabrication process	Enables simultaneous high h_FE (>250) and ultra-low V_CE(sat) (<150 mV) across wide current range
Low thermal resistance package	R_thj-amb = 78 °C/W on 1 cm² PCB enables >1 W dissipation without heatsink in compact layouts
Fast switching performance	t_on/t_f ≤ 75/62 ns allows operation up to ~2 MHz in non-resonant PWM topologies
ECOPACK® lead-free construction	Complies with JEDEC JESD97 marking and RoHS requirements without compromising solderability or thermal performance

Applications

LED Driver Stage

CCFL Backlight Inverter

Use Scenario: Driving high-brightness white LEDs in emergency lighting systems requiring high efficiency and thermal robustness.

IC Role / Device Role / Timing Role: PNP power switch in constant-current sink configuration, controlled by microcontroller GPIO or dedicated LED driver IC.

Use Value: V_CE(sat) ≤ –120 mV at I_C = –1 A reduces conduction loss to <120 mW, improving system efficiency and easing thermal management.

Use Scenario: Switching stage in resonant half-bridge inverters for LCD panel CCFL backlights.

IC Role / Device Role / Timing Role: Low-loss, fast-turn-off PNP switch in high-frequency (20–100 kHz) resonant tank drive.

Use Value: t_f = 62 ns minimizes dead-time overlap losses; h_FE ≥ 150 at I_C = –2 A ensures stable base drive under varying load conditions.

Voltage Regulation Feedback

Electromechanical Relay Driver

Use Scenario: Active pass element in linear voltage regulators supplying sensitive analog circuitry.

IC Role / Device Role / Timing Role: Emitter-follower configured PNP transistor regulating output voltage via feedback loop error amplifier.

Use Value: Low V_CE(sat) and high h_FE enable tight load regulation (<1% deviation) with minimal dropout voltage and no external base current compensation.

Use Scenario: Direct-driving 12 V/24 V industrial relays from microcontroller outputs.

IC Role / Device Role / Timing Role: Medium-power PNP switch interfacing between logic-level MCU pins and relay coil (typically 50–200 mA).

Use Value: I_C = –5 A rating provides 10× safety margin over typical relay coil currents; fast t_on/t_f suppresses contact arcing during make/break transitions.

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_CE(sat) = –1.1 V @ I_C = –4 A (vs. –0.35 V for 2STN2540); h_FE = 20–70 (vs. 50–250)	Higher conduction loss limits use in high-efficiency LED/CCFL drivers; better suited for general-purpose relay or solenoid control	Select when cost sensitivity outweighs efficiency needs and base drive current is abundant
PN2907A	I_C = –600 mA max (vs. –5 A); R_thj-amb = 200 °C/W (vs. 78 °C/W); TO-92 package	Not suitable for >500 mA loads or surface-mount automated assembly; limited thermal capacity prevents sustained high-current operation	Only consider for low-power signal-level switching or prototyping where SOT-223 footprint is unavailable

Compared with MJD2955T4G and PN2907A, the 2STN2540 uniquely combines high current handling (–5 A), ultra-low saturation voltage (–80 mV), and fast switching (62 ns fall time) in an SMT-optimized SOT-223 package - making it the only option among the three viable for high-efficiency, high-frequency, medium-power PNP switching.

Availability

2STN2540 is available at Aetrix Electronics and suitable for LED driver design, CCFL backlighting, and relay control applications requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.

Supply support for 2STN2540 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, Switzerland, specializing in power management, analog, MEMS, and microcontroller technologies for industrial, automotive, and consumer markets.

The 2STN2540 belongs to ST's legacy power bipolar transistor family, engineered specifically for high-gain, low-saturation, fast-switching medium-power applications in lighting, power conversion, and electromechanical interface circuits.

FAQ

What is the maximum safe operating junction temperature for the 2STN2540?

The 2STN2540 has a maximum operating junction temperature (T_J) of 150 °C, as specified in Table 2 of the official ST datasheet (Rev 3, Jan 2008). This limit applies under all operating conditions, including pulsed and continuous modes. Exceeding this temperature risks permanent degradation of the PB-HCD structure and accelerated parameter drift.

Can the 2STN2540 be used in avalanche mode?

No - the 2STN2540 is not rated or characterized for avalanche operation. Its absolute maximum ratings specify only V_CEO = –40 V and V_CB0 = –40 V under open-emitter conditions. ST does not guarantee safe single-pulse or repetitive avalanche energy capability, and no SOA curves or avalanche test data are provided in the datasheet.

Is the SOT-223 pinout of the 2STN2540 compatible with standard SOT-223 footprints?

Yes - the 2STN2540 uses the standard SOT-223 mechanical outline defined in ST's drawing 0046067_L, with pin 1 (Emitter), pin 2 (Base), pin 3 (Collector/tab), and pin 4 (Emitter). Its dimensions (D = 6.5 mm typ, E = 3.5 mm typ, H = 7.0 mm typ) match JEDEC MO-178AB, ensuring compatibility with industry-standard SOT-223 land patterns and reflow profiles.

Does the 2STN2540 require a base resistor when driven by a 3.3 V microcontroller GPIO?

Yes - a series base resistor is mandatory. With V_BE(on) ≈ –1.25 V at I_C = –2 A, a 3.3 V GPIO sinking into the base requires ~2.05 V drop across the resistor. For reliable saturation at I_C = –2 A (requiring I_B ≥ –20 mA), a 100 Ω resistor limits base current to ~20.5 mA, satisfying h_FE ≥ 100 minimum requirement.

2STN2540 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Active

Transistor Type:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 450mV @ 500mA, 5A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 150 @ 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

2STN2540 FAQ

1.How can I place an order for 2STN2540 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2STN2540 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 2STN2540 reliable?

The price and inventory of 2STN2540 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2STN2540 is usually 5 days.

3.What payment methods are accepted for 2STN2540?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2STN2540 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2STN2540?

2STN2540 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2STN2540 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 2STN2540?

For technical support, including 2STN2540 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2STN2540 requirements.

6.How does Aetrix verify that 2STN2540 is sourced from the original manufacturer or authorized distributors?

All 2STN2540 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 2STN2540 meets industry standards.

7.What is the process for return or replacement of 2STN2540?

All 2STN2540 units undergo pre-shipment inspection (PSI). If there is an issue with 2STN2540, 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 2STN2540 part is unused and in its original packaging.

Return procedure for 2STN2540:

1.Submit a request within 90 days.

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

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