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

STMicroelectronics 2STF2340

Name: 2STF2340
Brand: STMicroelectronics
SKU: 2STF2340
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2STF2340

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-243AA

Datasheet:: 2STF2340.pdf

Description:: TRANS PNP 40V 3A SOT-89-3

Quantity:: RFQ Add To RFQ list

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Inventory:9,214

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Product details

Overview

2STF2340 from STMicroelectronics is a PNP bipolar junction transistor (BJT) optimized for low-voltage, fast-switching power applications. It features V_CE(sat) = –250 mV at I_C = –2 A / I_B = –100 mA, h_FE = 100–450 (I_C = –0.1 to –3 A), f_T = 100 MHz, and is housed in an SOT-89 package rated for 1.4 W at T_amb = 25 °C. It is used in LED drivers and DC-DC converter output stages.

For engineers reviewing the 2STF2340 datasheet, 2STF2340 pinout, 2STF2340 application, or 2STF2340 equivalent, key selection criteria include saturation voltage under high current, DC gain linearity across operating range, thermal resistance (R_thJA = 89 °C/W), switching speed (t_on = 80 ns, t_off = 450 ns), and SOT-89 mechanical compatibility with PCB layout constraints.

Technical Context

This PNP transistor employs ST's PB-HDC (Power Bipolar High Density Current) process, enabling simultaneous high current gain and low V_CE(sat). Its breakdown ratings-V_CES = –40 V, V_EBO = –5 V-and robust I_CM = –6 A (5 ms pulse) support reliable operation in transient-loaded power switches.

The device operates up to T_J = 150 °C with R_thJA = 89 °C/W on 1 cm² PCB copper, and exhibits C_CBO = 50 pF at V_CB = –10 V, supporting stable high-frequency switching in non-inductive resistive-load configurations per Figure 11 test circuit.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CE(sat)	–250 mV @ I_C = –2 A, I_B = –100 mA - enables <150 mW conduction loss in 2 A load paths
h_FE	100–450 @ I_C = –0.1 to –3 A - supports wide base drive margin without overdesign
f_T	100 MHz @ I_C = –0.1 A - ensures stable gain in sub-10 MHz switching control loops
t_on/t_off	80 ns / 450 ns @ I_C = –1.5 A - defines minimum PWM period for ≤1 MHz DC-DC operation
R_thJA	89 °C/W - requires ≥1 cm² copper pad for safe 1.4 W continuous dissipation at 25 °C ambient
V_CES	–40 V - sets maximum allowable supply rail for LED backlight or buck converter output stage
C_CBO	50 pF @ V_CB = –10 V - limits Miller-induced gate drive coupling in emitter-follower configurations

Pinout & Package

SOT-89 package: 3-terminal surface-mount plastic package with exposed collector tab for thermal relief; pin 1 = Emitter, pin 2 = Base, pin 3 = Collector (tab). Mounting requires solderable copper area ≥1 cm² per thermal data.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Current sink node; connected to system ground or low-side return path in PNP switch configuration
Pin 2	Base	Control input; driven negative relative to emitter to turn on; requires ~100 mA for full saturation at 2 A
Pin 3	Collector	High-current output node; electrically and thermally tied to exposed metal tab; must be routed to power rail

Key Features

Feature	Design Value
Very low V_CE(sat)	–250 mV at 2 A enables >98% efficiency in 5 V/2 A LED driver output stage
High h_FE linearity	h_FE ≥ 180 at 1 A ensures stable base drive design without active current limiting
Fast switching	80 ns t_on supports PWM dimming up to 10 MHz in display backlight circuits
PB-HDC process	Enables concurrent optimization of gain and saturation voltage-unachievable in standard BJT processes

Applications

LED Backlight Driver

Hard Disk Drive Power Switch

Use Scenario: Constant-current switching for white LED strings in notebook displays.

IC Role / Device Role / Timing Role: PNP high-side switch controlling LED cathode current path with PWM modulation.

Use Value: Low V_CE(sat) minimizes heat in space-constrained display bezels; fast t_off prevents ghosting during high-frequency dimming.

Use Scenario: 5 V rail enable/disable for HDD spindle motor and actuator ICs.

IC Role / Device Role / Timing Role: Low-loss power OR-ing and sequencing switch in motherboard VRM output stage.

Use Value: 1.4 W rating and 89 °C/W thermal resistance allow direct mounting without heatsink; high h_FE reduces base drive burden on PMIC GPIO.

Mobile Phone DC-DC Converter

USB-C Power Delivery Load Switch

Use Scenario: Synchronous rectifier replacement in 3.3 V buck converter for AP core supply.

IC Role / Device Role / Timing Role: PNP pass transistor in linear post-regulator or low-noise LDO bypass path.

Use Value: 100 MHz f_T ensures stability with ceramic output caps; low C_CBO avoids noise coupling into sensitive RF sections.

Use Scenario: Inrush-limited 5 V load switch for USB-C peripheral port power management.

IC Role / Device Role / Timing Role: Controlled high-side switch with soft-start via base RC network.

Use Value: –40 V V_CES headroom accommodates USB-C transient surges; –6 A I_CM supports hot-plug peak currents.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2STN2340	SOT-223 package; R_thJA = 78 °C/W; P_TOT = 1.6 W; same electrical specs	Better thermal performance in higher-power or less ventilated layouts	Select when board space allows larger footprint and >1.4 W continuous dissipation is required
MJD2955T4G	TO-220AB package; V_CE(sat) = –1.2 V @ I_C = –4 A; h_FE = 20–70; slower switching	Higher current capacity but significantly higher conduction loss and lower gain	Choose only if mechanical mounting or legacy TO-220 footprint is mandatory and efficiency is secondary

Compared with 2STN2340, the 2STF2340 trades 0.2 W power handling and 11 °C/W thermal resistance for 30% smaller PCB area; versus MJD2955T4G, it delivers 4× lower V_CE(sat) and 6× higher h_FE, enabling simpler base drive and cooler operation at 2 A.

Availability

2STF2340 is available at Aetrix Electronics and suitable for LED backlight drivers, motherboard power sequencing, and mobile DC-DC converters requiring stable component supply, consistent parametric performance, and long-term industrial availability.

Supply support for 2STF2340 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The 2STF2340 belongs to ST's "Low Voltage Power Transistors" product line, engineered specifically for high-efficiency, compact-area switching in battery-powered and space-constrained systems.

FAQ

Is the 2STF2340 RoHS-compliant and halogen-free?

Yes. The 2STF2340 is manufactured in ST's ECOPACK®-compliant SOT-89 package, meeting RoHS Directive 2011/65/EU and JEDEC JS709A halogen-free requirements. Full compliance documentation is available in ST's ECOPACK® database at www.st.com.

Can the 2STF2340 replace an NPN transistor in a circuit?

No-it is a PNP device and cannot function as a direct NPN replacement without inverting biasing and signal polarity. Circuit redesign is required to accommodate its complementary switching behavior, including reversed base drive polarity and emitter-high topology.

What is the recommended PCB layout for thermal management?

Use ≥1 cm² of 2 oz copper connected directly to the collector (pin 3/tab) with ≥4 thermal vias (0.3 mm diameter) to inner ground plane. Avoid placing components or traces near the tab area. Refer to Figure 3 derating curve for ambient temperature derating above 25 °C.

Does the 2STF2340 have built-in ESD protection?

No. The device has no integrated ESD protection diodes. External TVS or series resistance must be added on base and emitter lines in handheld or connector-exposed applications per IEC 61000-4-2 Level 2 (4 kV contact).

2STF2340 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-243AA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 3 A

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

Vce Saturation (Max) @ Ib, Ic:: 350mV @ 150mA, 3A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 180 @ 1A, 2V

Power - Max:: 1.4 W

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-89-3

2STF2340 FAQ

1.How can I place an order for 2STF2340 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2STF2340 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 2STF2340 reliable?

The price and inventory of 2STF2340 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2STF2340 is usually 5 days.

3.What payment methods are accepted for 2STF2340?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2STF2340 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2STF2340?

2STF2340 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2STF2340 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 2STF2340?

For technical support, including 2STF2340 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2STF2340 requirements.

6.How does Aetrix verify that 2STF2340 is sourced from the original manufacturer or authorized distributors?

All 2STF2340 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 2STF2340 meets industry standards.

7.What is the process for return or replacement of 2STF2340?

All 2STF2340 units undergo pre-shipment inspection (PSI). If there is an issue with 2STF2340, 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 2STF2340 part is unused and in its original packaging.

Return procedure for 2STF2340:

1.Submit a request within 90 days.

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

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