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

STMicroelectronics 2STF2550

Name: 2STF2550
Brand: STMicroelectronics
SKU: 2STF2550
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2STF2550

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-243AA

Datasheet:: 2STF2550.pdf

Description:: TRANS PNP 50V 5A SOT-89-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2STF2550 from STMicroelectronics is a low-voltage, fast-switching PNP power bipolar transistor fabricated using PB-HCD (Power Bipolar High Current Density) technology. It delivers V_CE(sat) = −0.39 V (typ.) at I_C = −3 A / I_B = −300 mA, h_FE = 350 (min.) at I_C = −0.5 A, and operates up to T_J = 150 °C - enabling high-efficiency current control in compact LED driver and battery charging circuits.

For engineers reviewing the 2STF2550 datasheet, 2STF2550 pinout, 2STF2550 application, or 2STF2550 equivalent, this device is selected for designs requiring low-saturation PNP switching with stable DC gain across 0.5–5 A load range, thermal robustness on minimal PCB copper, and SOT-89-compatible footprint constraints.

Technical Context

This PNP transistor uses ST's PB-HCD process to simultaneously optimize current gain and saturation voltage - achieving h_FE ≥ 350 at low collector current while maintaining V_CE(sat) ≤ −0.55 V under 3 A conduction. Its −50 V V_CEO rating supports operation in 24 V and 36 V rail systems with margin.

Thermal design is enabled by R_thJA = 89 °C/W on 1 cm² PCB copper, and fast switching (t_on = 80 ns, t_off = 300 ns) allows use in PWM-based regulation above 100 kHz without significant switching loss penalties.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−50 V: Supports 24 V/36 V supply rails with 100 % safety margin against transients.
I_C (cont.)	−5 A: Enables direct drive of medium-power LED strings or battery charge paths without external current amplification.
V_CE(sat)	−0.39 V (typ.): Reduces conduction loss to <1.2 W at 3 A, minimizing heatsink requirements.
h_FE	350 (min. @ I_C = −0.5 A): Ensures reliable base drive with low-current controllers (e.g., MCU GPIO).
t_off	300 ns: Allows stable PWM operation up to ~300 kHz before switching losses dominate.
R_thJA	89 °C/W: Achieves 150 °C junction temperature with only 1 cm² copper pad at 1.4 W dissipation.

Pinout & Package

SOT-89 package: 3-pin surface-mount plastic case with exposed emitter tab (pins 2 and 4 internally connected to collector, pin 3 to emitter, pin 1 to base). Mounting requires thermal pad soldering to PCB copper for rated power dissipation.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (B)	Base	Low-impedance control input; requires −300 mA base drive for full 3 A collector conduction.
Pins 2 & 4 (C)	Collector	Internally shorted terminals; primary current path into device; thermally coupled to package backside.
Pin 3 (E)	Emitter	Common reference node; connects to system ground or negative rail; carries full load current.

Key Features

Feature	Design Value
Very low V_CE(sat)	−0.39 V typ. at −3 A enables >95 % efficiency in linear-regulated battery chargers.
High h_FE at mid-current	110–350 range across −0.5 A to −3 A ensures predictable base drive sizing without overdesign.
Fast switching	80 ns t_on/300 ns t_off supports high-frequency PWM dimming and synchronous rectifier timing.
Robust thermal rating	T_J(max) = 150 °C with R_thJA = 89 °C/W allows operation in sealed enclosures up to 70 °C ambient.

Applications

LED Driver Circuits

Battery Charging Control

Use Scenario: Constant-current driving of multi-segment white LED arrays in portable lighting.

IC Role / Device Role / Timing Role: PNP switch regulating current through LED string via emitter-follower configuration.

Use Value: Low V_CE(sat) minimizes voltage headroom loss, extending runtime on single-cell Li-ion supplies.

Use Scenario: Linear current-limiting stage in USB-C PD-compliant 5–20 V battery charger IC reference designs.

IC Role / Device Role / Timing Role: Pass element controlling charge current into Li-ion/LiPo cells during CC phase.

Use Value: Stable h_FE ensures accurate current mirroring with low-base-drive overhead from op-amp feedback loop.

Mobile Equipment Power Path

Voltage Regulation Modules

Use Scenario: Reverse-polarity protection and load switching in smartphone accessory docks and power banks.

IC Role / Device Role / Timing Role: High-side PNP switch enabling/disabling 5 V/9 V/12 V output rails.

Use Value: Fast t_off prevents shoot-through during rail sequencing; low leakage (ICBO < −0.1 µA) preserves standby battery life.

Use Scenario: Adjustable negative LDO output stage in industrial sensor signal conditioning modules.

IC Role / Device Role / Timing Role: Series pass transistor delivering −3.3 V to −12 V at up to 5 A with external feedback.

Use Value: −50 V V_CEO accommodates wide input ranges; high h_FE reduces dropout voltage sensitivity to base drive variation.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MBT3906DW1T1G	Smaller SOT-363 package; I_C = −200 mA; V_CE(sat) = −0.4 V @ −50 mA - not rated for >1 A continuous.	Only suitable for signal-level logic inversion or bias networks, not power switching.	Select only for low-current biasing where footprint is critical and thermal load is negligible.
PN2907A	TO-92 package; I_C = −600 mA; V_CE(sat) = −1.6 V @ −500 mA - 4× higher conduction loss than 2STF2550 at same current.	Limited to <1 W dissipation; unsuitable for battery charger or LED driver thermal profiles.	Choose only for prototyping or low-power legacy replacements where SOT-89 assembly is unavailable.

Compared with MBT3906DW1T1G and PN2907A, the 2STF2550 uniquely combines 5 A capability, sub-0.5 V saturation, and SOT-89 thermal performance - making it the only viable option for production-grade medium-power PNP switching where board space and thermal budget are constrained.

Availability

2STF2550 is available at Aetrix Electronics and suitable for LED driver circuits, battery charging control, and mobile equipment power path management requiring stable component supply, consistent parametric binning, and long-term manufacturing continuity.

Supply support for 2STF2550 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, designing and manufacturing microcontrollers, power transistors, sensors, and analog ICs for industrial, automotive, and consumer markets.

The 2STF2550 belongs to ST's PB-HCD bipolar power transistor family, engineered specifically for high-current, low-loss linear and switching applications in space-constrained portable and battery-powered systems.

FAQ

What is the maximum safe continuous collector current for 2STF2550?

The absolute maximum continuous collector current is −5 A at T_A = 25 °C with adequate PCB copper area (1 cm²). Derating is required above 25 °C ambient: at 70 °C ambient, max I_C drops to approximately −3.2 A due to thermal limits (R_thJA = 89 °C/W, T_J(max) = 150 °C).

Can 2STF2550 be used in avalanche mode?

No - the 2STF2550 is not rated or characterized for avalanche energy handling. Its absolute maximum ratings specify only V_CEO = −50 V under non-avalanche conditions (I_B = 0 A), and no EAS or SOA curves are provided in DS5965. Use clamping diodes or snubbers for inductive load switching.

Is the SOT-89 package lead-free and RoHS compliant?

Yes - the 2STF2550 is offered in ECOPACK2-compliant SOT-89 packaging, meeting RoHS Directive 2011/65/EU and REACH SVHC requirements. The "ECOPACK" marking on the device top indicates compliance, and full material declarations are available via ST's product webpage.

How does base-emitter saturation voltage affect drive circuit design?

V_BE(sat) = −1.0 to −1.2 V (typ./max) at −3 A collector current means the base driver must sink ≥300 mA while sustaining ≥1.2 V reverse drop. This requires either a dedicated low-impedance gate driver or an NPN pre-driver stage - standard MCU GPIO cannot directly drive it at full current.

2STF2550 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-243AA

Packaging:: Tape & Reel (TR)

Product Status:: Active

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:: 1.4 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-89-3

2STF2550 FAQ

1.How can I place an order for 2STF2550 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2STF2550 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 2STF2550 reliable?

The price and inventory of 2STF2550 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2STF2550 is usually 5 days.

3.What payment methods are accepted for 2STF2550?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2STF2550 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2STF2550?

2STF2550 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2STF2550 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 2STF2550?

For technical support, including 2STF2550 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2STF2550 requirements.

6.How does Aetrix verify that 2STF2550 is sourced from the original manufacturer or authorized distributors?

All 2STF2550 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 2STF2550 meets industry standards.

7.What is the process for return or replacement of 2STF2550?

All 2STF2550 units undergo pre-shipment inspection (PSI). If there is an issue with 2STF2550, 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 2STF2550 part is unused and in its original packaging.

Return procedure for 2STF2550:

1.Submit a request within 90 days.

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

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