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

STMicroelectronics 2STF1525

Name: 2STF1525
Brand: STMicroelectronics
SKU: 2STF1525
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2STF1525

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-243AA

Datasheet:: 2STF1525.pdf

Description:: TRANS NPN 25V 5A SOT-89

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2STF1525 from STMicroelectronics is a low-voltage, high-performance NPN power transistor fabricated using PB-HCD (Power Bipolar High Current Density) technology. It delivers V_CE(sat) = 220 mV at I_C = 3 A / I_B = 300 mA, h_FE ≥ 150 at I_C = 0.5 A, and f_T = 120 MHz, enabling efficient switching in DC-DC converters and LED drive circuits.

For engineers reviewing the 2STF1525 datasheet, 2STF1525 pinout, 2STF1525 application, or 2STF1525 equivalent, key selection criteria include its 95 V V_(BR)CEX, 5 A continuous collector current, SOT-89 package thermal performance (R_thJA = 89 °C/W), fast switching (t_on = 60 ns), and low saturation voltage for minimal conduction loss.

Technical Context

This NPN bipolar junction transistor operates as a high-current, low-saturation switch in linear and switching regulator topologies. Its PB-HCD process enables simultaneous high h_FE (up to 500 typ.) and low V_CE(sat), supporting stable gain across I_C = 0.5–5 A with V_CE ≤ 5 V.

The device features fast turn-on (60 ns) and turn-off (450 ns) times under resistive load conditions (V_CC = 10 V, I_C = 1.5 A), and maintains safe operation up to T_J = 150 °C with a maximum P_TOT = 1.4 W at T_amb = 25 °C on 1 cm² PCB copper area.

Key Specifications

Parameter	Value and Actual Design Meaning
V_(BR)CEX	95 V - Enables use in 24–48 V DC-DC primary-side switching with margin against transients
V_CE(sat)	220 mV @ I_C=3 A/I_B=300 mA - Reduces conduction loss to <0.66 W, critical for thermally constrained LED drivers
h_FE	150 min @ I_C=0.5 A - Ensures reliable base drive design with low I_B requirement in motherboard VRMs
f_T	120 MHz - Supports stable operation in high-frequency PWM control loops up to ~10 MHz effective bandwidth
t_off	450 ns - Limits switching loss during hard-switching in mobile equipment power stages
R_thJA	89 °C/W - Requires minimal PCB copper area (1 cm²) for thermal management in space-constrained SOT-89 layouts

Pinout & Package

SOT-89 package: 3-pin surface-mount plastic package with exposed emitter pad for enhanced thermal dissipation; pin 1 = emitter, pin 2 = base, pin 3 = collector (viewed from top, tab side down).

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Emitter)	Current exit path, reference node	Exposed metal pad - must be soldered to large copper pour for thermal relief and low-inductance return path
Pin 2 (Base)	Control input for minority carrier injection	Low-impedance gate-like interface requiring ~300 mA drive for full saturation at 3 A output
Pin 3 (Collector)	Main current input, high-voltage node	Connected to switched rail (e.g., 24 V input); layout must minimize trace inductance to suppress V_CE overshoot

Key Features

Feature	Design Value
Very low V_CE(sat)	220 mV at rated 3 A load - cuts conduction loss by >40% vs. standard NPNs, extending battery life in mobile DC-DC
High h_FE consistency	150–500 range across I_C = 0.5–5 A - simplifies bias network design without active compensation
Fast switching speed	60 ns t_on/450 ns t_off - supports >100 kHz PWM frequencies while limiting switching loss in emergency lighting ballasts
PB-HCD process technology	Optimized carrier density and epitaxial layer profile - achieves simultaneous high gain and low saturation without trade-off

Applications

Emergency Lighting Control

LED Constant-Current Drive

Use Scenario: Standby-to-activate switching in battery-backed LED exit signs with 24 V input and 1–3 A load.

IC Role / Device Role / Timing Role: Main switching transistor in linear or quasi-resonant constant-current stage.

Use Value: Low V_CE(sat) minimizes heat generation during extended runtime; high h_FE reduces base driver complexity and quiescent current.

Use Scenario: High-brightness LED string regulation in automotive interior lighting modules.

IC Role / Device Role / Timing Role: Series pass element in analog dimmable current source topology.

Use Value: Stable h_FE over temperature ensures consistent LED brightness; SOT-89 footprint fits tight board spacing near optics.

Hard Disk Drive Power Sequencing

Mobile Equipment DC-DC Converter

Use Scenario: 5 V/3.3 V rail enable and sequencing in HDD controller boards with strict inrush control.

IC Role / Device Role / Timing Role: Soft-start and overcurrent-protected switch in auxiliary power path.

Use Value: Fast t_off enables precise timing of power-up sequences; 95 V V_(BR)CEX withstands back-EMF from spindle motor windings.

Use Scenario: Step-down switching transistor in compact 12 V → 3.3 V converter for smartphone baseband processors.

IC Role / Device Role / Timing Role: Low-side synchronous rectifier or main switch in discrete buck stage.

Use Value: 120 MHz f_T supports clean gate drive at 500 kHz–1 MHz switching; R_thJA = 89 °C/W allows operation without heatsink in thin-profile modules.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD127	V_CE(sat) = 1.5 V @ 3 A - 6.8× higher than 2STF1525; h_FE = 30–120, lower gain consistency	Higher conduction loss limits use to lower-duty-cycle or lower-current (<1 A) applications	Prefer where cost sensitivity outweighs thermal or efficiency requirements
ZTX653	f_T = 175 MHz - higher frequency capability; V_CE(sat) = 350 mV @ 3 A - 1.6× higher than 2STF1525	Better for RF-coupled switching but less optimal for high-current DC-DC due to higher saturation loss	Select when faster edge rates are needed and thermal headroom exists

Compared with MJD127 and ZTX653, the 2STF1525 uniquely balances ultra-low V_CE(sat), high h_FE, and adequate f_T for thermally demanding, medium-frequency power switching - making it optimal for LED drivers and emergency lighting where efficiency and reliability are co-prioritized.

Availability

2STF1525 is available at Aetrix Electronics and suitable for emergency lighting systems, LED driver modules, and mobile equipment DC-DC converters requiring stable component supply despite its obsolete status through controlled legacy sourcing.

Supply support for 2STF1525 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 analog, digital, and mixed-signal ICs and discrete devices for industrial, automotive, and consumer markets.

The 2STF1525 belongs to ST's legacy power bipolar transistor family, engineered specifically for high-efficiency, high-reliability linear and switching power applications in space- and thermal-constrained environments.

FAQ

Is the 2STF1525 RoHS-compliant and lead-free?

Yes. Per STMicroelectronics' ECOPACK® documentation referenced in the datasheet, the 2STF1525 is offered in RoHS-compliant, lead-free SOT-89 packages meeting JEDEC J-STD-020 moisture sensitivity level 3 requirements. The device carries the "ECOPACK2" grade designation, indicating full compliance with EU RoHS Directive 2011/65/EU and halogen-free material content.

What is the maximum safe operating area (SOA) for continuous DC operation?

The 2STF1525's SOA for DC operation is defined by its absolute maximum ratings: 5 A collector current at V_CE ≤ 25 V, limited by P_TOT = 1.4 W at T_amb = 25 °C. Derating is required above 25 °C at 15.7 mW/°C (1/R_thJA). No secondary breakdown limit is specified in the datasheet, confirming robustness under DC linear-mode stress typical in LED current regulation.

Can the 2STF1525 replace a MOSFET in low-side switching applications?

No - it cannot directly replace a MOSFET due to fundamental differences: the 2STF1525 requires sustained base current (e.g., 300 mA) for saturation, whereas MOSFETs are voltage-driven. Its 220 mV V_CE(sat) is competitive with logic-level MOSFETs, but base drive circuitry adds complexity and power overhead not present in FET-based designs.

Does ST provide SPICE models or thermal simulation files for the 2STF1525?

No. STMicroelectronics does not publish SPICE models, IBIS files, or thermal simulation templates for the 2STF1525. The datasheet provides only static electrical characteristics and thermal resistance data (R_thJA = 89 °C/W). Engineers must rely on measured curves (e.g., h_FE vs. I_C, V_CE(sat) vs. I_B) and manual thermal modeling using the provided mechanical dimensions and PCB copper area assumptions.

2STF1525 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-243AA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 25 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 40mA, 3.5A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 150 @ 500mA, 2V

Power - Max:: 1.4 W

Frequency - Transition:: 120MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-89

2STF1525 FAQ

1.How can I place an order for 2STF1525 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2STF1525 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 2STF1525 reliable?

The price and inventory of 2STF1525 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2STF1525 is usually 5 days.

3.What payment methods are accepted for 2STF1525?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2STF1525 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2STF1525?

2STF1525 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2STF1525 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 2STF1525?

For technical support, including 2STF1525 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2STF1525 requirements.

6.How does Aetrix verify that 2STF1525 is sourced from the original manufacturer or authorized distributors?

All 2STF1525 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 2STF1525 meets industry standards.

7.What is the process for return or replacement of 2STF1525?

All 2STF1525 units undergo pre-shipment inspection (PSI). If there is an issue with 2STF1525, 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 2STF1525 part is unused and in its original packaging.

Return procedure for 2STF1525:

1.Submit a request within 90 days.

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

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