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

STMicroelectronics STF715

Name: STF715
Brand: STMicroelectronics
SKU: STF715
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STF715

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-243AA

Datasheet:: STF715.pdf

Description:: TRANS NPN 80V 1.5A SOT-89-3

Quantity:: RFQ Add To RFQ list

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Inventory:6,796

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Product details

Overview

STF715 from STMicroelectronics is an NPN medium-power bipolar junction transistor in SOT-223 package, rated for V_CEO = 80 V, I_C = 1.5 A, P_tot = 1.6 W at T_c = 25 °C, with h_FE ≥ 140 at I_C = 100 mA, used in voltage regulation and relay driver circuits.

For engineers reviewing the STF715 datasheet, STF715 pinout, STF715 application, or STF715 equivalent, key selection factors include its 80 V V_CEO, 1.5 A continuous collector current, SOT-223 thermal resistance (R_thj-amb = 78 °C/W on 1 cm² PCB), and saturation voltage of 0.25 V at 100 mA/10 mA drive.

Technical Context

The STF715 operates as a general-purpose switching transistor with planar silicon construction, optimized for medium-power linear and saturated-mode applications. Its rugged design supports sustained operation up to T_j = 150 °C and handles pulsed collector currents up to 2 A (t_p < 5 ms).

It exhibits low V_CE(sat) (0.25 V typical at I_C = 100 mA, I_B = 10 mA) and high DC current gain (h_FE = 140–40 across I_C = 100 mA to 1 A), enabling efficient base-driven switching in discrete power control stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 V - Maximum safe collector-emitter voltage under open-base condition; defines upper rail limit in switch-mode regulator or relay coil drive.
I_C	1.5 A - Continuous DC collector current rating; sets maximum load current capability in linear regulators or solenoid drivers.
P_tot	1.6 W - Total power dissipation at case temperature 25 °C; determines heatsinking requirement on standard PCB land pattern.
h_FE	140 (min @ I_C = 100 mA) - DC current gain; enables low-base-current drive for efficient transistor biasing in discrete amplifiers or switches.
V_CE(sat)	0.25 V (typ @ I_C = 100 mA, I_B = 10 mA) - Saturation voltage drop; directly impacts conduction loss and thermal rise in switching applications.
f_T	50 MHz - Transition frequency; indicates usable bandwidth for small-signal amplification or fast-switching control loops.

Pinout & Package

SOT-223 package with 4-pin configuration (3 active + 1 thermal tab); pin 1 = emitter, pin 2 = base, pin 3 = collector, pin 4 = collector (thermal tab connected internally to collector).

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Current return path; referenced to ground or negative rail in common-emitter configurations.
Pin 2	Base	Control input; requires ~10 mA drive for full saturation at 100 mA collector load.
Pins 3 & 4	Collector (dual connection)	Main power output node; pins 3 and 4 are electrically tied and thermally coupled to PCB copper for enhanced heat transfer.

Key Features

Feature	Design Value
Planar silicon process	Rugged construction ensures stable h_FE and breakdown performance over temperature and lifetime.
High V_CEO (80 V)	Supports direct interface with 24 V industrial control rails and 48 V telecom systems without external clamping.
Low V_CE(sat)	Reduces conduction loss below 250 mV at moderate loads, improving efficiency in linear pass elements and relay drivers.
Thermal resistance (78 °C/W)	Enables 1.6 W dissipation with ≤125 °C junction rise on minimal 1 cm² copper area-no external heatsink required.

Applications

Voltage Regulation

Relay Driver

Use Scenario: Linear voltage regulator pass element delivering 5–12 V at up to 1.2 A from unregulated 15–30 V input.

IC Role / Device Role / Timing Role: NPN series pass transistor controlling output voltage via base bias feedback loop.

Use Value: Low V_CE(sat) minimizes dropout and self-heating; h_FE ≥ 140 ensures stable regulation with simple op-amp error amplifier.

Use Scenario: Driving 24 VDC industrial relay coils (100–500 Ω) from microcontroller GPIO pins.

IC Role / Device Role / Timing Role: Discrete switch amplifying logic-level signals to deliver >100 mA coil current.

Use Value: 1.5 A I_C rating provides 5× safety margin; SOT-223 thermal mass sustains repeated actuation without derating.

Generic Switch

DC Motor Control (Low-Power)

Use Scenario: On/off control of LED arrays, solenoids, or small fans in embedded control panels.

IC Role / Device Role / Timing Role: Medium-power saturated switch replacing MOSFETs where gate drive complexity must be avoided.

Use Value: Base-driven simplicity eliminates need for level-shifting or gate drivers; V_CEO = 80 V accommodates back-EMF spikes.

Use Scenario: PWM-controlled bidirectional H-bridge half-bridge (with complementary PNP) for 12 V, <1 A brushed DC motors.

IC Role / Device Role / Timing Role: High-side or low-side switching element in discrete motor driver stage.

Use Value: f_T = 50 MHz supports clean PWM edge response up to ~500 kHz; rugged planar structure withstands inductive flyback stress.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD122G	V_CEO = 100 V, I_C = 3 A, P_tot = 2 W, SOT-223; higher voltage/current but larger die size.	Preferred in 48 V systems or where >1.5 A peak load is expected; slightly lower h_FE (60 min @ 1 A).	Select when higher V_CEO headroom or thermal margin is required; verify base drive compatibility due to higher I_B demand.
ZTX653	V_CEO = 60 V, I_C = 1 A, P_tot = 1 W, SOT-89; lower voltage rating and power, smaller footprint.	Suitable for 5–24 V consumer-grade switching; not recommended for 48 V or >1 A loads.	Choose for space-constrained designs with lower voltage rails; avoid in industrial relay or regulator use due to V_CEO and thermal limits.

Compared with MJD122G and ZTX653, the STF715 offers optimal balance of 80 V rating, 1.5 A capacity, and 1.6 W dissipation in SOT-223-making it ideal for 24–36 V industrial control where ZTX653 lacks voltage margin and MJD122G over-specifies.

Availability

STF715 is available at Aetrix Electronics and suitable for voltage regulation, relay driver, and generic switch applications requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging in tape-and-reel format.

Supply support for STF715 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 STF715 belongs to ST's legacy bipolar power transistor family, engineered specifically for robust, cost-effective discrete switching in industrial power supplies, control modules, and electromechanical interface circuits.

FAQ

What is the maximum junction temperature and how does it affect thermal design?

The STF715 has a maximum operating junction temperature of 150 °C. With R_thj-amb = 78 °C/W on a 1 cm² PCB copper area, it can dissipate 1.6 W at T_c = 25 °C. To maintain T_j ≤ 150 °C at ambient 70 °C, maximum allowable power drops to ~1.03 W-requiring either reduced load current or increased copper area.

Can STF715 replace STN715 in the same PCB footprint?

Yes-both STF715 (SOT-223) and STN715 (SOT-89) share identical electrical specifications but differ in package and thermal performance. STF715 offers lower R_thj-amb (78 vs. 89 °C/W) and higher P_tot (1.6 W vs. 1.4 W), making it a direct upgrade where board space allows SOT-223 mounting.

What base resistor value is recommended for switching a 24 V, 200 mA relay coil?

With h_FE ≥ 140 at I_C = 100 mA and V_BE(sat) ≈ 1.0 V, a 1 kΩ base resistor from a 5 V MCU GPIO yields I_B ≈ 4 mA-sufficient for ~560 mA I_C (well above 200 mA). For guaranteed saturation, use 470 Ω to deliver ~8.5 mA I_B.

Is STF715 suitable for linear amplifier applications?

Yes-its f_T = 50 MHz and h_FE stability across I_C make it viable for low-frequency audio preamplifiers or sensor signal conditioning. However, its V_CEO = 80 V and lack of matched pairs limit use in high-fidelity or differential stages; best suited for single-ended, low-gain, DC-coupled amplifiers.

STF715 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):: 1.5 A

Voltage - Collector Emitter Breakdown (Max):: 80 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 100mA, 1A

Current - Collector Cutoff (Max):: 1mA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 1A, 2V

Power - Max:: 1.4 W

Frequency - Transition:: 50MHz

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-89-3

STF715 FAQ

1.How can I place an order for STF715 through Aetrix?

Please submit a Request for Quotation (RFQ) for STF715 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 STF715 reliable?

The price and inventory of STF715 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STF715 is usually 5 days.

3.What payment methods are accepted for STF715?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STF715 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STF715?

STF715 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STF715 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 STF715?

For technical support, including STF715 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STF715 requirements.

6.How does Aetrix verify that STF715 is sourced from the original manufacturer or authorized distributors?

All STF715 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 STF715 meets industry standards.

7.What is the process for return or replacement of STF715?

All STF715 units undergo pre-shipment inspection (PSI). If there is an issue with STF715, 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 STF715 part is unused and in its original packaging.

Return procedure for STF715:

1.Submit a request within 90 days.

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

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