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

STMicroelectronics STX715

Name: STX715
Brand: STMicroelectronics
SKU: STX715
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STX715

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: STX715.pdf

Description:: TRANS NPN 80V 1.5A TO-92-3

Quantity:: RFQ Add To RFQ list

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Inventory:5,271

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Product details

Overview

STX715 from STMicroelectronics is an NPN bipolar junction transistor (BJT) designed for low-voltage switching and linear regulation, housed in a TO-92 plastic package. It supports 80 V V_CEO, 1.5 A continuous collector current, and delivers 0.9 W power dissipation at 25 °C ambient - used in relay drivers, voltage regulators, and generic on/off control circuits.

For engineers reviewing the STX715 datasheet, STX715 pinout, STX715 application, or STX715 equivalent, key selection criteria include V_CEO = 80 V, I_C = 1.5 A, h_FE ≥ 40 @ 1 A, V_CE(sat) ≤ 0.5 V @ 1 A/100 mA, and TO-92 mechanical compatibility for through-hole assembly.

Technical Context

The STX715 operates as a general-purpose NPN BJT with planar epitaxial construction, optimized for ruggedness in low-voltage (<80 V) switching applications. Its 150 °C maximum junction temperature and 140 °C/W thermal resistance enable reliable operation under moderate power dissipation without forced cooling.

It exhibits DC current gain h_FE of 140 (min) at 100 µA, 80 (min) at 500 mA, and 40 (min) at 1 A - supporting both small-signal amplification and high-current saturation switching. Transition frequency f_T is 50 MHz at 100 mA/10 V, confirming suitability for audio-frequency and low-speed digital switching.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 V - maximum safe collector-emitter voltage with base open; defines upper limit for switch blocking capability.
I_C	1.5 A - continuous DC collector current rating; determines max load drive capacity in relay or regulator stages.
V_CE(sat)	0.5 V @ 1 A/100 mA - low saturation voltage ensures minimal conduction loss and heat generation in switching mode.
h_FE	40 min @ 1 A - verified DC current gain at full rated current; enables predictable base drive sizing for saturated switching.
f_T	50 MHz - transition frequency confirms usable bandwidth up to audio range; not suitable for RF or high-speed logic.
P_TOT	0.9 W @ T_amb = 25 °C - total power dissipation limit; requires derating above 25 °C per R_thJA = 140 °C/W.
T_J(max)	150 °C - maximum junction temperature; sets thermal design margin for PCB layout and ambient conditions.

Pinout & Package

STX715 is supplied in the standard TO-92 plastic package (JEDEC TO-92 variant), with three leads arranged in linear configuration: Emitter (left), Base (center), Collector (right) when viewing the flat side with leads downward.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	Reference node for biasing; connects to ground or low-side return path in common-emitter configurations.
Base (B)	Control input	Receives current-limited drive signal to turn on/off transistor; requires ~100 mA peak for full saturation at 1 A load.
Collector (C)	Current source terminal	Connects to load and supply rail; carries full switched current; must withstand 80 V transient during turn-off.

Key Features

Feature	Design Value
High ruggedness	Rated for 2 A peak collector current (5 ms pulse) and 140 V V_CBO, enabling tolerance to inductive kickback in relay loads.
Low V_CE(sat)	0.25 V typical @ 100 mA/10 mA ensures <25 mW conduction loss in small-signal switching applications.
TO-92 through-hole compatibility	Standard lead spacing (2.41–2.67 mm e, 12.7–15.49 mm L) ensures plug-and-play replacement in legacy designs.
ECOPACK® compliant	Meets RoHS and halogen-free requirements per ST's environmental packaging standards for industrial use.

Applications

Voltage Regulation

Relay Driver

Use Scenario: Linear voltage regulator pass element in 5–12 V output supplies with adjustable feedback.

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

Use Value: Low V_CE(sat) minimizes dropout voltage; 80 V V_CEO supports input up to 72 V DC in industrial SMPS pre-regulators.

Use Scenario: Driving 12 V or 24 V electromagnetic relays in PLC I/O modules and HVAC controllers.

IC Role / Device Role / Timing Role: High-current switch interfacing microcontroller GPIO to relay coil.

Use Value: 1.5 A I_C handles typical 100–500 mA relay coils with margin; ruggedness absorbs back-EMF spikes without snubber.

Generic Switch

DC Motor Control (Low Power)

Use Scenario: On/off control of LED banks, solenoids, or small fans in consumer appliances.

IC Role / Device Role / Timing Role: Single-pole, single-throw (SPST) solid-state switch replacing mechanical contacts.

Use Value: TO-92 footprint allows compact board layout; 0.9 W dissipation supports continuous duty at ≤500 mA load current.

Use Scenario: Direction-agnostic PWM speed control of brushed DC motors ≤10 W in battery-powered tools.

IC Role / Device Role / Timing Role: Low-side switch in half-H-bridge or single-ended motor driver stage.

Use Value: 50 MHz f_T supports PWM frequencies up to 20 kHz without switching loss penalty; h_FE stability ensures consistent gate/base drive.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC337-40	V_CEO = 45 V, I_C = 0.8 A, h_FE = 250–630 - lower voltage/current rating, higher gain.	Limited to ≤40 V systems; unsuitable for 72 V input regulators or high-power relay coils.	Prefer where gain consistency and low base drive are critical, and voltage/current demands are modest.
MJD122	V_CEO = 100 V, I_C = 3 A, TO-220 package - higher power, surface-mount incompatible.	Requires heatsink for >1 A continuous; not drop-in replaceable due to footprint and thermal interface.	Choose for higher current or voltage headroom where board space and thermal management allow TO-220 mounting.

Compared with BC337-40 and MJD122, the STX715 uniquely balances 80 V blocking, 1.5 A current, TO-92 fit, and ruggedness - making it optimal for cost-sensitive, medium-power through-hole switching where thermal constraints preclude larger packages and voltage exceeds 45 V.

Availability

STX715 is available at Aetrix Electronics and suitable for voltage regulation, relay driving, and generic switching applications requiring stable component supply across industrial control, appliance manufacturing, and embedded power subsystems.

Supply support for STX715 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The STX715 belongs to ST's general-purpose bipolar transistor product line, engineered for reliability and manufacturability in cost-sensitive, through-hole assembled power interface circuits.

FAQ

What is the maximum safe operating voltage for STX715 in a relay driver circuit?

The STX715 has a V_CEO rating of 80 V, meaning it can safely block up to 80 V between collector and emitter with base open. In relay driver applications, this allows direct use with 24 V or 48 V DC coils, provided flyback protection limits transient voltage to ≤80 V during turn-off. Exceeding this risks avalanche breakdown and permanent damage.

Can STX715 be used in linear amplifier configurations?

Yes - its h_FE of 140 (min) at 100 µA and 40 (min) at 1 A, along with f_T = 50 MHz, supports low-frequency linear amplification (e.g., audio preamps or sensor signal conditioning). However, its 0.9 W power limit and thermal resistance require careful biasing and heatsinking to avoid thermal runaway at higher quiescent currents.

Is STX715 RoHS-compliant and lead-free?

Yes - STX715 is manufactured in ECOPACK®-compliant versions meeting RoHS Directive 2011/65/EU and is halogen-free. The "ECOPACK®" marking on packaging and documentation confirms compliance; no leaded variants are offered in current production.

How does STX715 compare to PN2222A in terms of switching performance?

STX715 offers higher V_CEO (80 V vs. 40 V), higher I_C (1.5 A vs. 0.8 A), and lower V_CE(sat) (0.5 V vs. 0.6–1.0 V @ 1 A), making it superior for higher-voltage, higher-current switching. However, PN2222A has broader h_FE distribution and wider legacy design adoption in low-power signal stages.

STX715 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Packaging:: Bulk

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:: 900 mW

Frequency - Transition:: 50MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

STX715 FAQ

1.How can I place an order for STX715 through Aetrix?

Please submit a Request for Quotation (RFQ) for STX715 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 STX715 reliable?

The price and inventory of STX715 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STX715 is usually 5 days.

3.What payment methods are accepted for STX715?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STX715 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STX715?

STX715 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STX715 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 STX715?

For technical support, including STX715 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STX715 requirements.

6.How does Aetrix verify that STX715 is sourced from the original manufacturer or authorized distributors?

All STX715 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 STX715 meets industry standards.

7.What is the process for return or replacement of STX715?

All STX715 units undergo pre-shipment inspection (PSI). If there is an issue with STX715, 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 STX715 part is unused and in its original packaging.

Return procedure for STX715:

1.Submit a request within 90 days.

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

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