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

STMicroelectronics STN724

Name: STN724
Brand: STMicroelectronics
SKU: STN724
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STN724

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-261-4, TO-261AA

Datasheet:: STN724.pdf

Description:: TRANS NPN 30V 3A SOT-223

Quantity:: RFQ Add To RFQ list

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Inventory:7,564

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Product details

Overview

STN724 from STMicroelectronics is an NPN medium-power bipolar junction transistor in SOT-223 package, rated for 30 V V_CEO, 3 A continuous collector current, and 1.6 W power dissipation at 25°C ambient. It features 80–300 DC current gain (h_FE) at I_C = 1–3 A, 0.4–1.1 V V_CE(sat), and 100 MHz transition frequency, used in relay drivers and voltage regulation circuits.

For engineers reviewing the STN724 datasheet, STN724 pinout, STN724 application, or STN724 equivalent, key selection criteria include its SOT-223 thermal resistance (78 °C/W), rugged Planar process construction, low saturation voltage under 3 A load, and suitability for medium-current switching in industrial control and power management systems.

Technical Context

The STN724 operates as a general-purpose NPN switch with defined safe operating area under pulsed and DC conditions. Its Planar technology ensures stable h_FE across I_C = 100 mA to 3 A and supports reliable turn-on/turn-off in resistive-load switching applications.

It exhibits V_(BR)CEO = 30 V (I_C = 10 mA), V_(BR)CBO = 60 V (I_E = 0), and V_BE(sat) = 1.2 V at I_C = 2 A / I_B = 100 mA - parameters critical for base drive sizing and breakdown margin in 24 V relay and regulator designs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - maximum collector-emitter voltage before breakdown with base open; sets upper rail limit for 24 V system switches
I_C (continuous)	3 A - sustained collector current capability; supports relay coils up to ~200 Ω at 24 V
P_tot	1.6 W at T_amb = 25°C - defines heatsinking requirement on PCB with 1 cm² copper area
h_FE	80–300 - current gain range at V_CE = 2 V; enables robust base drive design across production spread
V_CE(sat)	0.4–1.1 V - low saturation voltage reduces conduction loss and self-heating at full load
f_T	100 MHz - usable for moderate-speed switching (e.g., <50 kHz PWM) with predictable gain roll-off
R_thj-amb	78 °C/W - thermal resistance from junction to ambient on standard PCB; determines max junction temp rise under load

Pinout & Package

SOT-223 package: surface-mount, thermally enhanced 4-pin outline with exposed collector tab (pin 2). Pin 1 = emitter, pin 2 = collector (tab), pin 3 = base, pin 4 = collector (tab tie).

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Current return path; connected to ground or low-side reference in common-emitter switch
Pin 2 & Pin 4	Collector (tab)	Primary current output and thermal interface; must be soldered to ≥1 cm² copper pour for rated P_tot
Pin 3	Base	Control input; requires ~100 mA drive for full 3 A saturation per h_FE min of 30

Key Features

Feature	Design Value
Planar silicon process	Rugged construction with controlled doping profile; ensures consistent h_FE and breakdown performance across temperature and life cycle
SOT-223 thermal performance	78 °C/W R_thj-amb on 1 cm² PCB - enables higher continuous current than SOT-89 without external heatsink
Low V_CE(sat) at high I_C	0.7 V typical at I_C = 2 A / I_B = 100 mA - minimizes power loss and improves efficiency in 12–24 V switching loads
ECOPACK® compliance	Lead-free second-level interconnect; meets JEDEC JESD97 marking and RoHS requirements for industrial assembly

Applications

Industrial Relay Driver

Linear Voltage Regulator Pass Element

Use Scenario: Driving 24 VDC industrial relays with coil resistance 50–200 Ω in PLC output modules.

IC Role / Device Role / Timing Role: NPN switch in common-emitter configuration, sinking relay coil current to ground.

Use Value: 3 A I_C rating and 0.4 V V_CE(sat) ensure minimal dropout and heat generation during continuous duty cycling.

Use Scenario: Series pass transistor in adjustable 3–24 V linear regulators powering analog sensors or microcontrollers.

IC Role / Device Role / Timing Role: Current-amplifying element controlled by error amplifier feedback loop.

Use Value: High h_FE (min 80 at 1 A) reduces base drive burden; 150 °C T_J(max) supports operation under thermal stress.

DC Motor On/Off Control

Power Supply Sequencing Switch

Use Scenario: Enabling/disabling small DC motors (e.g., fans, actuators) in HVAC control panels.

IC Role / Device Role / Timing Role: Low-frequency (≤10 kHz) unidirectional switch in high-side or low-side configuration.

Use Value: 100 MHz f_T and fast switching times (<1 µs t_on/t_off) allow clean edge transitions without shoot-through risk.

Use Scenario: Controlled power-up sequencing of multiple voltage rails in embedded instrumentation.

IC Role / Device Role / Timing Role: Soft-start or enable-controlled current source limiting inrush into downstream capacitors.

Use Value: Defined SOA curve (Figure 8) permits safe operation during transient overloads up to 6 A peak for 5 ms.

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
MJD127	V_CEO = 80 V, I_C = 2 A, P_tot = 1.5 W, TO-252 package	Higher voltage rating but lower current and thermal performance than STN724	Preferred where >30 V rail isolation is required and PCB space allows DPAK footprint
ZTX653	V_CEO = 60 V, I_C = 2 A, P_tot = 1 W, SOT-89 package	Same marking prefix family but lower power and smaller package than SOT-223	Used when board layout constraints favor SOT-89 and 2 A load is sufficient

Compared with MJD127 and ZTX653, STN724 delivers superior current handling (3 A) and thermal dissipation (1.6 W / 78 °C/W) in the SOT-223 form factor, making it optimal for compact, high-reliability 24 V industrial switching where both current and thermal margin are critical.

Availability

STN724 is available at Aetrix Electronics and suitable for industrial relay drivers, linear voltage regulators, DC motor controls, and power supply sequencing requiring stable component supply and long-term manufacturability.

Supply support for STN724 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 STN724 belongs to ST's legacy bipolar transistor product line, engineered for ruggedness and consistency in medium-power linear and switching applications across harsh industrial environments.

FAQ

What is the maximum continuous collector current for STN724 at 70°C ambient temperature?

At T_amb = 70°C, derated collector current is approximately 2.2 A, calculated using P_tot = 1.6 W and R_thj-amb = 78 °C/W: T_J = 70 + (1.6 × 78) = 194.8°C exceeds 150°C rating, so I_C must be reduced to maintain T_J ≤ 150°C. Per thermal calculation, max I_C ≈ 2.2 A assuming V_CE(sat) ≈ 0.7 V.

Is STN724 suitable for use in automotive applications?

No - STN724 is not qualified to AEC-Q101 or automotive grade standards. ST's official documentation states non-automotive-grade products may only be used in automotive applications at the user's own risk, and this device lacks specified PPAP, qualification testing, or extended temperature validation beyond –65°C to +150°C storage.

How does the SOT-223 package improve thermal performance over SOT-89 for STN724?

SOT-223 provides 78 °C/W R_thj-amb versus 89 °C/W for SOT-89 (STF724), due to larger copper area and integrated thermal tab. This 12.4% lower thermal resistance allows ~15% higher continuous power dissipation on identical PCB layouts, directly supporting 3 A vs. 2 A rated current.

Can STN724 replace STF724 in existing designs?

Yes, with mechanical and thermal considerations: both share identical electrical specs (V_CEO, h_FE, V_CE(sat)), but STN724's SOT-223 requires different land pattern and offers better thermal performance. Layout redesign is needed for footprint and copper pour; no circuit revalidation is required if thermal margins are verified.

STN724 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-261-4, TO-261AA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 1.1V @ 150mA, 3A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 100mA, 2V

Power - Max:: 1.6 W

Frequency - Transition:: 100MHz

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-223

STN724 FAQ

1.How can I place an order for STN724 through Aetrix?

Please submit a Request for Quotation (RFQ) for STN724 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 STN724 reliable?

The price and inventory of STN724 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STN724 is usually 5 days.

3.What payment methods are accepted for STN724?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STN724 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STN724?

STN724 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STN724 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 STN724?

For technical support, including STN724 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STN724 requirements.

6.How does Aetrix verify that STN724 is sourced from the original manufacturer or authorized distributors?

All STN724 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 STN724 meets industry standards.

7.What is the process for return or replacement of STN724?

All STN724 units undergo pre-shipment inspection (PSI). If there is an issue with STN724, 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 STN724 part is unused and in its original packaging.

Return procedure for STN724:

1.Submit a request within 90 days.

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

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