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

STMicroelectronics STD724T4

Name: STD724T4
Brand: STMicroelectronics
SKU: STD724T4
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STD724T4

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Datasheet:: STD724T4.pdf

Description:: TRANS NPN 30V 3A DPAK

Quantity:: RFQ Add To RFQ list

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Product details

Overview

STD724T4 from STMicroelectronics is a surface-mount NPN medium-power transistor in DPAK (TO-252) package, rated for 30 V V_CEO, 3 A continuous collector current, and 15 W total dissipation at T_C = 25°C; used in relay drivers and linear voltage regulation circuits.

For engineers reviewing the STD724T4 datasheet, STD724T4 pinout, STD724T4 application, or STD724T4 equivalent, key selection criteria include V_CE(sat) ≤ 0.7 V at I_C = 2 A/I_B = 100 mA, h_FE ≥ 80 at I_C = 1 A, f_T = 100 MHz, thermal resistance R_thj-amb ≤ 8.33 °C/W, and ECOPACK® lead-free compliance.

Technical Context

This NPN bipolar junction transistor uses planar technology to deliver rugged switching and linear operation with low saturation voltage and stable DC gain across operating current range. It supports pulsed collector currents up to 6 A (t_P < 5 ms) and withstands V_CBO = 60 V and V_EBO = 5 V.

Designed for medium-power surface-mount applications, it operates with junction temperatures from –65°C to +150°C and features a thermally optimized DPAK footprint for PCB-level heat transfer. Its f_T of 100 MHz enables use in moderate-speed switching and analog amplification where bandwidth exceeds audio range.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - Maximum safe collector-emitter voltage under open-base condition; defines upper limit for switching or regulation headroom.
I_C	3 A - Continuous DC collector current rating; determines maximum load drive capability in relay or regulator stages.
V_CE(sat)	0.7 V @ I_C=2 A/I_B=100 mA - Low saturation voltage minimizes conduction loss and self-heating in switching applications.
h_FE	80 @ I_C=1 A/V_CE=2 V - Sufficient DC current gain for direct base drive from microcontrollers or logic buffers without external amplification.
f_T	100 MHz - Transition frequency confirms usable bandwidth for fast-switching control loops and RF-adjacent signal conditioning.
R_thj-amb	8.33 °C/W - Thermal resistance from junction to ambient (unheatsinked); sets baseline for PCB copper area and airflow requirements.

Pinout & Package

STD724T4 is housed in a DPAK (TO-252) surface-mount package with exposed drain tab (pin 2) for thermal and electrical connection to PCB ground plane. The package complies with JEDEC MO-236 and ECOPACK® environmental standards.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit path for majority carriers	Connected to circuit common/ground; low-impedance return node for load current.
2 (Collector / Tab)	Main current input and thermal interface	Electrically and thermally tied to large copper pour; must be soldered to PCB for thermal performance and current handling.
3 (Base)	Control terminal for minority carrier injection	Receives current-limited drive signal; requires series resistor to limit I_B ≤ 1 A peak per datasheet.

Key Features

Feature	Design Value
Surface-mount DPAK package	Enables automated assembly and high thermal conductivity via exposed collector tab bonded directly to PCB copper.
ECOPACK® lead-free construction	Meets RoHS Directive 2002/95/EC and EU packaging requirements without compromising solderability or reliability.
V_CE(sat) ≤ 0.7 V @ 2 A	Reduces power loss to ≤1.4 W at full load, easing thermal design in compact relay driver modules.
h_FE ≥ 80 @ 1 A	Supports direct GPIO drive from 3.3 V or 5 V MCUs with ≤12.5 mA base current requirement.

Applications

Relay Driver Circuit

Voltage Regulation Stage

Use Scenario: Driving 12 V/1 A electromagnetic relay coil in industrial PLC output modules.

IC Role / Device Role / Timing Role: NPN switch controlling coil current path; turns on/off within <10 µs based on MCU GPIO signal.

Use Value: Low V_CE(sat) limits coil-side voltage drop to <0.7 V, ensuring reliable relay pull-in at minimum supply voltage.

Use Scenario: Pass transistor in linear 5 V/2 A adjustable regulator using LM317 feedback network.

IC Role / Device Role / Timing Role: Series pass element dissipating excess input-output differential as heat; operates in active region.

Use Value: 15 W power rating and DPAK thermal path support 2 A output at 7 V input–5 V output (ΔV = 2 V → P_D = 4 W).

DC Motor On/Off Control

Power Supply Sequencing

Use Scenario: Enabling/disabling 24 V brushed DC motor in HVAC actuator subsystem.

IC Role / Device Role / Timing Role: High-side or low-side switch (with appropriate biasing) managing motor start/stop transients.

Use Value: 6 A pulsed current rating accommodates 3× stall current surges during motor startup without second breakdown.

Use Scenario: Controlled turn-on of auxiliary 3.3 V rail after main 12 V rail stabilizes in multi-rail embedded power system.

IC Role / Device Role / Timing Role: Delayed-enable switch activated by RC-timed base drive; provides sequencing margin before downstream ICs power up.

Use Value: Stable h_FE and low leakage (I_CEO ≤ 100 µA) ensure precise timing window and minimal standby current.

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
MJD127G	V_CEO = 100 V, I_C = 2 A, h_FE = 30–120 (min 30), R_thj-amb = 10 °C/W	Higher voltage rating but lower current and thermal performance; suited for higher-voltage, lower-current loads.	Select when V_IN > 30 V is required and 2 A max load suffices.
STN8300	V_CEO = 40 V, I_C = 4 A, V_CE(sat) = 0.5 V @ 3 A, f_T = 120 MHz	Higher current, lower saturation voltage, and faster frequency response; newer process with improved efficiency.	Preferred for new designs needing higher current or lower conduction loss; pin-compatible DPAK replacement.

Compared with MJD127G, STD724T4 offers higher current and better thermal resistance but lower voltage rating; versus STN8300, it trades slightly higher V_CE(sat) and lower f_T for proven field reliability in legacy industrial systems.

Availability

STD724T4 is available at Aetrix Electronics and suitable for relay driver circuits, linear voltage regulation stages, and DC motor on/off control requiring stable component supply and long-term industrial availability.

Supply support for STD724T4 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.

STD724T4 belongs to ST's legacy bipolar power transistor product line, engineered for robustness and manufacturability in medium-power linear and switching applications across industrial controls and power supplies.

FAQ

Is STD724T4 still in active production?

No-STD724T4 is marked "Obsolete Product(s)" in the official STMicroelectronics datasheet (Rev 2, October 2005). However, Aetrix Electronics maintains legacy inventory with full traceability and supports extended-life procurement for industrial maintenance and repair programs.

What is the recommended PCB layout for thermal performance?

Use ≥ 4 cm² of 2 oz copper connected directly to the collector (pin 2) tab via multiple thermal vias to inner/outer ground planes. Avoid solder mask over the tab area and ensure ≥ 0.5 mm clearance from adjacent traces to prevent creepage failure at 30 V.

Can STD724T4 replace a TO-220 transistor in existing designs?

Yes-if mechanical mounting allows DPAK footprint adaptation. Electrical characteristics match typical TO-220 NPN transistors (e.g., BD139), but thermal performance depends on PCB copper area rather than heatsink attachment; derate power by 20% if copper area is <3 cm².

Does STD724T4 require a base current limiting resistor?

Yes-base current must be limited to ≤100 mA for continuous operation and ≤2 A peak (t_P < 5 ms). For 5 V MCU GPIO driving h_FE ≈ 80 at I_C = 2 A, a 33 Ω ±5% resistor ensures I_B ≈ 60 mA and prevents thermal runaway or secondary breakdown.

STD724T4 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-252-3, DPAK (2 Leads + Tab), SC-63

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:: 80 @ 1A, 2V

Power - Max:: 15 W

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DPAK

STD724T4 FAQ

1.How can I place an order for STD724T4 through Aetrix?

Please submit a Request for Quotation (RFQ) for STD724T4 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 STD724T4 reliable?

The price and inventory of STD724T4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STD724T4 is usually 5 days.

3.What payment methods are accepted for STD724T4?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STD724T4 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STD724T4?

STD724T4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STD724T4 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 STD724T4?

For technical support, including STD724T4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STD724T4 requirements.

6.How does Aetrix verify that STD724T4 is sourced from the original manufacturer or authorized distributors?

All STD724T4 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 STD724T4 meets industry standards.

7.What is the process for return or replacement of STD724T4?

All STD724T4 units undergo pre-shipment inspection (PSI). If there is an issue with STD724T4, 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 STD724T4 part is unused and in its original packaging.

Return procedure for STD724T4:

1.Submit a request within 90 days.

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

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