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

STMicroelectronics STD826T4

Name: STD826T4
Brand: STMicroelectronics
SKU: STD826T4
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STD826T4

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

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

Datasheet:: STD826T4.pdf

Description:: TRANS PNP 30V 3A DPAK

Quantity:: RFQ Add To RFQ list

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Product details

Overview

STD826T4 from STMicroelectronics is a PNP medium-power bipolar junction transistor in DPAK (TO-252) package, rated for -30 V V_CEO, -3 A I_C, 15 W P_TOT at T_C = 25°C, with h_FE ≥ 80 at I_C = -1 A, used in relay driver and voltage regulation circuits.

For engineers reviewing the STD826T4 datasheet, STD826T4 pinout, STD826T4 application, or STD826T4 equivalent, key selection criteria include V_CEO derating at elevated case temperature, saturation voltage under pulsed load conditions, thermal resistance (R_thJ-case = 8.33°C/W), and compliance with ECOPACK® lead-free packaging requirements.

Technical Context

The STD826T4 operates as a medium-power PNP switching transistor with planar technology construction, supporting DC and pulsed operation up to -6 A I_CM (t_P < 5 ms). Its breakdown ratings-V_CBO = -60 V, V_CEO = -30 V, V_EBO = -5 V-define safe operating limits under open-base, open-emitter, and open-collector biasing.

Electrical behavior is characterized by V_CE(sat) = -0.7 V at I_C = -2 A / I_B = -100 mA, f_T = 100 MHz at V_CE = -10 V / I_C = -0.1 A, and h_FE ranging from 30 to 300 depending on collector current and V_CE.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-30 V - Maximum collector-emitter voltage before avalanche under open-base condition; sets upper limit for switching rail voltage in relay or regulator designs.
I_C	-3 A - Continuous DC collector current rating at T_C = 25°C; defines steady-state load drive capability.
P_TOT	15 W - Total power dissipation at case temperature 25°C; requires heatsinking above ~5 W in practical PCB layouts.
V_CE(sat)	-0.7 V @ I_C = -2 A / I_B = -100 mA - Low saturation voltage enables efficient switching with <1.4 W conduction loss at rated current.
h_FE	80 min @ I_C = -1 A / V_CE = -2 V - Sufficient DC gain to drive with modest base current, reducing driver-stage complexity.
f_T	100 MHz - Transition frequency confirms suitability for low-to-moderate speed switching (e.g., <100 kHz PWM), not RF amplification.
R_thJ-case	8.33 °C/W - Junction-to-case thermal resistance; determines temperature rise per watt dissipated when mounted on copper pad or heatsink.

Pinout & Package

DPAK (TO-252) surface-mount package with exposed drain-connected tab (pin 3), standard three-terminal configuration: emitter (pin 1), base (pin 2), collector (pin 3/tab). Requires minimum 100 mm² copper pour for thermal performance.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current source terminal for PNP operation	Connected to higher potential rail; base-emitter forward bias initiates conduction.
2 (Base)	Control input for minority-carrier injection	Receives negative current relative to emitter to turn device ON; requires current-limiting resistor.
3 (Collector / Tab)	Main current sink and thermal path	Electrically connected to collector; must be soldered to large copper area for heat dissipation and EMI control.

Key Features

Feature	Design Value
ECOPACK® lead-free packaging	Complies with RoHS Directive 2002/95/EC and JEDEC JESD97; marked on inner box label for traceability.
High ruggedness via planar process	Enables reliable operation under repetitive surge conditions (I_CM = -6 A, t_P < 5 ms) without secondary breakdown.
Low V_CE(sat) at high current	-1.1 V max at I_C = -3 A / I_B = -150 mA reduces conduction losses in linear or saturated switching applications.
Wide operating junction temperature	Rated for T_J = -65°C to +150°C; supports industrial ambient environments without derating below 125°C.

Applications

Relay Driver Circuit

Voltage Regulation Stage

Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules with microcontroller GPIO-level base control.

IC Role / Device Role / Timing Role: PNP switch providing high-side current sourcing to relay coil, enabling ground-referenced logic control.

Use Value: V_CE(sat) ≤ -0.7 V ensures >90% coil voltage delivery; h_FE ≥ 80 allows direct drive from 5 V MCU with 1 kΩ base resistor.

Use Scenario: Pass element in adjustable linear voltage regulator supplying 5 V/2 A to analog sensor subsystems.

IC Role / Device Role / Timing Role: Series pass transistor regulating output by dissipating excess input-output differential voltage.

Use Value: 15 W P_TOT and R_thJ-case = 8.33°C/W support stable 2 A output at 12 V input with 25°C/W heatsink.

DC Motor On/Off Control

Power Supply Sequencing

Use Scenario: Enabling/disabling brushed DC motors (e.g., 24 V/1.5 A fans) in HVAC control units using PWM-enabled base drive.

IC Role / Device Role / Timing Role: High-side switch controlling motor power rail; operated in saturation for minimal loss during ON state.

Use Value: f_T = 100 MHz ensures fast turn-on/turn-off (t_on/t_off < 1 μs), minimizing switching loss at 20 kHz PWM frequencies.

Use Scenario: Controlling power-up sequence of dual-rail FPGA core/I/O supplies where 3.3 V must stabilize before 1.2 V activation.

IC Role / Device Role / Timing Role: Delayed-enable switch isolating downstream rail until upstream supply reaches threshold.

Use Value: V_CEO = -30 V accommodates reverse-biased blocking during sequencing transients; I_C = -3 A handles peak inrush currents.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD2955T4	V_CEO = -60 V, I_C = -12 A, P_TOT = 30 W, R_thJ-case = 4.2°C/W - higher voltage/current rating, lower thermal resistance.	Supports higher load currents and wider input voltage range; suitable for 48 V systems or higher-power relays.	Select when >3 A continuous current or >30 V rail voltage is required; footprint differs (TO-252-3 vs. TO-252-3 same but internal layout optimized).
BDX53C	V_CEO = -100 V, I_C = -8 A, P_TOT = 60 W, h_FE = 20–60 - higher breakdown, lower gain, larger TO-126 package.	Designed for high-voltage linear amplification; less suited for fast switching due to lower f_T and higher V_CE(sat).	Prefer for legacy through-hole designs or high-V_CE analog applications; not drop-in compatible due to package and gain profile.

Compared with MJD2955T4 and BDX53C, the STD826T4 offers optimal balance of cost, thermal performance, and gain for 24 V relay/motor control at ≤3 A, while avoiding over-specification that increases board area and cost.

Availability

STD826T4 is available at Aetrix Electronics and suitable for relay driver circuits, linear voltage regulation stages, DC motor on/off control, and power supply sequencing requiring stable component supply across industrial automation and embedded control programs.

Supply support for STD826T4 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, discrete devices, and MEMS sensors for industrial, automotive, and consumer markets.

The STD826 series belongs to ST's medium-power bipolar transistor product line, engineered specifically for robust, cost-effective switching in industrial control, power management, and electromechanical interface applications.

FAQ

Is STD826T4 RoHS-compliant and lead-free?

Yes, STD826T4 is manufactured in STMicroelectronics' ECOPACK® package with lead-free second-level interconnect, compliant with EU Directive 2002/95/EC (RoHS) and JEDEC Standard JESD97. The lead-free status is marked on both the package and inner box label.

What is the maximum allowable case temperature for continuous operation?

The maximum case temperature for continuous operation is determined by derating P_TOT linearly above 25°C. With R_thJ-case = 8.33°C/W and T_J(max) = 150°C, T_C must not exceed 130°C to maintain 15 W rating; full derating applies beyond that point.

Can STD826T4 be used in linear amplifier configurations?

While electrically capable of linear operation, STD826T4 is optimized for switching applications. Its f_T = 100 MHz and moderate h_FE variation make it unsuitable for high-fidelity audio or precision analog amplification; use dedicated linear transistors like BC557 or BD139 instead.

Does STD826T4 require a heatsink in typical relay driver applications?

In typical 24 V/1 A relay driver applications with 100% duty cycle, power dissipation is ~0.7 W (V_CE(sat) × I_C). A minimal 25 mm² copper pour suffices; no external heatsink is required unless ambient exceeds 70°C or duty cycle approaches 100% at >2 A loads.

STD826T4 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:: PNP

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:: 15 W

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DPAK

STD826T4 FAQ

1.How can I place an order for STD826T4 through Aetrix?

Please submit a Request for Quotation (RFQ) for STD826T4 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 STD826T4 reliable?

The price and inventory of STD826T4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STD826T4 is usually 5 days.

3.What payment methods are accepted for STD826T4?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STD826T4 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STD826T4?

STD826T4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STD826T4 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 STD826T4?

For technical support, including STD826T4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STD826T4 requirements.

6.How does Aetrix verify that STD826T4 is sourced from the original manufacturer or authorized distributors?

All STD826T4 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 STD826T4 meets industry standards.

7.What is the process for return or replacement of STD826T4?

All STD826T4 units undergo pre-shipment inspection (PSI). If there is an issue with STD826T4, 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 STD826T4 part is unused and in its original packaging.

Return procedure for STD826T4:

1.Submit a request within 90 days.

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

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