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

onsemi BD676A

Name: BD676A
Brand: onsemi
SKU: BD676A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD676A

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: BD676A.pdf

Description:: TRANS PNP DARL 45V 4A TO-126

Quantity:: RFQ Add To RFQ list

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Inventory:3,070

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Product details

Overview

BD676A from onsemi is a plastic medium-power silicon PNP Darlington transistor designed for complementary general-purpose amplifier output stages. It features 45 V_CEO, 4.0 A I_C, 40 W power dissipation at T_C = 25 °C, h_FE ≥ 750 at I_C = 1.5 A, and TO-225 package with emitter-base-collector pinout. It is used in linear audio output stages and relay drivers requiring high DC gain and medium power switching.

For engineers reviewing the BD676A datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO rating, saturation voltage under specified I_C/I_B, thermal resistance (R_θJC = 3.13 °C/W), and complementary pairing with NPN counterparts like BD675/BD675A.

Technical Context

The BD676A integrates two PNP transistors in monolithic Darlington configuration to achieve high DC current gain while maintaining medium-power handling capability. Its structure enables low base drive requirements and stable operation in Class AB amplifier outputs and inductive load switching.

It operates within −55 °C to +150 °C junction temperature range and exhibits V_CE(sat) ≤ 2.5 V at I_C = 1.5 A / I_B = 30 mA, with V_BE(on) ≈ 2.5 V under same conditions. Thermal derating begins above 25 °C at 0.32 W/°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 Vdc - Maximum collector-emitter voltage before breakdown; defines safe operating voltage ceiling in amplifier or switch applications.
I_C	4.0 Adc - Continuous collector current rating; supports medium-power loads such as 20–30 W audio outputs or solenoid drivers.
P_D @ T_C = 25 °C	40 W - Total device dissipation at case temperature 25 °C; requires heatsinking for sustained operation above ambient.
h_FE	≥ 750 at I_C = 1.5 A, V_CE = 3.0 V - High DC current gain reduces required base drive current, easing driver stage design.
R_θJC	3.13 °C/W - Junction-to-case thermal resistance; determines minimum heatsink requirement for given power and temperature rise.
V_CE(sat)	≤ 2.5 V at I_C = 1.5 A, I_B = 30 mA - Low saturation voltage minimizes conduction loss and heat generation in switching mode.

Pinout & Package

BD676A uses the TO-225 package (Case 77−09, Style 1), a 3-lead plastic power package with backside collector tab (pins 2 and 4 both connected to collector). The package provides mechanical robustness and thermal path via the metal tab.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Main current exit terminal; connects to load return or ground reference in common-emitter configurations.
2, 4	Collector	Shared collector terminals (pins 2 and 4 are internally tied); provides dual connection points for high-current routing and improved thermal contact to heatsink.
3	Base	Control input; drives Darlington pair with low current due to high h_FE; requires current-limiting resistor in series.

Key Features

Feature	Design Value
High DC Current Gain	h_FE ≥ 750 enables <1 mA base drive for 1.5 A collector current, reducing driver complexity and power consumption.
Monolithic Darlington Construction	Integrated dual-transistor die ensures matched characteristics, eliminates external wiring errors, and improves reliability over discrete pairs.
Complementary Pairing	Designed as PNP counterpart to BD675/BD675A series, enabling balanced push-pull amplifier topologies without gain mismatch.
Pb-Free & RoHS Compliant	Meets environmental compliance requirements for industrial and consumer electronics manufacturing without lead-based solder concerns.

Applications

Audio Power Amplifier Output Stage	Relay and Solenoid Driver
Use Scenario: Final output stage in 10–25 W linear audio amplifiers driving 4–8 Ω speakers. IC Role / Device Role / Timing Role: PNP Darlington output transistor delivering high-current, low-distortion signal swing in Class AB topology. Use Value: High h_FE and low V_CE(sat) reduce driver stage loading and conduction losses, improving thermal efficiency and THD performance.	Use Scenario: Driving 12–24 V DC relays or 2–5 A solenoids in industrial control panels and HVAC systems. IC Role / Device Role / Timing Role: Medium-power switch controlling inductive loads with flyback protection. Use Value: 45 V_CEO margin accommodates inductive kickback; 4.0 A rating supports peak coil currents without secondary breakdown.
DC Motor Speed Controller	Linear Voltage Regulator Pass Element
Use Scenario: H-bridge half-bridge or single-ended driver for 12–24 V brushed DC motors in automation equipment. IC Role / Device Role / Timing Role: High-gain PNP switch regulating motor current in analog PWM or linear control schemes. Use Value: Monolithic construction ensures consistent turn-on/turn-off behavior across temperature, critical for closed-loop speed stability.	Use Scenario: Series pass element in adjustable linear regulators delivering up to 3 A output current. IC Role / Device Role / Timing Role: Power transistor dissipating excess voltage between unregulated input and regulated output. Use Value: 40 W dissipation capability and R_θJC = 3.13 °C/W allow stable operation with modest heatsinking at 2–3 A load currents.

Audio Power Amplifier Output Stage

Relay and Solenoid Driver

Use Scenario: Final output stage in 10–25 W linear audio amplifiers driving 4–8 Ω speakers.

IC Role / Device Role / Timing Role: PNP Darlington output transistor delivering high-current, low-distortion signal swing in Class AB topology.

Use Value: High h_FE and low V_CE(sat) reduce driver stage loading and conduction losses, improving thermal efficiency and THD performance.

Use Scenario: Driving 12–24 V DC relays or 2–5 A solenoids in industrial control panels and HVAC systems.

IC Role / Device Role / Timing Role: Medium-power switch controlling inductive loads with flyback protection.

Use Value: 45 V_CEO margin accommodates inductive kickback; 4.0 A rating supports peak coil currents without secondary breakdown.

DC Motor Speed Controller

Linear Voltage Regulator Pass Element

Use Scenario: H-bridge half-bridge or single-ended driver for 12–24 V brushed DC motors in automation equipment.

IC Role / Device Role / Timing Role: High-gain PNP switch regulating motor current in analog PWM or linear control schemes.

Use Value: Monolithic construction ensures consistent turn-on/turn-off behavior across temperature, critical for closed-loop speed stability.

Use Scenario: Series pass element in adjustable linear regulators delivering up to 3 A output current.

IC Role / Device Role / Timing Role: Power transistor dissipating excess voltage between unregulated input and regulated output.

Use Value: 40 W dissipation capability and R_θJC = 3.13 °C/W allow stable operation with modest heatsinking at 2–3 A load currents.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP Darlington transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BD676G	Same V_CEO (45 V), same package, but h_FE min = 750 only at I_C = 1.5 A; no "A" suffix variant specification for higher h_FE at elevated I_C.	Identical use cases; slightly lower guaranteed gain consistency at higher currents compared to BD676A.	Select BD676G when cost sensitivity outweighs need for guaranteed h_FE at 2.0 A test condition.
MJE700	60 V_CEO, 4 A I_C, TO-225, h_FE ≥ 750 at I_C = 1.5 A - higher voltage rating but not complementary to BD675 series.	Suitable for higher-voltage switching where BD676A's 45 V limit is insufficient; not drop-in for BD676A in matched complementary designs.	Choose MJE700 when system requires >45 V blocking capability and complementary pairing is not required.

Compared with BD676G and MJE700, the BD676A offers tighter h_FE specification at higher test current (2.0 A vs 1.5 A) and guaranteed compatibility with BD675A in symmetrical amplifier designs - making it preferred for precision linear output stages where gain matching matters.

Availability

BD676A is available at Aetrix Electronics and suitable for audio amplifier output stages, relay/solenoid drivers, and DC motor controllers requiring stable component supply and long-term industrial availability.

Supply support for BD676A 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, serving automotive, industrial, cloud, and IoT markets with discrete, analog, and logic solutions.

The BD676A belongs to onsemi's plastic medium-power Darlington transistor family, engineered for reliable linear and switching operation in general-purpose amplifier and power control applications where high DC gain and thermal robustness are essential.

FAQ

What is the maximum collector-emitter voltage rating for BD676A?

The BD676A has a maximum collector-emitter voltage (V_CEO) rating of 45 Vdc, verified per the onsemi BD676/D datasheet Rev. 15. This rating applies under standard test conditions (I_C = 50 mA, I_B = 0) and defines the absolute maximum voltage the device can withstand before breakdown. Exceeding this value risks permanent damage to the BD676A.

Is BD676A pin-compatible with BD676G?

Yes, BD676A is pin-compatible with BD676G - both use the TO-225 package (Case 77−09, Style 1) with identical pin 1 (emitter), pins 2/4 (collector), and pin 3 (base) assignments. However, BD676A specifies h_FE ≥ 750 at I_C = 2.0 A, whereas BD676G guarantees it only at I_C = 1.5 A; the BD676A thus offers enhanced gain assurance at higher currents.

What is the thermal resistance junction-to-case for BD676A?

The BD676A has a thermal resistance junction-to-case (R_θJC) of 3.13 °C/W, as specified in the onsemi BD676/D datasheet. This value enables calculation of junction temperature rise above case temperature (ΔT_J = P_D × R_θJC) and informs heatsink sizing for continuous operation at rated power dissipation.

Does BD676A support complementary amplifier designs?

Yes, BD676A is explicitly designed as the PNP complement to the NPN BD675 and BD675A transistors. The onsemi datasheet confirms complementary pairing across the BD675/675A–BD676/676A series, enabling matched gain, voltage, and thermal characteristics in push-pull and Class AB amplifier output stages using BD676A.

What is the base-emitter on voltage for BD676A under typical operating conditions?

The BD676A exhibits a base-emitter on voltage (V_BE(on)) of approximately 2.5 Vdc when operated at I_C = 2.0 A and V_CE = 3.0 Vdc, per the Electrical Characteristics table in the official BD676/D datasheet. This relatively high V_BE reflects the Darlington configuration's two-series base-emitter junctions and must be accounted for in base drive circuit design.

BD676A Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP - Darlington

Current - Collector (Ic) (Max):: 4 A

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 2.8V @ 40mA, 2A

Current - Collector Cutoff (Max):: 500µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 750 @ 2A, 3V

Power - Max:: 40 W

Frequency - Transition:: -

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126

BD676A FAQ

1.How can I place an order for BD676A through Aetrix?

Please submit a Request for Quotation (RFQ) for BD676A 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 BD676A reliable?

The price and inventory of BD676A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD676A is usually 5 days.

3.What payment methods are accepted for BD676A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD676A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD676A?

BD676A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD676A 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 BD676A?

For technical support, including BD676A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD676A requirements.

6.How does Aetrix verify that BD676A is sourced from the original manufacturer or authorized distributors?

All BD676A 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 BD676A meets industry standards.

7.What is the process for return or replacement of BD676A?

All BD676A units undergo pre-shipment inspection (PSI). If there is an issue with BD676A, 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 BD676A part is unused and in its original packaging.

Return procedure for BD676A:

1.Submit a request within 90 days.

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

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