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

onsemi BD676

Name: BD676
Brand: onsemi
SKU: BD676
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD676

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BD676.pdf

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

Quantity:: RFQ Add To RFQ list

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Inventory:8,869

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Product details

Overview

BD676 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 collector current, 40 W power dissipation at T_C = 25 °C, 750 minimum DC current gain (h_FE), and TO-225 package with emitter-base-collector pinout. It is used in audio output stages and motor drive circuits requiring high-current switching with low base drive.

For engineers reviewing the BD676 datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO rating, h_FE consistency at I_C = 1.5 A, V_CE(sat) under specified drive conditions, thermal resistance (R_JC = 3.13 °C/W), and Pb-free RoHS-compliant packaging for industrial and consumer-grade power amplifiers.

Technical Context

The BD676 operates as a monolithic PNP Darlington pair, integrating two cascaded PNP transistors to achieve high current gain while maintaining single-package simplicity. Its structure enables low base drive requirements (I_B ≤ 0.1 A) for full collector current conduction and supports linear and switching operation in complementary symmetry amplifier topologies.

It is explicitly paired with NPN counterparts BD675/675A/677/677A/679/679A/681 for push-pull configurations. The device's safe operating area (SOA) is defined by thermal limits at T_C = 25 °C and secondary breakdown constraints, with derating to 0 W at T_C = 150 °C per the 0.32 W/°C slope.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 Vdc - Maximum collector-emitter voltage before breakdown; defines usable supply rail headroom in Class AB amplifiers.
I_C	4.0 Adc - Continuous collector current capability; sets peak load current handling in motor driver or audio output stages.
P_D @ T_C = 25°C	40 W - Total device dissipation limit at case temperature 25°C; determines heatsink sizing baseline.
h_FE	750 min @ I_C = 1.5 A, V_CE = 3.0 V - High DC current gain reduces required base drive current in driver circuits.
R_JC	3.13 °C/W - Junction-to-case thermal resistance; critical for calculating junction temperature rise under load.
V_CE(sat)	2.5 V max @ I_C = 1.5 A, I_B = 30 mA - Saturation voltage impacts conduction loss and thermal load in switching applications.
T_J Range	−55 to +150 °C - Operating junction temperature range; supports industrial ambient and thermally stressed PCB layouts.

Pinout & Package

BD676 is housed in a TO-225 package (Case 77-09, Style 1), with a metal tab acting as the collector (pins 2 and 4), emitter at pin 1, and base at pin 3. The package is Pb-free (G suffix), RoHS compliant, and rated for surface-mount or through-hole mounting with mechanical anchoring via the collector tab.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Main current exit path; connects to ground or negative rail in common-emitter configurations.
Pins 2 & 4	Collector	Shared collector terminals; electrically tied internally; used for thermal coupling to heatsink.
Pin 3	Base	Control input; requires current-limited drive due to Darlington's high h_FE and V_BE(on) ≈ 2.5 V.

Key Features

Feature	Design Value
Monolithic Darlington construction	Single-die integration eliminates external wiring, improves reliability, and ensures matched transistor characteristics.
High DC current gain (h_FE ≥ 750)	Reduces base drive circuit complexity and power consumption in high-current output stages.
TO-225 package with dual collector pins	Enables robust thermal transfer via collector tab while supporting mechanical stability on PCBs.
Pb-free and RoHS-compliant	Meets global environmental compliance requirements without compromising electrical or thermal performance.

Applications

Audio Power Amplifiers	Motor Drive Outputs
Use Scenario: Complementary Class AB output stage in stereo audio amplifiers delivering up to 20 W into 8 Ω loads. IC Role / Device Role / Timing Role: PNP Darlington output transistor providing high-current sourcing capability during positive half-cycle conduction. Use Value: Delivers low-distortion output with minimal base drive due to h_FE ≥ 750 and stable V_CE(sat) ≤ 2.5 V.	Use Scenario: H-bridge upper-leg switch in brushed DC motor controllers for industrial actuators. IC Role / Device Role / Timing Role: High-side PNP Darlington switch controlling motor current direction and braking via emitter-follower configuration. Use Value: Supports 4.0 A continuous motor current with thermal margin ensured by R_JC = 3.13 °C/W and 40 W dissipation rating.
Linear Power Supplies	Relay Drivers
Use Scenario: Pass transistor in adjustable linear regulators supplying up to 3 A for analog instrumentation rails. IC Role / Device Role / Timing Role: Series pass element regulating output voltage by varying V_CE under feedback control. Use Value: Maintains regulation stability across −55 to +150 °C junction range and handles 45 V input-to-output differential.	Use Scenario: High-current relay coil driver in PLC I/O modules requiring >2 A coil energization. IC Role / Device Role / Timing Role: Switching transistor enabling fast relay turn-on with low V_CE(sat) to minimize coil voltage drop. Use Value: Ensures reliable relay closure using only 30 mA base current, leveraging h_FE ≥ 750 for efficient drive.

Audio Power Amplifiers

Motor Drive Outputs

Use Scenario: Complementary Class AB output stage in stereo audio amplifiers delivering up to 20 W into 8 Ω loads.

IC Role / Device Role / Timing Role: PNP Darlington output transistor providing high-current sourcing capability during positive half-cycle conduction.

Use Value: Delivers low-distortion output with minimal base drive due to h_FE ≥ 750 and stable V_CE(sat) ≤ 2.5 V.

Use Scenario: H-bridge upper-leg switch in brushed DC motor controllers for industrial actuators.

IC Role / Device Role / Timing Role: High-side PNP Darlington switch controlling motor current direction and braking via emitter-follower configuration.

Use Value: Supports 4.0 A continuous motor current with thermal margin ensured by R_JC = 3.13 °C/W and 40 W dissipation rating.

Linear Power Supplies

Relay Drivers

Use Scenario: Pass transistor in adjustable linear regulators supplying up to 3 A for analog instrumentation rails.

IC Role / Device Role / Timing Role: Series pass element regulating output voltage by varying V_CE under feedback control.

Use Value: Maintains regulation stability across −55 to +150 °C junction range and handles 45 V input-to-output differential.

Use Scenario: High-current relay coil driver in PLC I/O modules requiring >2 A coil energization.

IC Role / Device Role / Timing Role: Switching transistor enabling fast relay turn-on with low V_CE(sat) to minimize coil voltage drop.

Use Value: Ensures reliable relay closure using only 30 mA base current, leveraging h_FE ≥ 750 for efficient drive.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BD676AG	Same V_CEO (45 V), higher h_FE test condition (I_C = 2.0 A vs. 1.5 A); identical package and pinout.	Optimized for higher-current saturation where h_FE consistency above 1.5 A matters.	Select BD676AG when designing for sustained >1.5 A collector current with tighter h_FE specification.
BD678G	Higher V_CEO (60 V), same I_C (4.0 A), same TO-225 package and pinout.	Suitable for 48 V bus systems or designs requiring additional voltage margin over BD676's 45 V rating.	Choose BD678G if system supply rails exceed 42 V or transient overvoltage immunity is critical.

Compared with BD676AG and BD678G, the BD676 offers the lowest V_CEO in its family but maintains identical thermal and current ratings-making it optimal for cost-sensitive 24–36 V applications where 45 V margin suffices and base drive efficiency is prioritized.

Availability

BD676 is available at Aetrix Electronics and suitable for audio power amplifiers, motor drive outputs, and linear power supplies requiring stable component supply and industrial-grade thermal reliability.

Supply support for BD676 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 manufacturer specializing in power management, analog, sensors, and discrete devices for automotive, industrial, and consumer markets.

The BD676 belongs to onsemi's plastic medium-power PNP Darlington transistor product line, engineered for complementary amplifier output stages and high-current switching where monolithic gain, thermal robustness, and Pb-free compliance are essential.

FAQ

What is the maximum collector-emitter voltage rating for BD676?

The BD676 has a maximum collector-emitter voltage (V_CEO) rating of 45 Vdc, verified per the onsemi BD676/D datasheet under test condition I_C = 50 mA and I_B = 0. This rating defines the absolute maximum supply voltage the BD676 can withstand in open-circuit or active-linear operation without breakdown. Exceeding this value risks permanent damage, and design margins should maintain at least 15–20% derating in real-world applications.

Is BD676 pin-compatible with BD676AG?

Yes, BD676 and BD676AG share identical TO-225 package dimensions, pinout (emitter-pin1, collector-pins2&4, base-pin3), and mechanical mounting. The AG variant differs only in test conditions for h_FE (measured at I_C = 2.0 A vs. 1.5 A for BD676) and does not alter electrical connectivity or footprint-making BD676AG a direct layout-compatible upgrade where higher-current gain validation is needed.

What is the thermal resistance from junction to case for BD676?

The BD676 has a thermal resistance from junction to case (R_JC) of 3.13 °C/W, as specified in the onsemi BD676/D datasheet. This value is critical for calculating junction temperature rise (T_J = T_C + P_D × R_JC) and must be used with actual measured case temperature and power dissipation-not ambient-to ensure safe operation within the −55 to +150 °C junction range.

Does BD676 support complementary amplifier designs?

Yes, BD676 is explicitly designed for complementary amplifier applications and is listed in the onsemi datasheet as complementary to NPN devices BD675, BD675A, BD677, BD677A, BD679, BD679A, and BD681. Its PNP polarity, matched power rating, and SOA curves align with those NPN counterparts to enable symmetrical push-pull output stages in Class AB and B amplifiers.

What is the DC current gain (h_FE) specification for BD676?

The BD676 guarantees a minimum DC current gain (h_FE) of 750 when tested at I_C = 1.5 Adc and V_CE = 3.0 Vdc, per the onsemi BD676/D datasheet. This high gain enables low base drive current (as low as ~2 mA typical for 1.5 A collector current), reducing driver-stage complexity and power loss in amplifier and switching applications.

BD676 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:: 2.5V @ 30mA, 1.5A

Current - Collector Cutoff (Max):: 500µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 750 @ 1.5A, 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

BD676 FAQ

1.How can I place an order for BD676 through Aetrix?

Please submit a Request for Quotation (RFQ) for BD676 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 BD676 reliable?

The price and inventory of BD676 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD676 is usually 5 days.

3.What payment methods are accepted for BD676?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD676 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD676?

BD676 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD676 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 BD676?

For technical support, including BD676 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD676 requirements.

6.How does Aetrix verify that BD676 is sourced from the original manufacturer or authorized distributors?

All BD676 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 BD676 meets industry standards.

7.What is the process for return or replacement of BD676?

All BD676 units undergo pre-shipment inspection (PSI). If there is an issue with BD676, 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 BD676 part is unused and in its original packaging.

Return procedure for BD676:

1.Submit a request within 90 days.

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

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