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

onsemi BD677G

Name: BD677G
Brand: onsemi
SKU: BD677G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BD677G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BD677G.pdf

Description:: TRANS NPN DARL 60V 4A TO-126

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BD677G from onsemi is a plastic medium-power silicon NPN Darlington transistor rated for 60 V_CEO, 4.0 A collector current, and 40 W total device dissipation at T_C = 25°C, with DC current gain (h_FE) ≥ 750 at I_C = 1.5 A and V_CE = 3.0 V - used as output devices in complementary general-purpose amplifier applications.

For engineers reviewing the BD677G datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-225 package thermal resistance (R_JC = 3.13°C/W), V_CE(sat) ≤ 2.5 V at I_C = 1.5 A / I_B = 30 mA, and RoHS-compliant Pb-free construction.

Technical Context

The BD677G integrates two NPN transistors in monolithic Darlington configuration to achieve high DC current gain and low base drive requirements. It operates with V_CEO = 60 V, V_CBO = 60 V, and V_EBO = 5.0 V, supporting linear and switching applications where high β and moderate power handling are required.

Its safe operating area is defined by bonding wire limits, secondary breakdown, and thermal derating - power dissipation drops linearly above 25°C at 0.32 W/°C. The device is complementary to BD676, BD678, and BD680 series PNP Darlingtons for push-pull amplifier stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	60 Vdc - maximum collector-emitter voltage before breakdown under open-base conditions; defines usable voltage swing in amplifier or switch applications.
I_C	4.0 Adc - continuous collector current rating; sets upper limit for load-driving capability in motor drivers or audio outputs.
P_D @ T_C = 25°C	40 W - total device power dissipation at case temperature 25°C; requires heatsinking for sustained operation near rating.
h_FE	≥ 750 - DC current gain at I_C = 1.5 A, V_CE = 3.0 V; enables low base current drive for high-current loads.
V_CE(sat)	≤ 2.5 Vdc - saturation voltage at I_C = 1.5 A, I_B = 30 mA; determines conduction loss and heat generation in switching use.
R_JC	3.13 °C/W - junction-to-case thermal resistance; critical for calculating heatsink requirements when mounting to PCB or chassis.

Pinout & Package

BD677G uses the TO-225 package (Case 77-09, Style 1), with metal tab electrically connected to collector. Package dimensions: D = 10.6–11.1 mm, E = 7.4–7.8 mm, L = 14.5–16.63 mm, and 3-pin leaded configuration.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Main current return path; connects to ground or low-side load reference; not isolated from package tab.
2, 4	Collector	Main high-side current path; internally tied to metal tab; must be electrically isolated from heatsink unless referenced to same potential.
3	Base	Control input; requires current-limited drive (I_B ≤ 1.0 A) to avoid damage; typical drive ~30 mA for full saturation.

Key Features

Feature	Design Value
High DC current gain (h_FE ≥ 750)	Reduces required base drive current by >10× vs. single transistor, simplifying driver stage design in power amplifiers.
Monolithic Darlington construction	Ensures matched transistor characteristics and stable gain across temperature, eliminating discrete pairing variability.
Complementary PNP pairing (BD676/678/680)	Enables direct implementation of Class AB push-pull output stages without external bias network redesign.
Pb-free and RoHS-compliant	Meets global environmental compliance requirements for industrial and consumer electronics manufacturing.

Applications

Audio Power Amplifier Output Stage	DC Motor Driver (Small Actuators)
Use Scenario: Final output stage in 10–20 W audio amplifiers driving 4–8 Ω speakers. IC Role / Device Role / Timing Role: NPN Darlington output transistor delivering high-current, low-distortion signal swing. Use Value: High h_FE reduces driver complexity; 60 V rating supports ±25 V rails; TO-225 package allows bolt-on heatsinking.	Use Scenario: H-bridge or single-ended driver for 12–24 V brushed DC motors in robotics or HVAC actuators. IC Role / Device Role / Timing Role: High-current switching element controlling motor direction/speed via PWM or on/off control. Use Value: Low V_CE(sat) minimizes conduction loss; 4 A rating handles stall currents up to 3 A continuous.
Linear Voltage Regulator Pass Element	Relay/Solenoid Driver Interface
Use Scenario: Series pass transistor in adjustable linear regulators supplying 1–3 A at up to 50 V output. IC Role / Device Role / Timing Role: Current-amplifying pass element controlled by error amplifier feedback loop. Use Value: High β ensures stable regulation under load transients; 40 W dissipation supports 5–10 W thermal margin at 25°C ambient.	Use Scenario: Driving 12–24 V electromagnetic relays or solenoids requiring 100–500 mA coil current. IC Role / Device Role / Timing Role: Switching interface between microcontroller GPIO and inductive load. Use Value: Built-in Darlington gain eliminates need for pre-driver transistor; V_EBO = 5.0 V tolerates standard logic-level base drive.

Audio Power Amplifier Output Stage

DC Motor Driver (Small Actuators)

Use Scenario: Final output stage in 10–20 W audio amplifiers driving 4–8 Ω speakers.

IC Role / Device Role / Timing Role: NPN Darlington output transistor delivering high-current, low-distortion signal swing.

Use Value: High h_FE reduces driver complexity; 60 V rating supports ±25 V rails; TO-225 package allows bolt-on heatsinking.

Use Scenario: H-bridge or single-ended driver for 12–24 V brushed DC motors in robotics or HVAC actuators.

IC Role / Device Role / Timing Role: High-current switching element controlling motor direction/speed via PWM or on/off control.

Use Value: Low V_CE(sat) minimizes conduction loss; 4 A rating handles stall currents up to 3 A continuous.

Linear Voltage Regulator Pass Element

Relay/Solenoid Driver Interface

Use Scenario: Series pass transistor in adjustable linear regulators supplying 1–3 A at up to 50 V output.

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

Use Value: High β ensures stable regulation under load transients; 40 W dissipation supports 5–10 W thermal margin at 25°C ambient.

Use Scenario: Driving 12–24 V electromagnetic relays or solenoids requiring 100–500 mA coil current.

IC Role / Device Role / Timing Role: Switching interface between microcontroller GPIO and inductive load.

Use Value: Built-in Darlington gain eliminates need for pre-driver transistor; V_EBO = 5.0 V tolerates standard logic-level base drive.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJE801	Identical electrical specs per onsemi documentation; same V_CEO = 60 V, I_C = 4.0 A, h_FE ≥ 750, TO-225 package.	No functional difference; historically cross-referenced as direct functional match in legacy designs.	Select MJE801 if sourcing from distributors carrying legacy ON Semiconductor stock or legacy BOMs referencing that part number.
BD677AG	Same V_CEO, I_C, and h_FE but tested at I_C = 2.0 A (vs. 1.5 A for BD677G); V_CE(sat) ≤ 2.8 V at higher drive (I_B = 40 mA).	Slightly higher base drive requirement; better suited for applications needing guaranteed gain at heavier loads.	Choose BD677AG when operating consistently above 2 A collector current or when tighter V_CE(sat) spec at elevated I_C is required.

Compared with MJE801 and BD677AG, the BD677G offers identical core ratings but optimized test conditions for 1.5 A operation - making it ideal for cost-sensitive, thermally constrained designs where base drive efficiency and mid-range current performance are prioritized.

Availability

BD677G is available at Aetrix Electronics and suitable for audio power amplifiers, DC motor drivers, linear voltage regulator pass elements, and relay/solenoid interfaces requiring stable component supply and long-term industrial availability.

Supply support for BD677G 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 power management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BD677G belongs to onsemi's plastic medium-power Darlington transistor family, designed specifically for cost-effective, high-gain output stages in general-purpose linear and switching power applications.

FAQ

What is the maximum collector-emitter voltage rating for BD677G?

The BD677G has a maximum collector-emitter voltage (V_CEO) rating of 60 Vdc under open-base conditions. This value is confirmed in the Absolute Maximum Ratings table of the official onsemi datasheet (Rev. 16, November 2024). Exceeding this voltage risks avalanche breakdown and permanent device failure, even with limited current.

Is BD677G pin-compatible with BD677AG?

Yes, BD677G and BD677AG share identical TO-225 package pinout (Emitter–Collector–Base at pins 1–2/4–3), mechanical dimensions, and thermal characteristics. However, BD677AG is characterized at higher test currents (I_C = 2.0 A), resulting in slightly different V_CE(sat) and h_FE specifications - both remain drop-in replacements in most circuits.

Does BD677G require a heatsink in normal operation?

Yes - BD677G dissipates up to 40 W at T_C = 25°C, but its R_JC = 3.13°C/W means even modest power levels (e.g., 10 W) raise junction temperature significantly without heatsinking. For reliable operation above ~2 W continuous dissipation, a properly mounted heatsink is mandatory per Figure 1 derating curves.

What is the base-emitter on voltage (V_BE(on)) for BD677G?

The BD677G exhibits a base-emitter on voltage (V_BE(on)) of ≤ 2.5 Vdc at I_C = 1.5 A and V_CE = 3.0 Vdc, as specified in the Electrical Characteristics table. This reflects the dual-V_BE drop inherent to Darlington topology and must be accounted for in base drive circuit design.

Can BD677G replace BD675G in an existing design?

No - BD677G is not a direct replacement for BD675G due to differing voltage ratings: BD675G has V_CEO = 45 V, while BD677G is rated for 60 V. Substituting BD677G into a BD675G design may be safe if voltage stress remains below 45 V, but BD675G cannot safely replace BD677G in 60 V applications without risk of failure.

BD677G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN - Darlington

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

Voltage - Collector Emitter Breakdown (Max):: 60 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

BD677G FAQ

1.How can I place an order for BD677G through Aetrix?

Please submit a Request for Quotation (RFQ) for BD677G 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 BD677G reliable?

The price and inventory of BD677G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD677G is usually 5 days.

3.What payment methods are accepted for BD677G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD677G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD677G?

BD677G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD677G 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 BD677G?

For technical support, including BD677G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD677G requirements.

6.How does Aetrix verify that BD677G is sourced from the original manufacturer or authorized distributors?

All BD677G 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 BD677G meets industry standards.

7.What is the process for return or replacement of BD677G?

All BD677G units undergo pre-shipment inspection (PSI). If there is an issue with BD677G, 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 BD677G part is unused and in its original packaging.

Return procedure for BD677G:

1.Submit a request within 90 days.

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

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