BD676 Equivalent & Substitute Parts

Part Overview

The BD676 is a PNP Darlington bipolar junction transistor manufactured by onsemi, rated for 45 V collector-emitter breakdown voltage and 4 A maximum collector current in a TO-126 through-hole package. This component is classified as obsolete, making identification of suitable substitute parts necessary for ongoing design support and production continuity. The BD676 delivers 40 W maximum power dissipation and operates across a temperature range of -55°C to 150°C.

Substiute Parts

BD676

onsemiIn Stock: 2367BD676 Datasheet

Current PartRFQ

BD678

STMicroelectronicsIn Stock: 1259BD678 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the BD676 are identified based on electrical and mechanical compatibility within the PNP Darlington transistor category. The substitution logic is based on the following critical parameters:

Electrical Compatibility Criteria:

• Transistor Type: PNP - Darlington configuration
• Current - Collector (Ic) (Max): Equal or greater than 4 A
• Voltage - Collector Emitter Breakdown (Max): Equal to or greater than 45 V
• Vce Saturation (Max) @ Ib, Ic: 2.5V @ 30mA, 1.5A
• Current - Collector Cutoff (Max): 500µA or lower
• DC Current Gain (hFE) (Min) @ Ic, Vce: 750 @ 1.5A, 3V or greater
• Power - Max: Equal to or greater than 40 W

Mechanical Compatibility Criteria:

• Mounting Type: Through Hole
• Package / Case: TO-225AA or TO-126-3 compatible pinouts

Substitute parts must satisfy all electrical parameters at or above the BD676 specifications to ensure functional equivalence in existing circuit designs.

Parameter Comparison

Engineering Selection Recommendations

The BD678 manufactured by STMicroelectronics is a direct electrical and mechanical substitute for the obsolete BD676. Both components share identical collector current (4 A), saturation voltage characteristics, current gain specifications, and power dissipation ratings (40 W). The BD678 provides a higher collector-emitter breakdown voltage rating of 60 V compared to the BD676's 45 V, offering enhanced voltage margin in applications operating near the 45 V threshold.

The BD678 holds Active product status, ensuring continued availability and supply chain reliability. The BD678 is ROHS3 compliant, whereas the BD676 is RoHS non-compliant. This compliance difference is significant for applications subject to RoHS regulations. Both components utilize compatible through-hole mounting and TO-126-3 package configurations, enabling direct physical substitution in existing PCB layouts.

The BD678 specifies a maximum operating junction temperature of 150°C, while the BD676 specifies -55°C to 150°C. For applications requiring the full -55°C lower temperature range, thermal performance validation is necessary.

Frequently Asked Questions (FAQ)

Q: Can the BD678 replace the BD676 in existing designs?

A: The BD678 is electrically and mechanically compatible with the BD676. Both components share identical collector current (4 A), saturation voltage (2.5V @ 30mA, 1.5A), current gain (750 @ 1.5A, 3V), and power dissipation (40 W) specifications. The BD678 provides higher voltage rating (60 V vs. 45 V) and maintains through-hole TO-126-3 package compatibility. Direct substitution is supported for applications operating within the specified electrical parameters.

Q: What are the key differences between BD676 and BD678?

A: The primary differences are: (1) Collector-emitter breakdown voltage: BD678 rated at 60 V versus BD676 at 45 V; (2) Product status: BD678 is Active while BD676 is Obsolete; (3) RoHS compliance: BD678 is ROHS3 compliant while BD676 is non-compliant; (4) Manufacturer: BD678 is manufactured by STMicroelectronics while BD676 is manufactured by onsemi; (5) Operating temperature specification: BD678 specifies 150°C maximum while BD676 specifies -55°C to 150°C range.

Q: Are the packages physically identical?

A: Both the BD676 and BD678 utilize through-hole mounting with TO-225AA and TO-126-3 package designations. Physical pin configuration and PCB footprint compatibility are maintained, enabling direct board-level substitution without layout modifications.

Q: Does the higher voltage rating of the BD678 affect circuit operation?

A: The BD678's 60 V collector-emitter breakdown rating exceeds the BD676's 45 V specification. In applications designed for 45 V operation, the higher rating provides additional voltage margin without affecting normal circuit performance. All other electrical characteristics remain identical.

Q: What compliance considerations apply to substitution?

A: The BD678 is ROHS3 compliant, whereas the BD676 is RoHS non-compliant. Applications subject to RoHS regulations require the BD678. The BD678 is also REACH Unaffected, matching the BD676 status. Both components carry EAR99 ECCN classification.