BD676G PNP Darlington Transistor Equivalent & Substitute Parts

Part Overview

The BD676G 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 device is classified as obsolete, necessitating identification of functionally equivalent substitute components for ongoing design support and production requirements. Substitute parts must maintain electrical compatibility across critical parameters including collector current rating, power dissipation, DC current gain, and thermal operating range while accommodating package variations where applicable.

Substiute Parts

BD676G

onsemiIn Stock: 1969BD676G Datasheet

Current PartRFQ

MJE703G

onsemiIn Stock: 2418MJE703G Datasheet

SimilarRFQ

BD678

STMicroelectronicsIn Stock: 1259BD678 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the BD676G are selected based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

Mandatory Compatibility Criteria:

• Transistor Type: PNP - Darlington configuration
• Current Rating: Minimum 4 A collector current capacity
• Power Dissipation: Minimum 40 W rating
• DC Current Gain: Minimum 750 hFE at specified test conditions
• Mounting Type: Through Hole
• Operating Temperature Range: Support for -55°C to 150°C junction temperature

Allowable Variations:

• Collector-Emitter Breakdown Voltage: Equal to or greater than 45 V (higher voltage ratings provide expanded application range)
• Package Designation: TO-126-3 or equivalent through-hole packages (SOT-32-3 acceptable with mechanical verification)
• Saturation Voltage: Minor variations acceptable within design margin
• Cutoff Current: Variations within specified ranges

Substitute parts MJE703G and BD678 satisfy these criteria with documented electrical equivalence and thermal compatibility.

Parameter Comparison

Engineering Selection Recommendations

MJE703G (onsemi): MJE703G provides direct electrical substitution with enhanced voltage rating (80 V versus 45 V). This higher breakdown voltage accommodates applications with transient overvoltage conditions while maintaining identical current and power specifications. Both BD676G and MJE703G share onsemi manufacturing heritage and identical thermal operating range. MJE703G is classified as obsolete; however, inventory availability (2400 pcs) exceeds BD676G stock levels. This part is suitable for applications where voltage margin enhancement is beneficial and where TO-126 package compatibility is required.

BD678 (STMicroelectronics): BD678 delivers electrical equivalence with intermediate voltage rating (60 V) and active product status, indicating ongoing manufacturing support and long-term availability. Saturation voltage and cutoff current specifications are identical to BD676G. The primary distinction is package designation (SOT-32-3 versus TO-126), which requires mechanical verification for PCB footprint compatibility. BD678 is the preferred substitute for new designs and production continuity due to active status and multi-source availability through STMicroelectronics.

Compliance Considerations: All three devices maintain ROHS3 compliance and REACH unaffected status, satisfying regulatory requirements for industrial and commercial applications. Moisture sensitivity level (MSL) is rated as 1 (Unlimited) for BD676G and BD678, indicating no special handling requirements during storage or assembly.

Frequently Asked Questions (FAQ)

Q: Can MJE703G replace BD676G in existing designs without circuit modification?

A: MJE703G provides direct functional substitution. The higher collector-emitter breakdown voltage (80 V versus 45 V) does not require circuit modification and provides additional design margin. Electrical characteristics including current gain, saturation voltage, and thermal range are compatible. Pin configuration and TO-126 package dimensions are identical.

Q: What is the primary difference between BD678 and BD676G?

A: BD678 differs in two aspects: (1) Collector-emitter breakdown voltage is 60 V versus 45 V, and (2) Supplier device package is SOT-32-3 versus TO-126. Electrical performance parameters including current rating, power dissipation, and DC current gain are equivalent. Package designation requires verification of PCB footprint compatibility before substitution.

Q: Why is BD678 recommended for new designs despite being from a different manufacturer?

A: BD678 holds active product status, indicating ongoing manufacturing support and long-term availability. BD676G and MJE703G are both classified as obsolete, creating supply chain risk for production continuity. STMicroelectronics maintains BD678 in active production, ensuring component availability for future procurement cycles.

Q: Are there thermal management differences between these three devices?

A: All three devices share identical maximum power dissipation (40 W) and operating temperature range (-55°C to 150°C junction temperature). Thermal performance is equivalent across BD676G, MJE703G, and BD678. Thermal management strategy and heatsink requirements remain unchanged during substitution.

Q: Can BD676G be substituted with a lower voltage-rated device?

A: No. Substitute parts must maintain collector-emitter breakdown voltage equal to or greater than the original specification (45 V minimum). MJE703G (80 V) and BD678 (60 V) both exceed this requirement. Lower voltage alternatives do not satisfy electrical compatibility criteria.

Q: What packaging considerations apply when substituting BD678 for BD676G?

A: BD678 uses SOT-32-3 package designation while BD676G uses TO-126. Both are through-hole packages with TO-225AA case family designation. Physical dimensions and pin spacing require verification against PCB layout before implementation. Mechanical compatibility must be confirmed through package datasheet comparison.

Q: Are there inventory or lead-time advantages to selecting one substitute over another?

A: MJE703G shows higher inventory availability (2400 pcs) compared to BD676G (1900 pcs). BD678 is active status, providing long-term supply assurance. For immediate procurement, MJE703G offers stock availability. For production continuity, BD678 provides manufacturing support and future availability.

Q: Do all three devices meet the same regulatory compliance standards?

A: Yes. BD676G, MJE703G, and BD678 are all ROHS3 compliant and REACH unaffected. Moisture sensitivity level is 1 (Unlimited) for BD676G and BD678, indicating no special handling requirements. All devices satisfy industrial and commercial regulatory requirements.