2SB647-B-AP Equivalent & Substitute Parts

Part Overview

The 2SB647-B-AP is a PNP bipolar junction transistor manufactured by Micro Commercial Co, designed for general-purpose switching and amplification applications. This component features an 80 V collector-emitter breakdown voltage rating and 1 A maximum collector current capability, housed in a TO-92MOD through-hole package. The device operates across a temperature range of -55°C to 150°C and dissipates up to 900 mW.

The 2SB647-B-AP is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production or repair requirements for legacy systems utilizing this transistor.

Substiute Parts

2SB647-B-AP

Micro Commercial CoIn Stock: 7702SB647-B-AP Datasheet

Current PartRFQ

BC640TA

onsemiIn Stock: 3513BC640TA Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2SB647-B-AP is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

• Transistor polarity must be PNP
• Maximum collector current (Ic) must equal or exceed 1 A
• Collector-emitter breakdown voltage (VCEO) must equal or exceed 80 V
• Maximum power dissipation must support the application requirements
• Operating temperature range must encompass the intended operating environment

Mechanical Compatibility Criteria:

• Package type must be TO-92-3 (through-hole configuration)
• Lead formation and pin assignment must be compatible with existing PCB layouts

The BC640TA, manufactured by onsemi, meets these substitution criteria. Both devices share identical maximum collector current (1 A) and collector-emitter breakdown voltage (80 V) ratings, operate within compatible temperature ranges, and utilize the same TO-92-3 through-hole package configuration.

Parameter Comparison

Engineering Selection Recommendations

The BC640TA is a direct electrical and mechanical substitute for the 2SB647-B-AP in applications requiring PNP transistor functionality with 80 V breakdown voltage and 1 A collector current ratings.

Compliance and Status Considerations:

The 2SB647-B-AP is obsolete, whereas the BC640TA maintains active product status with established supply chain availability. Both devices are ROHS3 compliant, ensuring regulatory alignment for new designs and legacy system support.

Performance Characteristics:

The BC640TA provides superior performance in several parameters: maximum power dissipation increases from 900 mW to 1000 mW, and collector cutoff current reduces from 10 µA to 100 nA, indicating lower leakage characteristics. The BC640TA exhibits lower saturation voltage (500 mV versus 1 V at specified conditions), which may reduce power dissipation in switching applications.

The 2SB647-B-AP maintains a higher transition frequency (140 MHz versus 100 MHz), which may be relevant for high-frequency switching applications. The 2SB647-B-AP also specifies higher minimum DC current gain (60 versus 40 at 150 mA, 5V and 2V respectively).

Selection Basis:

For new designs or systems requiring active component support, the BC640TA is the appropriate selection. For legacy system maintenance where the 2SB647-B-AP remains available, either device satisfies the electrical and mechanical requirements. Component selection should be based on application-specific performance requirements, supply availability, and cost considerations.

Frequently Asked Questions (FAQ)

Q: Can the BC640TA directly replace the 2SB647-B-AP in existing circuits?

A: Yes. Both devices are PNP transistors with identical maximum collector current (1 A) and collector-emitter breakdown voltage (80 V) ratings. The TO-92-3 package configuration is identical, enabling direct PCB-level substitution without layout modifications. Verify that application-specific performance requirements (saturation voltage, transition frequency, current gain) are satisfied by the BC640TA's specifications.

Q: What are the key differences between these two transistors?

A: The primary differences are: (1) Product status—2SB647-B-AP is obsolete while BC640TA is active; (2) Maximum power dissipation—BC640TA rated at 1000 mW versus 900 mW; (3) Saturation voltage—BC640TA exhibits 500 mV versus 1 V at specified bias conditions; (4) Transition frequency—2SB647-B-AP operates at 140 MHz versus 100 MHz for BC640TA; (5) DC current gain—2SB647-B-AP specifies minimum 60 versus 40 for BC640TA at 150 mA collector current.

Q: Are there package compatibility concerns?

A: No. Both devices utilize the TO-92-3 through-hole package with formed leads. Pin assignments and mechanical dimensions are compatible, permitting direct substitution without PCB redesign.

Q: Which device should be selected for new designs?

A: The BC640TA is the appropriate selection for new designs. It maintains active product status, ensuring long-term supply chain availability and manufacturer support. The 2SB647-B-AP, being obsolete, presents supply risk and limited technical support.

Q: Are both devices RoHS compliant?

A: Yes. Both the 2SB647-B-AP and BC640TA are ROHS3 compliant, meeting environmental and regulatory requirements for electronic component manufacturing and use.

Q: How do the saturation voltage differences affect circuit performance?

A: The BC640TA's lower saturation voltage (500 mV versus 1 V) results in reduced voltage drop across the transistor during saturation. In switching applications, this reduces power dissipation and heat generation. In amplification circuits, this may affect biasing and gain characteristics. Circuit analysis is required to determine if this difference impacts application performance.

Q: What is the significance of the transition frequency difference?

A: The 2SB647-B-AP's higher transition frequency (140 MHz versus 100 MHz) indicates faster switching capability. For applications operating below 100 MHz, both devices are suitable. For high-frequency switching applications approaching or exceeding 100 MHz, the 2SB647-B-AP may provide superior performance. Application frequency requirements should guide device selection.