BC638 Equivalent & Substitute Parts

Part Overview

The BC638 is a PNP bipolar junction transistor manufactured by onsemi, rated for 60 V collector-emitter breakdown voltage and 500 mA maximum collector current. The device is packaged in a TO-92 through-hole configuration and is suitable for general-purpose switching and amplification applications requiring moderate power dissipation up to 625 mW.

The BC638 is classified as obsolete. Locating equivalent substitute parts is necessary to support ongoing maintenance, repair, and new design requirements where this transistor type is specified or functionally required.

Substiute Parts

BC638

onsemiIn Stock: 10433BC638 Datasheet

Current PartRFQ

PN2907A PBFREE

Central Semiconductor CorpIn Stock: 11246PN2907A PBFREE Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the BC638 is determined by the following critical parameters:

Electrical Compatibility Requirements:

• Transistor type must be PNP
• Collector-emitter breakdown voltage must be equal to or greater than 60 V
• Maximum collector current must be equal to or greater than 500 mA
• Maximum power dissipation must be equal to or greater than 625 mW
• Operating temperature range must encompass the application requirements

Mechanical Compatibility Requirements:

• Mounting type must be through-hole
• Package must be TO-92 or equivalent footprint (TO-226-3, TO-92-3)

Functional Compatibility:

• Transition frequency should support the intended switching or amplification frequency
• DC current gain characteristics should be suitable for the circuit design

The PN2907A PBFREE meets all substitution criteria and provides enhanced electrical performance characteristics while maintaining mechanical compatibility.

Parameter Comparison

Engineering Selection Recommendations

PN2907A PBFREE as Primary Substitute:

The PN2907A PBFREE is a direct functional substitute for the BC638. Both devices share identical collector-emitter breakdown voltage (60 V) and maximum power dissipation (625 mW). The PN2907A PBFREE provides superior electrical performance with 600 mA maximum collector current (versus 500 mA), higher transition frequency (200 MHz versus 150 MHz), and an extended lower operating temperature limit (-65°C versus -55°C).

The PN2907A PBFREE is manufactured by Central Semiconductor Corp and maintains active product status, ensuring continued availability and supply chain reliability. The device is ROHS3 compliant, meeting modern environmental and regulatory requirements, whereas the BC638 is RoHS non-compliant.

Both devices are packaged identically in TO-92-3 through-hole configuration, providing direct mechanical compatibility without circuit board redesign or component footprint modification.

The PN2907A PBFREE is suitable for all applications where the BC638 was previously specified, provided that the circuit design accommodates the enhanced electrical characteristics.

Frequently Asked Questions (FAQ)

Q: Can the PN2907A PBFREE directly replace the BC638 in existing circuits?

A: Yes. Both devices are PNP transistors with identical 60 V collector-emitter breakdown voltage and 625 mW power dissipation. The PN2907A PBFREE provides equal or superior performance across all critical parameters. The TO-92-3 package footprint is identical, requiring no circuit board modifications.

Q: What are the key differences between the BC638 and PN2907A PBFREE?

A: The PN2907A PBFREE offers higher maximum collector current (600 mA versus 500 mA), higher transition frequency (200 MHz versus 150 MHz), lower collector cutoff current (10 nA versus 100 nA), and an extended lower operating temperature limit (-65°C versus -55°C). The PN2907A PBFREE is ROHS3 compliant and maintains active product status.

Q: Are there any circuit design considerations when substituting the BC638 with the PN2907A PBFREE?

A: The enhanced electrical characteristics of the PN2907A PBFREE are compatible with all BC638 applications. No circuit modifications are required. The higher transition frequency and improved current gain characteristics may provide improved performance in switching applications.

Q: What is the package compatibility between these devices?

A: Both the BC638 and PN2907A PBFREE use the TO-92-3 through-hole package. The physical footprint, pin configuration, and mounting method are identical. No component placement or board layout changes are necessary.

Q: Why is the BC638 classified as obsolete?

A: The BC638 is no longer in active production. The PN2907A PBFREE serves as the recommended substitute for new designs and replacement applications, offering improved performance and regulatory compliance.

Q: Does the PN2907A PBFREE meet current environmental and regulatory standards?

A: Yes. The PN2907A PBFREE is ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for electronic components in most jurisdictions.