2N2905 Equivalent & Substitute Parts

Part Overview

The 2N2905 is a PNP bipolar junction transistor manufactured by onsemi, rated for 40 V collector-emitter breakdown voltage and 600 mA maximum collector current in a through-hole TO-39 metal can package. This device is classified as obsolete, making equivalent and substitute parts necessary for new designs and production continuity. The 2N2905 has been widely used in analog switching and amplification circuits where PNP transistor functionality is required within the specified voltage and current ratings.

Substiute Parts

2N2905

onsemiIn Stock: 18832N2905 Datasheet

Current PartRFQ

SMBT3906E6327HTSA1

Infineon TechnologiesIn Stock: 35044SMBT3906E6327HTSA1 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2N2905 is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

• Transistor polarity must remain PNP
• Voltage rating (Vce breakdown) must equal or exceed 40 V
• Current rating (Ic max) must support the application requirement; the substitute SMBT3906E6327HTSA1 operates at 200 mA maximum, which is lower than the 2N2905's 600 mA rating
• DC current gain (hFE) must meet or exceed 100 at specified test conditions
• Power dissipation capability must be adequate for the intended circuit

Mechanical Compatibility Criteria:

• Package type differs between through-hole (TO-39) and surface-mount (SOT-23) options
• Pinout configuration must be verified for the specific application circuit

The SMBT3906E6327HTSA1 (Infineon Technologies) shares the same PNP polarity and 40 V voltage rating as the 2N2905. However, this substitute operates at a reduced maximum collector current of 200 mA compared to the 2N2905's 600 mA, and uses surface-mount packaging (SOT-23) instead of through-hole (TO-39). This substitute is suitable only for applications where collector current does not exceed 200 mA.

Parameter Comparison

Engineering Selection Recommendations

For Direct Electrical Substitution (High Current Applications): The 2N2905 is rated for 600 mA collector current. The SMBT3906E6327HTSA1 is rated for only 200 mA maximum collector current and is not suitable as a direct substitute in applications requiring collector currents above 200 mA. Selection of this substitute requires verification that circuit current demands do not exceed 200 mA.

For Packaging Considerations: The 2N2905 uses through-hole TO-39 packaging, while the SMBT3906E6327HTSA1 uses surface-mount SOT-23 packaging. Through-hole designs cannot directly accommodate surface-mount components without circuit board redesign and layout modifications.

For Compliance and Product Status: The 2N2905 is classified as obsolete and RoHS non-compliant. The SMBT3906E6327HTSA1 is classified as Last Time Buy and ROHS3 compliant, making it suitable for new designs requiring regulatory compliance. Both devices maintain REACH Unaffected status.

For New Design Implementation: Applications requiring PNP transistor functionality at 40 V with collector currents not exceeding 200 mA may use the SMBT3906E6327HTSA1 with appropriate circuit board modifications to accommodate surface-mount packaging. Applications requiring higher collector currents must identify alternative PNP transistors rated for 600 mA or greater at 40 V breakdown voltage.

Frequently Asked Questions (FAQ)

Q: Can the SMBT3906E6327HTSA1 directly replace the 2N2905 in existing through-hole circuit boards?

A: No. The SMBT3906E6327HTSA1 uses surface-mount SOT-23 packaging while the 2N2905 uses through-hole TO-39 packaging. Direct board-level substitution is not possible without circuit board redesign and component placement modifications.

Q: What is the primary electrical limitation of using SMBT3906E6327HTSA1 as a substitute?

A: The SMBT3906E6327HTSA1 is rated for a maximum collector current of 200 mA, compared to the 2N2905's 600 mA rating. Applications requiring collector currents above 200 mA cannot use this substitute.

Q: Are the voltage ratings compatible between the 2N2905 and SMBT3906E6327HTSA1?

A: Yes. Both devices are rated for 40 V maximum collector-emitter breakdown voltage, making them electrically compatible in terms of voltage specifications.

Q: Does the SMBT3906E6327HTSA1 meet modern regulatory compliance requirements?

A: Yes. The SMBT3906E6327HTSA1 is ROHS3 compliant, whereas the 2N2905 is RoHS non-compliant. For new designs requiring regulatory compliance, the SMBT3906E6327HTSA1 is the appropriate choice within the specified current limitations.

Q: What is the DC current gain specification difference between these devices?

A: Both devices specify a minimum DC current gain (hFE) of 100, but at different test conditions. The 2N2905 specifies hFE at 150 mA collector current and 10 V Vce, while the SMBT3906E6327HTSA1 specifies hFE at 10 mA collector current and 1 V Vce. Gain performance at specific operating points must be verified against individual device datasheets.

Q: Is the 2N2905 still available for procurement?

A: The 2N2905 is classified as obsolete. Existing inventory may be available through component distributors, but long-term availability is not guaranteed. New designs should incorporate currently available alternatives.