KSC2258AS Equivalent & Substitute Parts

Part Overview

The KSC2258AS is an NPN bipolar junction transistor manufactured by onsemi, rated for 300 V collector-emitter breakdown voltage and 100 mA maximum collector current. This device is packaged in a TO-126-3 through-hole configuration and is designed for general-purpose switching and amplification applications requiring moderate voltage and current ratings.

The KSC2258AS is classified as obsolete. Locating equivalent or substitute components is necessary to support ongoing maintenance, repair, and new design requirements where this part is specified or where inventory depletion necessitates alternative sourcing.

Substiute Parts

KSC2258AS

onsemiIn Stock: 732KSC2258AS Datasheet

Current PartRFQ

MJE340

NTE Electronics, IncIn Stock: 2035MJE340 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the KSC2258AS is determined by alignment of the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Transistor type must be NPN
• Voltage - Collector Emitter Breakdown rating must equal or exceed 300 V
• Current - Collector (Ic) maximum rating must equal or exceed 100 mA
• Power dissipation rating must equal or exceed 4 W
• Package / Case must be compatible with TO-126-3 footprint and through-hole mounting

Mechanical Compatibility Criteria:

• Mounting type must be Through Hole
• Package configuration must support direct or pin-compatible substitution

The MJE340 satisfies these substitution criteria. It is an NPN transistor with 300 V collector-emitter breakdown voltage, 500 mA maximum collector current (exceeding the 100 mA requirement), 20 W power rating (exceeding the 4 W requirement), and TO-126 through-hole packaging compatible with the original part's footprint.

Parameter Comparison

Engineering Selection Recommendations

The MJE340 is the identified substitute for the KSC2258AS based on electrical and mechanical parameter alignment.

Status Consideration: The KSC2258AS is obsolete, while the MJE340 is active. Selection of the MJE340 ensures continued component availability and supply chain continuity.

Compliance Consideration: The MJE340 is classified as RoHS non-compliant. Applications subject to RoHS requirements must evaluate compliance obligations before substitution.

Electrical Margin: The MJE340 provides higher current capacity (500 mA versus 100 mA) and higher power dissipation capability (20 W versus 4 W). These elevated ratings provide operational margin in applications where the KSC2258AS was previously specified.

Package Compatibility: Both devices use TO-126 through-hole packaging. Pin configuration and footprint compatibility must be verified against the specific application schematic and PCB layout.

Frequently Asked Questions (FAQ)

Q: Can the MJE340 be used as a direct replacement for the KSC2258AS?

A: The MJE340 meets the electrical and mechanical substitution criteria for the KSC2258AS. Both devices are NPN transistors with 300 V collector-emitter breakdown voltage, through-hole TO-126 packaging, and compatible pin configurations. Pin-for-pin substitution is supported. However, circuit design verification is required to confirm that the higher current and power ratings of the MJE340 do not introduce unintended operational changes.

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

A: The primary differences are maximum collector current (MJE340: 500 mA versus KSC2258AS: 100 mA), maximum power dissipation (MJE340: 20 W versus KSC2258AS: 4 W), and product status (MJE340: Active versus KSC2258AS: Obsolete). The DC current gain specifications differ slightly between the two devices at different operating points.

Q: Are there any compliance concerns with the MJE340?

A: The MJE340 is RoHS non-compliant. Applications operating under RoHS directives or equivalent environmental regulations must evaluate whether this substitution aligns with compliance requirements.

Q: Does the higher current rating of the MJE340 affect circuit operation?

A: The MJE340's higher current and power ratings do not inherently change circuit operation if the original circuit design operates within the KSC2258AS specifications. The MJE340 will function correctly in applications designed for the KSC2258AS. However, thermal management and circuit protection schemes should be reviewed to ensure they remain appropriate for the substitute device.

Q: Are the packages physically identical?

A: Both devices use TO-126 through-hole packaging. The KSC2258AS is specified as TO-126-3, and the MJE340 is specified as TO-126. These designations refer to the same physical package form factor with compatible pin spacing and mounting characteristics. Verification against the specific PCB layout is recommended.