ZTX458 Equivalent & Substitute Parts

Part Overview

The ZTX458 is an NPN bipolar junction transistor manufactured by Diodes Incorporated, designed for general-purpose switching and amplification applications. This through-hole component operates at 400 V collector-emitter breakdown voltage with a maximum collector current of 300 mA and 1 W power dissipation capability. The device is currently in active production status with robust inventory availability. Substitute parts are identified to provide design flexibility, supply chain alternatives, and equivalent functional performance for applications where the ZTX458 may be unavailable or where alternative sourcing is required.

Substiute Parts

ZTX458

Diodes IncorporatedIn Stock: 5190ZTX458 Datasheet

Current PartRFQ

KSP44BU

onsemiIn Stock: 35429KSP44BU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the ZTX458 is determined by strict equivalence across the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

• Transistor type must be NPN
• Voltage - Collector Emitter Breakdown rating must be 400 V or greater
• Current - Collector (Ic) maximum rating must be 300 mA or greater
• Mounting type must be through-hole configuration
• Package compatibility must support E-Line or TO-92 form factors

Compliance Criteria:

• RoHS3 compliance required
• REACH Unaffected status required
• Active product status preferred

The KSP44BU from onsemi meets all electrical and mechanical substitution criteria, providing equivalent voltage and current ratings within a compatible through-hole package configuration.

Parameter Comparison

Engineering Selection Recommendations

ZTX458 (Primary Selection): The ZTX458 is recommended as the primary component choice where available. This device offers 1 W maximum power dissipation, higher DC current gain (hFE minimum of 100), and lower collector cutoff current (100 nA), providing superior performance margins in switching and amplification circuits. Active production status and robust inventory levels support reliable procurement.

KSP44BU (Substitute Selection): The KSP44BU serves as a qualified substitute when ZTX458 availability is constrained. Both devices maintain identical voltage and current ratings (400 V, 300 mA) and are housed in compatible through-hole packages. The KSP44BU operates within the same electrical envelope for applications where the reduced power rating (625 mW versus 1 W) and lower DC current gain do not present design constraints. Both components maintain ROHS3 compliance and REACH Unaffected status, ensuring regulatory equivalence.

Frequently Asked Questions (FAQ)

Q: Can the KSP44BU directly replace the ZTX458 in all applications?

A: The KSP44BU is electrically equivalent for voltage and current ratings (400 V, 300 mA). However, the reduced maximum power dissipation (625 mW versus 1 W) and lower DC current gain (50 versus 100 minimum) require circuit-level verification. Applications operating near the 1 W power limit or requiring higher current gain may require design adjustment.

Q: Are the packages physically compatible?

A: Both devices use through-hole TO-92 compatible packaging. The ZTX458 uses E-Line-3 (TO-92 compatible) and the KSP44BU uses TO-92-3 (TO-226AA). These packages are mechanically interchangeable in standard through-hole PCB layouts.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the ZTX458 and KSP44BU are ROHS3 compliant and REACH Unaffected, meeting equivalent regulatory requirements for commercial and industrial applications.

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

A: The primary differences are maximum power dissipation (1 W versus 625 mW), DC current gain at specified conditions (100 versus 50 minimum), and collector cutoff current (100 nA versus 500 nA). Vce saturation characteristics also differ slightly at specified bias conditions.

Q: Which part should be selected for new designs?

A: The ZTX458 is the recommended choice for new designs due to superior power handling and current gain characteristics. The KSP44BU should be considered only when ZTX458 supply constraints exist or when application requirements align with its reduced power rating.