KSP45TA Equivalent & Substitute Parts

Part Overview

The KSP45TA is an NPN bipolar junction transistor manufactured by onsemi, rated for 350 V collector-emitter breakdown voltage and 300 mA maximum collector current in a TO-92-3 through-hole package. This device is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design requirements and production continuity. Substitute parts must maintain functional compatibility within the specified electrical and mechanical parameters while accommodating the transition from obsolete to active product status.

Substiute Parts

KSP45TA

onsemiIn Stock: 3349KSP45TA Datasheet

Current PartRFQ

KSP44TF

onsemiIn Stock: 105401KSP44TF Datasheet

DirectRFQ

ZTX457STZ

Diodes IncorporatedIn Stock: 10121ZTX457STZ Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the KSP45TA are identified based on the following electrical and mechanical compatibility criteria:

Primary Substitution Criteria:

• Transistor Type: NPN configuration
• Mounting Type: Through Hole
• Package Compatibility: TO-92-3 or TO-92 compatible form factor
• Voltage Rating: Collector-emitter breakdown voltage equal to or greater than 350 V
• Current Rating: Collector current capacity equal to or greater than 300 mA
• Power Dissipation: Maximum power rating equal to or greater than 625 mW
• DC Current Gain: Minimum hFE of 50 or greater at specified test conditions

Substitute Classification:

Direct Substitute (KSP44TF): Maintains identical electrical performance envelope with enhanced voltage rating (400 V vs. 350 V), identical current and power ratings, and identical DC current gain specifications. Same manufacturer (onsemi) with active product status. Identical package and mounting configuration.

Similar Substitute (ZTX457STZ): Provides enhanced current capacity (500 mA vs. 300 mA) and power dissipation (1 W vs. 625 mW) with lower voltage rating (300 V vs. 350 V). Manufactured by Diodes Incorporated with active product status. Package is E-Line (TO-92 compatible) with identical through-hole mounting. Includes transition frequency specification (75 MHz) not present in KSP45TA.

Parameter Comparison

Engineering Selection Recommendations

KSP44TF Selection Criteria:

The KSP44TF is the primary direct substitute for the KSP45TA. This part maintains identical electrical specifications for collector current (300 mA), power dissipation (625 mW), and DC current gain (50 @ 10mA, 10V). The KSP44TF provides a higher voltage rating (400 V vs. 350 V), which ensures compatibility in applications operating at or below 350 V. Both parts are manufactured by onsemi with identical TO-92-3 packaging and through-hole mounting. The KSP44TF holds active product status, ensuring long-term availability and supply chain continuity. RoHS3 compliance and REACH unaffected status are maintained. This part is suitable for direct replacement in existing designs without circuit modification.

ZTX457STZ Selection Criteria:

The ZTX457STZ is a similar substitute offering enhanced performance characteristics in specific parameters. This part provides increased collector current capacity (500 mA vs. 300 mA) and higher power dissipation (1 W vs. 625 mW), accommodating applications requiring higher current handling. The ZTX457STZ operates at a lower voltage rating (300 V vs. 350 V), restricting its use to applications operating below 300 V. The E-Line package is physically compatible with TO-92 form factors and maintains through-hole mounting. The ZTX457STZ includes transition frequency specification (75 MHz), enabling use in higher-frequency switching applications. This part is manufactured by Diodes Incorporated with active product status. RoHS3 compliance and REACH unaffected status are maintained. Selection of this part requires circuit evaluation to confirm voltage rating adequacy and to assess performance benefits from enhanced current capacity.

Compliance and Regulatory Considerations:

Both substitute parts maintain RoHS3 compliance and REACH unaffected status, ensuring regulatory alignment with the original KSP45TA. Both parts are classified under ECCN EAR99, maintaining export control consistency. Moisture sensitivity level (MSL) for KSP44TF is not applicable, while ZTX457STZ maintains MSL 1 (Unlimited) classification identical to the original part.

Frequently Asked Questions (FAQ)

Q: Can the KSP44TF be used as a direct replacement for the KSP45TA in all applications?

A: The KSP44TF maintains identical electrical performance specifications for collector current (300 mA), power dissipation (625 mW), and DC current gain (50 @ 10mA, 10V). The higher voltage rating (400 V vs. 350 V) ensures compatibility in applications operating at or below 350 V. Identical TO-92-3 packaging and through-hole mounting enable direct physical substitution. The KSP44TF is suitable for direct replacement without circuit modification.

Q: What are the key differences between the KSP44TF and ZTX457STZ?

A: The KSP44TF is a direct onsemi substitute with identical current and power ratings but higher voltage (400 V). The ZTX457STZ is a Diodes Incorporated part with enhanced current capacity (500 mA vs. 300 mA) and power dissipation (1 W vs. 625 mW), but lower voltage rating (300 V vs. 350 V). The ZTX457STZ includes transition frequency specification (75 MHz) and lower saturation voltage (300mV vs. 750mV), making it suitable for higher-frequency applications with lower current requirements.

Q: Is the ZTX457STZ package compatible with the KSP45TA?

A: The ZTX457STZ uses an E-Line package specified as TO-92 compatible with identical through-hole mounting. Physical compatibility exists for PCB mounting; however, lead geometry and spacing may differ slightly. Verification of lead dimensions and PCB hole alignment is required before implementation.

Q: What is the voltage rating limitation when using the ZTX457STZ?

A: The ZTX457STZ has a maximum collector-emitter breakdown voltage of 300 V, compared to 350 V for the KSP45TA. This part is restricted to applications operating at or below 300 V. Applications requiring operation above 300 V must use the KSP44TF or retain the original KSP45TA if available inventory permits.

Q: Are both substitute parts RoHS3 compliant?

A: Both the KSP44TF and ZTX457STZ are RoHS3 compliant and REACH unaffected, maintaining regulatory alignment with the original KSP45TA. Both parts are classified under ECCN EAR99 for export control purposes.

Q: What is the operating temperature range for each substitute part?

A: The KSP45TA and KSP44TF both specify a maximum junction temperature of 150°C. The ZTX457STZ extends the maximum junction temperature to 200°C, providing enhanced thermal performance for high-temperature applications.

Q: How do the saturation voltage characteristics compare between these parts?

A: The KSP45TA and KSP44TF both specify 750mV saturation voltage at 5mA base current and 50mA collector current. The ZTX457STZ specifies 300mV saturation voltage at 10mA base current and 100mA collector current, indicating superior saturation performance at higher current levels. This lower saturation voltage reduces power dissipation in saturated switching applications.

Q: Which substitute part should be selected for new designs?

A: For applications requiring the original 350 V voltage rating and 300 mA current capacity, the KSP44TF is the recommended substitute, offering identical electrical performance with active product status and long-term availability. For applications operating below 300 V with higher current requirements or higher-frequency operation, the ZTX457STZ provides enhanced performance characteristics. Circuit evaluation is required to confirm voltage and current adequacy for each application.