MPSA44G Equivalent & Substitute Parts

Part Overview

The MPSA44G is an NPN bipolar junction transistor manufactured by onsemi, rated for 400 V collector-emitter breakdown voltage and 300 mA maximum collector current in a Through Hole TO-92 package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The MPSA44G delivers 625 mW maximum power dissipation and operates across a temperature range of -55°C to 150°C, serving applications requiring moderate voltage and current switching capabilities.

Substiute Parts

MPSA44G

onsemiIn Stock: 85282MPSA44G Datasheet

Current PartRFQ

KSP44BU

onsemiIn Stock: 35429KSP44BU Datasheet

DirectRFQ

ZTX458

Diodes IncorporatedIn Stock: 5190ZTX458 Datasheet

DirectRFQ

ZTX458STZ

Diodes IncorporatedIn Stock: 4272ZTX458STZ Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the MPSA44G is determined by matching the following critical electrical and mechanical parameters:

Electrical Matching Criteria:

• Transistor Type: NPN configuration
• Maximum Collector Current (Ic): 300 mA minimum
• Collector-Emitter Breakdown Voltage: 400 V minimum
• Maximum Power Dissipation: 625 mW minimum
• DC Current Gain (hFE): Sufficient for intended application bias conditions

Mechanical Matching Criteria:

• Mounting Type: Through Hole
• Package Compatibility: TO-92 or TO-92 compatible form factors

Substitute parts are grouped into two categories based on these parameters:

Direct Substitutes (Electrical and Mechanical Equivalence): Parts that match or exceed all key electrical parameters and maintain compatible Through Hole packaging.

Compatible Alternatives (Enhanced Performance): Parts that exceed baseline specifications in power rating, frequency response, or temperature range while maintaining electrical and mechanical compatibility.

Parameter Comparison

Engineering Selection Recommendations

KSP44BU (onsemi): The KSP44BU is an active product offering direct electrical equivalence to the MPSA44G with identical maximum ratings for collector current, breakdown voltage, and power dissipation. Both devices share the same DC current gain specification and saturation voltage characteristics. The KSP44BU maintains the TO-92-3 package form factor and is ROHS3 compliant, supporting modern supply chain requirements. This part is the primary recommendation for direct replacement in existing MPSA44G designs.

ZTX458 and ZTX458STZ (Diodes Incorporated): The ZTX458 and ZTX458STZ are active products from Diodes Incorporated that exceed MPSA44G specifications in several parameters: maximum power dissipation is increased to 1 W, transition frequency is specified at 50 MHz, and operating temperature range extends to 200°C. Both devices maintain the required 400 V breakdown voltage and 300 mA collector current ratings. The ZTX458 is supplied in Bulk packaging, while ZTX458STZ is supplied in Cut Tape (CT) with formed leads. Both are ROHS3 compliant. These parts are suitable for applications requiring enhanced thermal performance or higher-frequency operation within the same voltage and current envelope.

Packaging Considerations: The MPSA44G, KSP44BU, and ZTX458 series all employ Through Hole mounting with TO-92 compatible packages, ensuring mechanical interchangeability in PCB layouts. The ZTX458STZ variant includes formed leads, which may require lead-forming equipment during assembly.

Frequently Asked Questions (FAQ)

Q: Can KSP44BU directly replace MPSA44G in all applications?

A: Yes. The KSP44BU matches all critical electrical parameters of the MPSA44G: 300 mA maximum collector current, 400 V breakdown voltage, 625 mW power rating, and identical DC current gain and saturation voltage specifications. Both devices use the TO-92-3 package. The KSP44BU is an active product, addressing the obsolescence of the MPSA44G.

Q: What are the differences between ZTX458 and ZTX458STZ?

A: The ZTX458 and ZTX458STZ are electrically identical, both manufactured by Diodes Incorporated with the same electrical specifications. The primary difference is packaging: ZTX458 is supplied in Bulk, while ZTX458STZ is supplied in Cut Tape (CT) with formed leads. Both are E-Line-3 packages compatible with TO-92 footprints.

Q: Are ZTX458 devices suitable replacements for MPSA44G?

A: Yes, with performance enhancements. The ZTX458 series exceeds MPSA44G specifications in power dissipation (1 W vs. 625 mW), transition frequency (50 MHz specified), and operating temperature range (-55 to 200°C vs. -55 to 150°C). All critical voltage and current ratings are met or exceeded. These devices are suitable for applications requiring higher thermal headroom or faster switching.

Q: What is the significance of the E-Line package used by ZTX458?

A: The E-Line package is a Through Hole form factor compatible with TO-92 PCB footprints. This ensures mechanical interchangeability with MPSA44G and KSP44BU in existing designs without layout modifications.

Q: Are all substitute parts ROHS3 compliant?

A: KSP44BU, ZTX458, and ZTX458STZ are all ROHS3 compliant. The MPSA44G compliance status is not specified in the provided data.

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

A: For new designs, KSP44BU is recommended as the primary choice due to direct electrical equivalence, active product status, and ROHS3 compliance. ZTX458 or ZTX458STZ may be selected if enhanced thermal performance, higher frequency response, or extended temperature range is required by the application.

Q: Can these parts be used interchangeably in the same PCB assembly?

A: Yes. All substitute parts employ Through Hole mounting with TO-92 compatible packages, allowing direct PCB footprint compatibility. Lead-formed variants (ZTX458STZ) may require specific assembly equipment for lead forming.