MPSA42-AP Equivalent & Substitute Parts

Part Overview

The MPSA42-AP is an NPN bipolar junction transistor manufactured by Micro Commercial Co, designed for general-purpose switching and amplification applications. This device features a 300 V collector-emitter breakdown voltage rating, 300 mA maximum collector current, and 625 mW power dissipation capability in a Through Hole TO-92 package. The MPSA42-AP is classified as obsolete, making identification of functionally equivalent substitute components necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Current - Collector (Ic) Max	300	mA
Voltage - Collector Emitter Breakdown (Max)	300	V
Vce Saturation (Max)	500	mV @ 2mA, 20mA
Current - Collector Cutoff (Max)	250	nA
DC Current Gain (hFE) Min	80	@ 10mA, 10V
Power - Max	625	mW
Frequency - Transition	50	MHz
Operating Temperature Range	-55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-92-3	—

Substitute Part Grouping Explanation

Substitution of the MPSA42-AP is determined by electrical parameter compatibility within the following criteria:

Primary Substitution Parameters:

Transistor Type: NPN (required match)
Current - Collector (Ic) Max: 300 mA minimum requirement
Voltage - Collector Emitter Breakdown: 300 V minimum requirement
Mounting Type: Through Hole (required match)
Package Compatibility: TO-92 or TO-92 compatible form factor

Secondary Compatibility Parameters:

DC Current Gain (hFE): Minimum 80 at specified test conditions
Frequency - Transition: 50 MHz minimum
Operating Temperature Range: Must encompass or exceed -55°C to 150°C
Power Dissipation: 625 mW minimum capability

The ZTX458STZ qualifies as a substitute because it meets or exceeds all primary and secondary electrical parameters while maintaining Through Hole mounting and TO-92 compatible packaging.

Parameter Comparison

Parameter	MPSA42-AP	ZTX458STZ	Compatibility
Transistor Type	NPN	NPN	Match
Current - Collector (Ic) Max	300 mA	300 mA	Match
Voltage - Collector Emitter Breakdown (Max)	300 V	400 V	Substitute Exceeds
Vce Saturation (Max)	500 mV @ 2mA, 20mA	500 mV @ 6mA, 50mA	Compatible
Current - Collector Cutoff (Max)	250 nA	100 nA	Substitute Superior
DC Current Gain (hFE) Min	80 @ 10mA, 10V	100 @ 50mA, 10V	Substitute Exceeds
Power - Max	625 mW	1 W	Substitute Exceeds
Frequency - Transition	50 MHz	50 MHz	Match
Operating Temperature Range	-55 to 150 °C	-55 to 200 °C	Substitute Exceeds
Mounting Type	Through Hole	Through Hole	Match
Package / Case	TO-92-3	E-Line-3 (TO-92 compatible)	Compatible
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Match

Engineering Selection Recommendations

MPSA42-AP Status: Obsolete product with limited procurement availability (1004 pcs in stock).

ZTX458STZ Recommendation: The ZTX458STZ is an active product manufactured by Diodes Incorporated and qualifies as a direct electrical substitute for the MPSA42-AP. This substitute part demonstrates superior or equivalent performance across all critical electrical parameters:

Collector-emitter breakdown voltage is increased from 300 V to 400 V, providing enhanced voltage margin
Power dissipation capability is increased from 625 mW to 1 W
DC current gain is increased from 80 to 100 minimum
Collector cutoff current is reduced from 250 nA to 100 nA, indicating lower leakage
Operating temperature range is extended from 150°C to 200°C maximum junction temperature
Both devices maintain identical collector current (300 mA) and transition frequency (50 MHz) specifications

Compliance Status: Both the MPSA42-AP and ZTX458STZ are ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99. The ZTX458STZ is currently in active production status with 4200 pcs available in inventory, ensuring long-term procurement viability.

Package Consideration: The ZTX458STZ uses an E-Line-3 package with formed leads that is mechanically and electrically compatible with TO-92 footprints. Pin configuration and lead spacing conform to standard TO-92 through-hole mounting requirements.

Frequently Asked Questions (FAQ)

Q: Can the ZTX458STZ be used as a direct replacement for the MPSA42-AP in existing designs?

A: Yes. The ZTX458STZ meets all electrical parameter requirements of the MPSA42-AP and maintains compatible Through Hole packaging. The E-Line package is mechanically compatible with TO-92 PCB footprints. No circuit modifications are required.

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

A: The ZTX458STZ provides superior performance in four areas: (1) Collector-emitter breakdown voltage increased to 400 V versus 300 V, (2) Power dissipation increased to 1 W versus 625 mW, (3) DC current gain increased to 100 minimum versus 80 minimum, and (4) Operating temperature range extended to 200°C versus 150°C. Collector current, transition frequency, and saturation voltage remain equivalent.

Q: Are there any package compatibility concerns?

A: No. The ZTX458STZ E-Line-3 package with formed leads is designed for TO-92 footprint compatibility. Pin spacing, lead diameter, and through-hole mounting requirements are standard across both devices.

Q: Why is the MPSA42-AP classified as obsolete?

A: The MPSA42-AP is no longer in active production. The ZTX458STZ represents the current active equivalent in the market, offering improved electrical specifications and assured long-term availability.

Q: What compliance certifications apply to both parts?

A: Both the MPSA42-AP and ZTX458STZ are ROHS3 compliant with Moisture Sensitivity Level 1 (unlimited shelf life). Both are REACH unaffected and classified under ECCN EAR99 for export control purposes.

Q: Can the ZTX458STZ be used in applications requiring the full 300 V rating of the MPSA42-AP?

A: Yes. The ZTX458STZ exceeds the 300 V requirement with a 400 V collector-emitter breakdown rating, providing additional voltage margin and enhanced reliability in high-voltage switching applications.

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