MPSA42 Equivalent & Substitute Parts

Part Overview

The MPSA42 is an NPN bipolar junction transistor manufactured by Diotec Semiconductor, designed for general-purpose switching and amplification applications. This through-hole component operates at 300 V collector-emitter breakdown voltage with a maximum collector current of 500 mA and power dissipation of 625 mW. The part is currently in active production status with substantial inventory availability. Substitute parts are identified to provide alternative sourcing options when the primary manufacturer part is unavailable or when supply chain optimization is required.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Collector Current (Maximum)	500	mA
Collector-Emitter Breakdown Voltage	300	V
Power Dissipation (Maximum)	625	mW
Transition Frequency	50	MHz
DC Current Gain (hFE Minimum)	40	@ 30mA, 10V
Vce Saturation (Maximum)	500	mV @ 2mA, 20mA
Collector Cutoff Current (Maximum)	100	nA
Operating Temperature Range	-55 to 150	°C
Package Type	TO-92	—
Mounting Type	Through Hole	—

Substitute Part Grouping Explanation

Substitute parts for the MPSA42 are identified based on electrical and mechanical parameter equivalence. The substitution criteria are strictly limited to the following parameters:

Transistor type classification (NPN)
Maximum collector current rating (500 mA)
Collector-emitter breakdown voltage (300 V)
Maximum power dissipation (625 mW)
Transition frequency (50 MHz)
DC current gain specification (40 minimum @ 30mA, 10V)
Saturation voltage characteristics (500 mV @ 2mA, 20mA)
Collector cutoff current (100 nA maximum)
Package and mounting configuration (TO-92 through-hole)

Parts meeting all these electrical and mechanical specifications are classified as parametric equivalents and direct substitutes. The KSP42TA from onsemi satisfies all specified parameters and is therefore a valid substitute for the MPSA42.

Parameter Comparison

Parameter	MPSA42 (Diotec)	KSP42TA (onsemi)	Match
Transistor Type	NPN	NPN	Yes
Collector Current (Max)	500 mA	500 mA	Yes
Collector-Emitter Breakdown Voltage	300 V	300 V	Yes
Power Dissipation (Max)	625 mW	625 mW	Yes
Transition Frequency	50 MHz	50 MHz	Yes
DC Current Gain (hFE Min)	40 @ 30mA, 10V	40 @ 30mA, 10V	Yes
Vce Saturation (Max)	500 mV @ 2mA, 20mA	500 mV @ 2mA, 20mA	Yes
Collector Cutoff Current (Max)	100 nA	100 nA	Yes
Package Type	TO-92	TO-92-3	Yes
Mounting Type	Through Hole	Through Hole	Yes
Product Status	Active	Active	Yes

Engineering Selection Recommendations

Both the MPSA42 and KSP42TA are active production components with full electrical and mechanical parameter equivalence. Selection between these parts should be based on the following factors:

Compliance Status: The KSP42TA carries ROHS3 compliance certification and REACH unaffected status, providing documented regulatory compliance for applications subject to these requirements. The MPSA42 RoHS status is listed as not applicable.

Inventory and Supply: The KSP42TA maintains higher inventory levels (55,300 pieces) compared to the MPSA42 (27,010 pieces), which may influence lead time and availability for high-volume applications.

Manufacturer Considerations: Selection between Diotec Semiconductor and onsemi should be based on existing supply chain relationships, qualification requirements, and procurement policies specific to the application.

Both parts are electrically and mechanically interchangeable for applications requiring NPN transistors with the specified electrical characteristics and TO-92 package configuration.

Frequently Asked Questions (FAQ)

Q: Can the KSP42TA be used as a direct replacement for the MPSA42 in existing designs?

A: Yes. The KSP42TA meets all electrical specifications and mechanical requirements of the MPSA42. Both components share identical maximum ratings for collector current, breakdown voltage, power dissipation, transition frequency, and current gain characteristics. The TO-92 package configuration is identical, allowing direct pin-compatible substitution.

Q: What are the key electrical parameters that define substitution eligibility?

A: Substitution eligibility is determined by matching the following parameters: NPN transistor type, 500 mA maximum collector current, 300 V collector-emitter breakdown voltage, 625 mW maximum power dissipation, 50 MHz transition frequency, 40 minimum DC current gain at specified conditions, 500 mV saturation voltage, and 100 nA maximum collector cutoff current.

Q: Are there differences in operating temperature ranges between these parts?

A: The MPSA42 specifies an operating temperature range of -55°C to 150°C. The KSP42TA specifies a maximum operating temperature of 150°C. Both parts support the standard industrial temperature range. Applications requiring the full -55°C lower limit should verify KSP42TA specifications with the manufacturer.

Q: Do package differences affect mechanical compatibility?

A: Both parts use TO-92 package configuration with formed leads suitable for through-hole mounting. The MPSA42 is designated TO-226-3 (TO-92-3) and the KSP42TA is designated TO-92-3. These designations refer to the same physical package standard, ensuring mechanical compatibility in PCB layouts and socket applications.

Q: What compliance certifications should be considered for regulatory applications?

A: The KSP42TA carries ROHS3 compliance and REACH unaffected status. The MPSA42 does not specify these certifications. Applications subject to RoHS or REACH regulations should use the KSP42TA or verify MPSA42 compliance status with the manufacturer.

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