STPSA42-AP Equivalent & Substitute Parts

Part Overview

The STPSA42-AP is an NPN bipolar junction transistor manufactured by STMicroelectronics, designed for general-purpose switching and amplification applications. This device operates at 300 V collector-emitter breakdown voltage with a maximum collector current of 500 mA and dissipates up to 625 mW. The STPSA42-AP is classified as obsolete, necessitating identification of active equivalent alternatives for new designs and ongoing production requirements. Substitute parts must maintain electrical and mechanical compatibility while offering active product status and continued availability.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Collector Current (Max)	500	mA
Collector-Emitter Breakdown Voltage (Max)	300	V
Vce Saturation (Max)	500	mV @ 2mA, 20mA
Collector Cutoff Current (Max)	100	nA
DC Current Gain (hFE Min)	40	@ 30mA, 10V
Power Dissipation (Max)	625	mW
Transition Frequency	50	MHz
Operating Temperature (Max)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the STPSA42-AP are identified based on strict parametric equivalence across all critical electrical and mechanical specifications. The substitution logic requires that alternative parts maintain identical or superior ratings in the following key parameters:

Collector current rating: 500 mA (maximum)
Collector-emitter breakdown voltage: 300 V (maximum)
Vce saturation characteristics: 500 mV @ 2mA, 20mA
Collector cutoff current: 100 nA (maximum)
DC current gain (hFE): minimum 40 @ 30mA, 10V
Power dissipation: 625 mW (maximum)
Transition frequency: 50 MHz (minimum)
Operating temperature: 150°C (maximum junction temperature)
Mounting type: Through Hole
Package configuration: TO-92-3 or TO-226-3 formed leads

The identified substitute parts KSP42TA and MPSA42 satisfy all parametric requirements and are available in active product status, ensuring long-term supply continuity and design reliability.

Parameter Comparison

Parameter	STPSA42-AP (STMicroelectronics)	KSP42TA (onsemi)	MPSA42 (Diotec Semiconductor)
Product Status	Obsolete	Active	Active
Transistor Type	NPN	NPN	NPN
Collector Current (Max)	500 mA	500 mA	500 mA
Collector-Emitter Breakdown Voltage (Max)	300 V	300 V	300 V
Vce Saturation (Max)	500 mV @ 2mA, 20mA	500 mV @ 2mA, 20mA	500 mV @ 2mA, 20mA
Collector Cutoff Current (Max)	100 nA	100 nA	100 nA
DC Current Gain (hFE Min)	40 @ 30mA, 10V	40 @ 30mA, 10V	40 @ 30mA, 10V
Power Dissipation (Max)	625 mW	625 mW	625 mW
Transition Frequency	50 MHz	50 MHz	50 MHz
Operating Temperature (Max)	150°C	150°C	150°C
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	TO-226-3, TO-92-3	TO-226-3, TO-92-3	TO-226-3, TO-92-3
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Not applicable
REACH Status	REACH Unaffected	REACH Unaffected	Vendor Undefined
ECCN	EAR99	EAR99	EAR99

Engineering Selection Recommendations

Both KSP42TA and MPSA42 are direct parametric equivalents to the obsolete STPSA42-AP and are suitable for substitution in applications requiring NPN transistors with 300 V breakdown voltage and 500 mA collector current ratings.

KSP42TA (onsemi) is recommended for applications requiring ROHS3 compliance certification. This part maintains active product status with confirmed inventory availability of 55,300 units. The KSP42TA carries REACH Unaffected status, ensuring regulatory compliance across international markets.

MPSA42 (Diotec Semiconductor) is recommended for applications where extended operating temperature range is beneficial. This part specifies an operating temperature range of −55°C to 150°C, compared to the 150°C maximum of the STPSA42-AP. The MPSA42 maintains active product status with inventory availability of 27,010 units. RoHS and REACH compliance status for this part is vendor-defined and should be confirmed with the supplier for applications requiring specific regulatory certifications.

Both substitute parts are supplied in TO-92-3 package configuration, ensuring mechanical and electrical compatibility with existing PCB layouts and socket designs. Selection between KSP42TA and MPSA42 should be based on specific regulatory requirements and operating temperature specifications of the target application.

Frequently Asked Questions (FAQ)

Q: Can KSP42TA and MPSA42 be used interchangeably with STPSA42-AP?

A: Yes. Both KSP42TA and MPSA42 are parametric equivalents to STPSA42-AP across all critical electrical specifications including collector current, breakdown voltage, saturation characteristics, current gain, power dissipation, and transition frequency. All three devices are configured in TO-92-3 through-hole packages with identical pin configurations.

Q: What is the primary reason for substituting STPSA42-AP?

A: STPSA42-AP is classified as obsolete. KSP42TA and MPSA42 are active products with confirmed ongoing availability, ensuring design continuity and production supply security.

Q: Are there package differences between the substitute parts?

A: All three parts utilize TO-92-3 (TO-226-3) formed leads through-hole packaging. Mechanical dimensions and pin configurations are identical, allowing direct PCB layout compatibility without redesign.

Q: Which substitute part should be selected for RoHS-compliant applications?

A: KSP42TA carries ROHS3 Compliant certification. MPSA42 RoHS status is vendor-defined and requires confirmation with the supplier for applications with mandatory RoHS compliance requirements.

Q: What is the difference in operating temperature specifications?

A: STPSA42-AP and KSP42TA specify a maximum operating temperature of 150°C. MPSA42 specifies an operating temperature range of −55°C to 150°C, providing extended low-temperature capability for applications requiring operation below 0°C.

Q: Are both substitute parts available in sufficient quantities?

A: Yes. KSP42TA has 55,300 units in stock, and MPSA42 has 27,010 units in stock, providing adequate supply for production and design implementation.

Q: Do the substitute parts maintain the same electrical characteristics?

A: Yes. KSP42TA and MPSA42 maintain identical electrical specifications to STPSA42-AP: 500 mA maximum collector current, 300 V breakdown voltage, 625 mW power dissipation, 50 MHz transition frequency, and 40 minimum DC current gain at specified test conditions.

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