MPSA42RA Equivalent & Substitute Parts

Part Overview

The MPSA42RA is an NPN bipolar junction transistor manufactured by onsemi, rated for 300 V collector-emitter breakdown voltage and 500 mA maximum collector current. This device is packaged in a TO-92-3 through-hole configuration and is designed for general-purpose switching and amplification applications. The MPSA42RA is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain electrical compatibility across critical parameters including voltage rating, current capacity, and thermal characteristics.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	300	V
Current - Collector (Ic) (Max)	500	mA
Power - Max	625	mW
Frequency - Transition	50	MHz
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 30mA, 10V	—
Vce Saturation (Max) @ Ib, Ic	500mV @ 2mA, 20mA	—
Current - Collector Cutoff (Max)	100	nA
Operating Temperature Range	-55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-92-3	—

Substitute Part Grouping Explanation

Substitute parts for the MPSA42RA are classified into three categories based on electrical and mechanical compatibility:

Direct Manufacturer Substitutes maintain identical electrical specifications and are sourced from the original manufacturer or authorized equivalents. These parts satisfy all critical parameters: 300 V breakdown voltage, 500 mA collector current, 625 mW power dissipation, and 50 MHz transition frequency.

Similar Manufacturer Substitutes are sourced from alternative manufacturers and may exceed the original specifications in one or more parameters. These parts maintain the core electrical requirements (300 V or higher breakdown voltage, 500 mA collector current) but may offer enhanced performance characteristics such as higher power dissipation (1 W), higher transition frequency (75 MHz), or extended operating temperature ranges (-55°C to 200°C).

Parametric Equivalents are functionally identical parts from different manufacturers with identical electrical specifications and package compatibility. These parts are suitable for direct replacement in applications where the original part is unavailable.

Substitution eligibility is determined by the following key parameters:

Voltage - Collector Emitter Breakdown (minimum 300 V)
Current - Collector (minimum 500 mA)
Transistor Type (NPN)
Mounting Type (Through Hole)
Package Compatibility (TO-92-3 or TO-92 compatible)

Parameter Comparison

Part Number	Manufacturer	Vce Breakdown (V)	Ic Max (mA)	Power Max (mW)	Frequency (MHz)	hFE Min @ Ic, Vce	Temp Range (°C)	Package	Status
MPSA42RA	onsemi	300	500	625	50	40 @ 30mA, 10V	-55 to 150	TO-92-3	Obsolete
KSP42TA	onsemi	300	500	625	50	40 @ 30mA, 10V	-55 to 150	TO-92-3	Active
MPSA42	Diotec Semiconductor	300	500	625	50	40 @ 30mA, 10V	-55 to 150	TO-92-3	Active
ZTX657	Diodes Incorporated	300	500	1000	30	50 @ 100mA, 5V	-55 to 200	E-Line (TO-92 compatible)	Active
ZTX657STZ	Diodes Incorporated	300	500	1000	30	50 @ 100mA, 5V	-55 to 200	E-Line (TO-92 compatible)	Active
ZTX457STZ	Diodes Incorporated	300	500	1000	75	50 @ 50mA, 10V	-55 to 200	E-Line (TO-92 compatible)	Active
ZTX658STZ	Diodes Incorporated	400	500	1000	50	50 @ 100mA, 5V	-55 to 200	E-Line (TO-92 compatible)	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): Select KSP42TA (onsemi) or MPSA42 (Diotec Semiconductor) when exact electrical and thermal specifications of the MPSA42RA must be maintained. Both parts are active products with identical voltage, current, power, and frequency ratings. KSP42TA is available in Cut Tape packaging with 55,300 units in stock. MPSA42 is available in Cut Tape packaging with 27,010 units in stock. Both parts are RoHS3 compliant and REACH unaffected.

For Enhanced Performance Applications: Select ZTX657, ZTX657STZ, ZTX457STZ, or ZTX658STZ (Diodes Incorporated) when applications require extended operating temperature ranges (-55°C to 200°C) or higher power dissipation (1 W). These parts maintain the 300 V minimum breakdown voltage and 500 mA collector current specifications. ZTX657 and ZTX657STZ offer lower transition frequency (30 MHz) suitable for lower-speed applications. ZTX457STZ provides higher transition frequency (75 MHz) for faster switching applications. ZTX658STZ offers the highest breakdown voltage (400 V) for applications requiring additional voltage margin. All Diodes Incorporated parts are RoHS3 compliant and REACH unaffected.

Compliance Considerations: All substitute parts listed are RoHS3 compliant or ROHS3 compliant. The MPSA42RA is REACH unaffected; all substitute parts maintain REACH unaffected status. Moisture sensitivity level is 1 (Unlimited) for all parts, indicating no special moisture handling requirements.

Frequently Asked Questions (FAQ)

Q: Can KSP42TA be used as a direct replacement for MPSA42RA? A: Yes. KSP42TA is manufactured by onsemi and maintains identical electrical specifications: 300 V breakdown voltage, 500 mA collector current, 625 mW power dissipation, 50 MHz transition frequency, and -55°C to 150°C operating temperature range. Both parts use TO-92-3 packaging. KSP42TA is an active product with higher inventory availability.

Q: What is the difference between ZTX657 and ZTX657STZ? A: Both parts are manufactured by Diodes Incorporated and share identical electrical specifications. The difference is packaging: ZTX657 is supplied in Bulk packaging, while ZTX657STZ is supplied in Tape & Box (TB) packaging. Electrical performance and compatibility are equivalent.

Q: Can ZTX658STZ be used in place of MPSA42RA? A: ZTX658STZ is electrically compatible with MPSA42RA for applications where the higher 400 V breakdown voltage is acceptable. Both parts maintain 500 mA collector current and 50 MHz transition frequency. ZTX658STZ offers 1 W power dissipation compared to 625 mW, and an extended operating temperature range of -55°C to 200°C. Physical compatibility is maintained through E-Line (TO-92 compatible) packaging.

Q: Are there any thermal performance differences between substitute parts? A: Yes. MPSA42RA and its direct replacements (KSP42TA, MPSA42) are rated for 625 mW maximum power dissipation with an operating temperature range of -55°C to 150°C. Diodes Incorporated substitutes (ZTX657, ZTX657STZ, ZTX457STZ, ZTX658STZ) are rated for 1 W maximum power dissipation with an extended operating temperature range of -55°C to 200°C. Applications requiring higher power dissipation or operation at elevated temperatures should select Diodes Incorporated parts.

Q: What is the difference between ZTX457STZ and ZTX657STZ? A: Both parts are manufactured by Diodes Incorporated and share identical voltage (300 V) and current (500 mA) ratings. The primary difference is transition frequency: ZTX457STZ operates at 75 MHz while ZTX657STZ operates at 30 MHz. ZTX457STZ is suitable for higher-speed switching applications, while ZTX657STZ is suitable for lower-speed applications. DC current gain specifications also differ: ZTX457STZ has hFE minimum of 50 @ 50mA, 10V, while ZTX657STZ has hFE minimum of 50 @ 100mA, 5V.

Q: Is the MPSA42 from Diotec Semiconductor identical to the original MPSA42RA? A: MPSA42 from Diotec Semiconductor maintains identical electrical specifications to MPSA42RA: 300 V breakdown voltage, 500 mA collector current, 625 mW power dissipation, 50 MHz transition frequency, and -55°C to 150°C operating temperature range. Both use TO-92-3 packaging. The primary difference is manufacturer and product status: MPSA42 is an active product with higher inventory availability.

Q: Are all substitute parts RoHS compliant? A: All substitute parts listed are either RoHS3 compliant or ROHS3 compliant. The original MPSA42RA does not have RoHS status specified. All parts maintain REACH unaffected status.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message