2SA1381FSTU Equivalent & Substitute Parts

Part Overview

The 2SA1381FSTU is a PNP bipolar junction transistor manufactured by onsemi, rated for 300 V collector-emitter breakdown voltage and 100 mA maximum collector current. This component is packaged in a TO-126-3 through-hole configuration and is designed for general-purpose switching and amplification applications requiring moderate power dissipation up to 7 W.

The 2SA1381FSTU is classified as an obsolete product. Identifying equivalent and substitute parts is necessary to support ongoing maintenance, repair, and redesign activities for legacy equipment and systems utilizing this transistor.

Substiute Parts

2SA1381FSTU

onsemiIn Stock: 11072SA1381FSTU Datasheet

Current PartRFQ

MJE350G

onsemiIn Stock: 20158MJE350G Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2SA1381FSTU is determined by the following critical parameters:

Mandatory Matching Criteria:

• Transistor Type: PNP configuration
• Voltage - Collector Emitter Breakdown (Max): 300 V minimum
• Mounting Type: Through Hole
• Package / Case: TO-126 or TO-225AA compatible footprints

Allowable Parameter Variations:

• Current - Collector (Ic) (Max): Substitute must equal or exceed 100 mA
• Power - Max: Substitute must equal or exceed 7 W
• Frequency - Transition: Substitute may differ if application requirements permit
• Operating Temperature Range: Substitute must encompass or exceed the specified range
• DC Current Gain (hFE): Substitute values may differ within acceptable circuit design margins

The MJE350G meets the mandatory matching criteria and provides enhanced electrical performance characteristics, including higher maximum collector current (500 mA) and greater power dissipation capability (20 W), while maintaining the same 300 V breakdown voltage rating and through-hole TO-126 package configuration.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: MJE350G

The MJE350G is the recommended substitute for the obsolete 2SA1381FSTU. Both components are manufactured by onsemi and share identical voltage ratings (300 V breakdown) and through-hole package families (TO-126 series). The MJE350G is classified as an active product with current manufacturing support and availability.

The MJE350G provides superior electrical performance with 500 mA maximum collector current and 20 W power dissipation, compared to the 2SA1381FSTU specifications of 100 mA and 7 W respectively. This enhanced capability allows the MJE350G to operate in applications requiring higher current handling or power dissipation without exceeding voltage or thermal constraints.

Both components maintain REACH compliance and EAR99 export classification status. The MJE350G extends the operating temperature range to -65°C, providing additional margin for low-temperature applications.

Footprint compatibility between TO-126-3 and TO-126 packages permits direct mechanical substitution in through-hole circuit board layouts without requiring PCB redesign.

Frequently Asked Questions (FAQ)

Q: Can the MJE350G directly replace the 2SA1381FSTU in existing circuit boards?

A: Yes. Both transistors utilize compatible through-hole package configurations (TO-126 family) with identical pin assignments for PNP transistors (Collector, Base, Emitter). Direct mechanical substitution is possible without PCB modification.

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

A: The MJE350G provides higher maximum collector current (500 mA versus 100 mA) and greater power dissipation capability (20 W versus 7 W). Both maintain the same 300 V collector-emitter breakdown voltage rating. The MJE350G has a lower minimum DC current gain (30 @ 50mA, 10V) compared to the 2SA1381FSTU (160 @ 10mA, 10V), which may affect circuit biasing calculations.

Q: Is the MJE350G suitable for all applications using the 2SA1381FSTU?

A: The MJE350G is suitable for applications where the 2SA1381FSTU was used, provided that circuit design accounts for the different DC current gain characteristics. The enhanced current and power ratings of the MJE350G do not create incompatibility; however, base current biasing networks may require adjustment to achieve equivalent circuit performance.

Q: What is the product status difference between these transistors?

A: The 2SA1381FSTU is classified as obsolete and no longer manufactured. The MJE350G is an active product with ongoing manufacturing support and commercial availability. For new designs and long-term supply chain planning, the MJE350G is the appropriate selection.

Q: Are there compliance or regulatory differences between these parts?

A: Both transistors maintain identical REACH compliance status (REACH Unaffected) and export classification (EAR99). The MJE350G carries RoHS3 compliance certification, whereas the 2SA1381FSTU does not specify RoHS status. For applications requiring RoHS compliance, the MJE350G satisfies this requirement.

Q: What is the operating temperature range difference?

A: The 2SA1381FSTU operates from -55°C to 150°C. The MJE350G extends the lower temperature limit to -65°C, providing an additional 10°C margin for cold-temperature applications. Both transistors share the same 150°C upper temperature limit.