KSA1381ESTSTU Equivalent & Substitute Parts

Part Overview

The KSA1381ESTSTU 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 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 KSA1381ESTSTU is classified as obsolete. Equivalent and substitute parts are available to maintain design continuity and ensure procurement availability for applications currently utilizing this transistor.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Voltage - Collector Emitter Breakdown (Max)	300	V
Current - Collector (Ic) (Max)	100	mA
Power - Max	7	W
Frequency - Transition	150	MHz
DC Current Gain (hFE) (Min) @ Ic, Vce	100 @ 10mA, 10V	—
Vce Saturation (Max) @ Ib, Ic	600mV @ 2mA, 20mA	—
Operating Temperature Range	-55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-126-3	—

Substitute Part Grouping Explanation

Substitute parts for the KSA1381ESTSTU are classified into two categories based on electrical and mechanical compatibility:

Parametric Equivalent: Parts that maintain identical or equivalent electrical specifications and package configuration, allowing direct replacement without circuit modification.

Similar Substitute: Parts that share the same transistor type (PNP), voltage rating (300 V), and through-hole mounting, but with different current and power ratings. These parts are suitable for applications where the original specifications exceed circuit requirements.

The substitution logic is based on the following key parameters:

Transistor Type: PNP
Voltage - Collector Emitter Breakdown: 300 V (minimum requirement)
Mounting Type: Through Hole
Package Compatibility: TO-126-3 or equivalent through-hole package

Parameter Comparison

Parameter	KSA1381ESTSTU	KSA1381ESTU	MJE350G	MJE350
Manufacturer	onsemi	onsemi	onsemi	STMicroelectronics
Product Status	Obsolete	Active	Active	Active
Transistor Type	PNP	PNP	PNP	PNP
Voltage - Collector Emitter Breakdown (Max)	300 V	300 V	300 V	300 V
Current - Collector (Ic) (Max)	100 mA	100 mA	500 mA	500 mA
Power - Max	7 W	7 W	20 W	20.8 W
Frequency - Transition	150 MHz	150 MHz	—	—
DC Current Gain (hFE) (Min) @ Ic, Vce	100 @ 10mA, 10V	100 @ 10mA, 10V	30 @ 50mA, 10V	30 @ 50mA, 10V
Vce Saturation (Max) @ Ib, Ic	600mV @ 2mA, 20mA	600mV @ 2mA, 20mA	—	—
Operating Temperature Range	-55 to 150 °C	-55 to 150 °C	-65 to 150 °C	150 °C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	TO-126-3	TO-126-3	TO-126	SOT-32-3
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

KSA1381ESTU (onsemi): This part is the direct parametric equivalent to the KSA1381ESTSTU. It maintains identical electrical specifications, including 100 mA collector current, 7 W power rating, 150 MHz transition frequency, and TO-126-3 package configuration. The KSA1381ESTU is classified as Active product status and is ROHS3 compliant, making it the primary replacement for obsolete KSA1381ESTSTU applications. The only difference is packaging format (Tube versus Bulk).

MJE350G (onsemi): This part is a similar substitute suitable for applications where collector current and power dissipation requirements do not exceed 500 mA and 20 W respectively. The MJE350G maintains the 300 V voltage rating and through-hole mounting configuration. It is ROHS3 compliant and Active product status. The lower DC current gain (30 versus 100) and absence of transition frequency specification require circuit verification for high-frequency applications.

MJE350 (STMicroelectronics): This part is a similar substitute with identical electrical ratings to the MJE350G (500 mA, 20.8 W, 300 V). It is manufactured by STMicroelectronics and packaged in SOT-32-3 configuration. The MJE350 is ROHS3 compliant and Active product status. Package differences (SOT-32-3 versus TO-126-3) require physical board layout verification.

Frequently Asked Questions (FAQ)

Q: Can KSA1381ESTU be used as a direct replacement for KSA1381ESTSTU?

A: Yes. The KSA1381ESTU is a parametric equivalent with identical electrical specifications (100 mA, 7 W, 300 V, 150 MHz, TO-126-3 package). The parts differ only in packaging format and product status. KSA1381ESTU is Active and ROHS3 compliant.

Q: What are the differences between KSA1381ESTU and MJE350G?

A: The KSA1381ESTU is rated for 100 mA collector current and 7 W power dissipation with 150 MHz transition frequency. The MJE350G is rated for 500 mA collector current and 20 W power dissipation with unspecified transition frequency. The MJE350G has lower DC current gain (30 versus 100). Both maintain 300 V voltage rating and through-hole mounting.

Q: Can MJE350 and MJE350G be used interchangeably?

A: MJE350 and MJE350G share identical electrical specifications (500 mA, 300 V, 20+ W power rating, 30 DC current gain). The primary difference is package configuration: MJE350 uses SOT-32-3 while MJE350G uses TO-126. Physical board layout compatibility must be verified before substitution.

Q: Is the MJE350 suitable for high-frequency applications?

A: The MJE350 does not have a specified transition frequency parameter. Applications requiring 150 MHz operation should use KSA1381ESTU or KSA1381ESTSTU, which are rated for 150 MHz transition frequency.

Q: What is the operating temperature range for each substitute?

A: KSA1381ESTSTU and KSA1381ESTU operate from -55°C to 150°C. MJE350G operates from -65°C to 150°C. MJE350 (STMicroelectronics) specifies 150°C maximum operating temperature without lower limit specification.

Q: Are all substitute parts ROHS3 compliant?

A: KSA1381ESTU, MJE350G, and MJE350 are all ROHS3 compliant. The original KSA1381ESTSTU does not have RoHS status specified. All parts maintain REACH Unaffected status.

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