KSE13003ASTU Equivalent & Substitute Parts

Part Overview

The KSE13003ASTU is an NPN bipolar junction transistor manufactured by onsemi, rated for 400 V collector-emitter breakdown voltage and 1.5 A maximum collector current. This through-hole component is housed in a TO-126-3 package and delivers 20 W maximum power dissipation with a 4 MHz transition frequency. The part is classified as obsolete, making identification of equivalent and substitute components necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value
Transistor Type	NPN
Voltage - Collector Emitter Breakdown (Max)	400 V
Current - Collector (Ic) (Max)	1.5 A
Power - Max	20 W
Frequency - Transition	4 MHz
Mounting Type	Through Hole
Package / Case	TO-126-3
Operating Temperature (Max)	150°C (TJ)

Substitute Part Grouping Explanation

Substitution of the KSE13003ASTU is determined by strict equivalence across the following electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor Type: NPN
Voltage - Collector Emitter Breakdown (Max): 400 V
Current - Collector (Ic) (Max): 1.5 A
Mounting Type: Through Hole
Operating Temperature (Max): 150°C (TJ)

Secondary Compatibility Factors:

DC Current Gain (hFE) minimum specifications
Vce Saturation characteristics
Power dissipation capability
Package compatibility (TO-126-3 or equivalent footprint)

Substitute parts are classified into two categories: direct equivalents that maintain identical electrical specifications and packaging, and similar alternatives that meet core electrical requirements while offering enhanced performance characteristics or improved product status.

Parameter Comparison

Parameter	KSE13003ASTU (Main)	FJE3303H1TU (Direct)	ST13003-K (Similar)
Manufacturer	onsemi	onsemi	STMicroelectronics
Product Status	Obsolete	Active	Active
Transistor Type	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	400 V	400 V	400 V
Current - Collector (Ic) (Max)	1.5 A	1.5 A	1.5 A
Vce Saturation (Max) @ Ib, Ic	3V @ 500mA, 1.5A	3V @ 500mA, 1.5A	1.5V @ 500mA, 1.5A
DC Current Gain (hFE) (Min) @ Ic, Vce	8 @ 500mA, 2V	8 @ 500mA, 2V	5 @ 1A, 2V
Power - Max	20 W	20 W	40 W
Frequency - Transition	4 MHz	4 MHz	Not specified
Operating Temperature (Max)	150°C (TJ)	150°C (TJ)	150°C (TJ)
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	TO-126-3	TO-126-3	SOT-32-3
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

FJE3303H1TU (Direct Equivalent): This onsemi component provides direct electrical and mechanical equivalence to the KSE13003ASTU. The FJE3303H1TU maintains identical voltage, current, and power specifications while offering active product status and ROHS3 compliance. The TO-126-3 package ensures direct footprint compatibility. This substitute is suitable for applications requiring exact performance matching with the original design.

ST13003-K (Similar Alternative): The STMicroelectronics ST13003-K meets all core electrical requirements (400 V, 1.5 A, 150°C) and offers enhanced power dissipation capability (40 W versus 20 W). The SOT-32-3 package differs from the TO-126-3, requiring PCB layout verification for mechanical fit. The ST13003-K exhibits lower Vce saturation (1.5 V versus 3 V), which may alter circuit performance in saturation-dependent applications. This component is suitable for designs where increased thermal headroom is beneficial and package footprint accommodation is feasible.

Both substitute parts carry REACH Unaffected status and active product availability, supporting long-term supply chain continuity.

Frequently Asked Questions (FAQ)

Q: Can FJE3303H1TU be used as a direct replacement for KSE13003ASTU?

A: Yes. The FJE3303H1TU is a direct equivalent, matching all electrical specifications (400 V, 1.5 A, 20 W, 4 MHz) and package type (TO-126-3). No circuit modifications are required.

Q: What are the key differences between FJE3303H1TU and ST13003-K?

A: Both parts meet the 400 V, 1.5 A core requirements. The FJE3303H1TU uses TO-126-3 packaging identical to the original part, while the ST13003-K uses SOT-32-3 packaging. The ST13003-K provides 40 W power dissipation (versus 20 W) and lower Vce saturation (1.5 V versus 3 V). Transition frequency is specified for FJE3303H1TU (4 MHz) but not for ST13003-K.

Q: Is the ST13003-K suitable for my application if I need the exact same package?

A: No. The ST13003-K uses SOT-32-3 packaging, which differs from the TO-126-3 package of the original KSE13003ASTU. PCB layout and mechanical mounting would require redesign. For identical packaging, use the FJE3303H1TU.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both FJE3303H1TU and ST13003-K are ROHS3 compliant. The original KSE13003ASTU RoHS status is not specified.

Q: What is the significance of lower Vce saturation in the ST13003-K?

A: Lower Vce saturation (1.5 V versus 3 V) reduces power dissipation during saturation operation and may alter switching characteristics. Applications relying on specific saturation voltage behavior should verify circuit performance with the ST13003-K before implementation.

Q: Can I use either substitute part interchangeably?

A: No. FJE3303H1TU is a direct replacement requiring no modifications. ST13003-K requires PCB layout changes due to different packaging and may require circuit verification due to different saturation characteristics. Select based on your specific packaging and performance requirements.

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