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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi KSE13003ASTU

Name: KSE13003ASTU
Brand: onsemi
SKU: KSE13003ASTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSE13003ASTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: KSE13003ASTU.pdf

Description:: TRANS NPN 400V 1.5A TO-126-3

Quantity:: RFQ Add To RFQ list

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Inventory:3,002

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Product details

Overview

KSE13003ASTU from ON Semiconductor is an NPN silicon power transistor designed for high-voltage switching applications, featuring V_CEO = 400 V, I_C = 1.5 A (DC), P_C = 20 W at T_C = 25°C, and h_FE = 9–16 (H1 classification). It is used in switch-mode power supplies, motor control circuits, and DC-DC converters where robust voltage handling and fast switching are required.

For engineers reviewing the KSE13003ASTU datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-126 package, 700 V V_CBO, 4 MHz f_T, t_ON/t_F switching times, and safe operating area (SOA) compliance for pulsed-load designs.

Technical Context

The KSE13003ASTU operates as a medium-power NPN bipolar junction transistor optimized for high-voltage switching rather than linear amplification. Its design emphasizes ruggedness under inductive load conditions, with specified t_STG = 4.0 ms and t_F = 0.7 ms enabling reliable turn-off in flyback and forward converter topologies.

It supports base-driven switching with V_BE(sat) = 1.0–1.2 V at I_C = 0.5–1.0 A and I_B = 0.1–0.25 A, and exhibits Cob = 21 pF at V_CB = 10 V, contributing to predictable snubber design and EMI behavior in SMPS layouts.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	400 V - Withstands 400 V collector-emitter voltage before breakdown, suitable for 380 V DC bus applications.
I_C (DC)	1.5 A - Continuous collector current rating defines maximum steady-state load-handling capability.
P_C @ T_C = 25°C	20 W - Thermal power dissipation limit at case temperature 25°C; derates linearly above 25°C per Figure 6.
h_FE (H1)	9–16 - DC current gain range at V_CE = 2 V, I_C = 0.5 A; determines required base drive current for saturation.
f_T	4 MHz - Current-gain bandwidth product indicating usable frequency limit for small-signal switching.
t_ON/t_F	1.1 ms / 0.7 ms - Measured turn-on and fall times under defined test conditions (V_CC = 125 V, R_L = 125 Ω), critical for PWM timing budget.

Pinout & Package

Package: TO-126 (short-lead variant, marked "STU" per ordering info), thermally enhanced plastic power package with collector-connected tab for heatsinking.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitting terminal for majority carriers	Low-impedance return path; connected to ground or low-side reference in common-emitter switching.
2 (Collector)	Current-collecting terminal	Connected to high-voltage rail or inductive load; tab is electrically tied to collector for thermal and electrical integration.
3 (Base)	Control input for minority carrier injection	Receives current-limited drive signal; requires ~0.1–0.5 A for full saturation depending on I_C.

Key Features

Feature	Design Value
High V_CBO	700 V collector-base breakdown enables use in high-input-voltage offline SMPS without additional clamping.
Fast switching	1.1 ms turn-on and 0.7 ms fall time support PWM frequencies up to ~500 Hz with margin for dead-time and layout parasitics.
TO-126 short-lead (STU)	Reduced lead inductance improves high-frequency stability and reduces voltage overshoot during switching transitions.
SOA-rated operation	Defined safe operating area (Figure 5) permits pulsed I_C up to 3 A with appropriate V_CE limits, supporting peak-load motor startup.

Applications

Switch-Mode Power Supply	DC Motor Driver
Use Scenario: Primary-side switching transistor in 20–50 W offline flyback converters. IC Role / Device Role / Timing Role: High-voltage NPN switch controlling energy transfer from AC line to transformer primary. Use Value: 400 V V_CEO and SOA compliance allow direct interface with rectified 380 V DC bus without series stacking.	Use Scenario: Low-frequency H-bridge or single-ended driver for 24–48 V brushed DC motors. IC Role / Device Role / Timing Role: Power stage switch enabling bidirectional or unidirectional current flow through motor windings. Use Value: 1.5 A continuous current and 3 A pulse rating support stall-current surges during motor startup and reversal.
Inductive Load Switch	Ballast Circuit
Use Scenario: Solid-state replacement for mechanical relays driving solenoids, valves, or transformers. IC Role / Device Role / Timing Role: Voltage-controlled current switch managing inductive energy storage and release. Use Value: 700 V V_CBO and 4.0 ms storage time enable robust flyback voltage suppression using external snubbers.	Use Scenario: Lamp current regulation in magnetic or hybrid fluorescent ballasts. IC Role / Device Role / Timing Role: Linear or quasi-resonant switch modulating lamp current at 20–60 kHz. Use Value: 20 W power dissipation and 150°C junction rating support sustained operation in enclosed, thermally constrained fixtures.

Switch-Mode Power Supply

DC Motor Driver

Use Scenario: Primary-side switching transistor in 20–50 W offline flyback converters.

IC Role / Device Role / Timing Role: High-voltage NPN switch controlling energy transfer from AC line to transformer primary.

Use Value: 400 V V_CEO and SOA compliance allow direct interface with rectified 380 V DC bus without series stacking.

Use Scenario: Low-frequency H-bridge or single-ended driver for 24–48 V brushed DC motors.

IC Role / Device Role / Timing Role: Power stage switch enabling bidirectional or unidirectional current flow through motor windings.

Use Value: 1.5 A continuous current and 3 A pulse rating support stall-current surges during motor startup and reversal.

Inductive Load Switch

Ballast Circuit

Use Scenario: Solid-state replacement for mechanical relays driving solenoids, valves, or transformers.

IC Role / Device Role / Timing Role: Voltage-controlled current switch managing inductive energy storage and release.

Use Value: 700 V V_CBO and 4.0 ms storage time enable robust flyback voltage suppression using external snubbers.

Use Scenario: Lamp current regulation in magnetic or hybrid fluorescent ballasts.

IC Role / Device Role / Timing Role: Linear or quasi-resonant switch modulating lamp current at 20–60 kHz.

Use Value: 20 W power dissipation and 150°C junction rating support sustained operation in enclosed, thermally constrained fixtures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN high-voltage switching transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJE13003	Same TO-126 package, identical V_CEO/I_C/P_C ratings, but h_FE min = 8 (no H-classification); f_T = 4 MHz typical.	No h_FE binning; less predictable base drive requirement across lots.	Select when h_FE consistency is non-critical and cost sensitivity outweighs gain tolerance needs.
BU508A	Higher V_CEO = 1500 V, same I_C = 1.5 A, but slower t_F = 1.5 µs (not ms), TO-220 package, no STU marking.	Designed for higher-voltage CRT flyback; not drop-in due to different package and pinout.	Choose only when >1 kV blocking is mandatory and PCB layout allows TO-220 footprint change.

Compared with MJE13003 and BU508A, the KSE13003ASTU offers factory-binned h_FE (H1), TO-126-STU short leads for lower parasitic inductance, and documented SOA curves-making it preferable for production-critical, thermally constrained, or gain-sensitive SMPS designs.

Availability

KSE13003ASTU is available at Aetrix Electronics and suitable for switch-mode power supplies, DC motor controllers, inductive load drivers, and fluorescent ballast circuits requiring stable component supply and legacy-design continuity.

Supply support for KSE13003ASTU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The KSE13003ASTU belongs to ON Semiconductor's legacy high-voltage bipolar transistor portfolio, originally developed by Fairchild for rugged, cost-effective switching in offline power conversion and motor control systems.

FAQ

What is the package type and lead configuration of the KSE13003ASTU?

The KSE13003ASTU uses the TO-126 package with short leads (denoted by "STU" suffix), featuring emitter (pin 1), collector (pin 2, tab-connected), and base (pin 3) in standard orientation. This configuration minimizes lead inductance and supports direct heatsink mounting via the collector tab, critical for thermal management in the KSE13003ASTU's 20 W power dissipation envelope.

Is the KSE13003ASTU still in active production?

No-the KSE13003ASTU is officially discontinued per ON Semiconductor documentation. However, Aetrix Electronics maintains limited legacy inventory and supports continuity planning, including cross-reference guidance and alternative sourcing strategies for the KSE13003ASTU in ongoing production programs.

What does the "H1" in KSE13003H1ASTU signify, and how does it affect circuit design?

The "H1" denotes h_FE binning: 9–16 at V_CE = 2 V and I_C = 0.5 A. For the KSE13003ASTU, this ensures predictable base drive requirements-e.g., 0.1 A base current suffices for 0.5 A collector saturation-reducing design margin uncertainty versus unbinned equivalents like the MJE13003.

Can the KSE13003ASTU replace the KSE13003H2ASTU or KSE13003H3ASTU in a design?

No-KSE13003H2ASTU (h_FE = 14–21) and KSE13003H3ASTU (h_FE = 19–26) have higher and tighter gain ranges. Substituting the KSE13003ASTU (H1) may cause insufficient saturation or increased V_CE(sat) in circuits designed for higher h_FE, risking thermal runaway or reduced efficiency unless base drive is re-optimized for the KSE13003ASTU's lower gain band.

What are the thermal limitations of the KSE13003ASTU in continuous operation?

The KSE13003ASTU has a maximum junction temperature of 150°C and dissipates 20 W at T_C = 25°C. Its thermal resistance θ_JC is approximately 1.25°C/W (derived from P_C/ΔT), meaning a 10°C rise above ambient requires ~8 W dissipation. For reliable continuous operation, heatsinking must maintain case temperature ≤80°C when the KSE13003ASTU delivers 1.5 A at V_CE(sat) ≈ 1 V.

KSE13003ASTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 1.5 A

Voltage - Collector Emitter Breakdown (Max):: 400 V

Vce Saturation (Max) @ Ib, Ic:: 3V @ 500mA, 1.5A

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: 8 @ 500mA, 2V

Power - Max:: 20 W

Frequency - Transition:: 4MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

KSE13003ASTU FAQ

1.How can I place an order for KSE13003ASTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSE13003ASTU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for KSE13003ASTU reliable?

The price and inventory of KSE13003ASTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSE13003ASTU is usually 5 days.

3.What payment methods are accepted for KSE13003ASTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSE13003ASTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSE13003ASTU?

KSE13003ASTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSE13003ASTU order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for KSE13003ASTU?

For technical support, including KSE13003ASTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSE13003ASTU requirements.

6.How does Aetrix verify that KSE13003ASTU is sourced from the original manufacturer or authorized distributors?

All KSE13003ASTU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that KSE13003ASTU meets industry standards.

7.What is the process for return or replacement of KSE13003ASTU?

All KSE13003ASTU units undergo pre-shipment inspection (PSI). If there is an issue with KSE13003ASTU, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The KSE13003ASTU part is unused and in its original packaging.

Return procedure for KSE13003ASTU:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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