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

onsemi KSE800STSSTU

Name: KSE800STSSTU
Brand: onsemi
SKU: KSE800STSSTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSE800STSSTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSE800STSSTU.pdf

Description:: TRANS NPN DARL 60V 4A TO-126-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSE800STSSTU from onsemi is an NPN epitaxial silicon Darlington transistor in TO-126-3LD package, rated for 60 V V_CEO, 4 A I_C, and 40 W P_C at T_C = 25°C, with monolithic construction including built-in base-emitter resistors (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ), delivering h_FE ≥ 750 at I_C = 1.5 A for high-gain switching in industrial motor drivers.

For engineers reviewing the KSE800STSSTU datasheet, pinout, applications, or equivalent options, key selection criteria include verified DC current gain stability across 1.5–4 A load range, saturation voltage ≤3.0 V at I_C = 4 A / I_B = 40 mA, and Pb-free TO-126-3LD thermal performance validated to 150°C junction temperature.

Technical Context

The KSE800STSSTU implements a monolithic Darlington pair with integrated biasing resistors, eliminating external base resistor networks. Its structure enables high h_FE ≥ 750 at low base drive (I_B = 30 mA) while maintaining V_CE(sat) ≤ 2.5 V at I_C = 1.5 A - critical for efficient medium-power linear and switching amplification.

Designed as a complement to the KSE700 PNP Darlington, it supports push-pull output stages requiring matched gain and voltage ratings. Absolute maximum ratings are strictly defined at T_C = 25°C, with power derating linear above 25°C per Figure 6, and safe operating area (SOA) bounded by second breakdown limits up to 100 μs pulse width.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	60 V - Maximum collector-emitter voltage before breakdown; defines usable rail voltage in relay drivers and lamp controls.
I_C	4 A - Continuous collector current rating; supports sustained 3–5 W load switching without forced cooling.
h_FE	≥750 @ I_C = 1.5 A - High DC current gain reduces required base drive current, easing microcontroller GPIO interface design.
V_CE(sat)	≤3.0 V @ I_C = 4 A / I_B = 40 mA - Low saturation voltage minimizes conduction loss in high-current switching applications.
P_C	40 W @ T_C = 25°C - Thermal limit at case temperature; requires heatsink for >10 W continuous dissipation.
T_J	150°C - Maximum junction temperature; sets upper bound for ambient + thermal resistance × power design margin.

Pinout & Package

Package: TO-126-3LD (Case 340AS), surface-mount compatible through-hole package with integral heat slug; pin 2 (Collector) electrically connected to tab for direct heatsinking.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current sink terminal; internally tied to emitter of internal Darlington's output transistor.
2	Collector	Main current path output; electrically bonded to metal tab for thermal and electrical connection to heatsink.
3	Base	Control input; connects to internal resistor network (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ) enabling single-resistor drive.

Key Features

Feature	Design Value
Monolithic Darlington with R1/R2	Eliminates external base bias resistors; simplifies PCB layout and improves reliability over discrete resistor-transistor assemblies.
h_FE ≥ 750 @ I_C = 1.5 A	Enables direct drive from 3.3 V/5 V logic outputs with <30 mA base current, reducing need for pre-driver stages.
V_CE(sat) ≤ 2.5 V @ I_C = 1.5 A	Reduces power loss to <3.75 W at full rated current, improving thermal efficiency in compact enclosures.
Pb-free TO-126-3LD	Complies with RoHS Directive 2011/65/EU; eliminates lead-based solder compatibility concerns in modern assembly lines.

Applications

Industrial Relay Drivers	DC Motor Speed Controllers
Use Scenario: Driving 24 V/2 A electromagnetic relays in PLC output modules where space and component count are constrained. IC Role / Device Role / Timing Role: High-gain Darlington switch providing galvanic isolation between low-power control logic and inductive relay coil. Use Value: Delivers guaranteed h_FE ≥ 750 at 1.5 A ensures reliable turn-on with ≤20 mA MCU GPIO drive, minimizing BOM cost and board area.	Use Scenario: PWM-controlled bidirectional DC motor driver stage in warehouse automation conveyors. IC Role / Device Role / Timing Role: Medium-power output switch in H-bridge half-bridge configuration handling 36 V/3 A loads. Use Value: V_CEO = 60 V and SOA-rated pulse capability support 48 V bus transients; V_CE(sat) ≤ 3.0 V limits conduction loss during 10–20 kHz PWM operation.
Lamp Dimming Circuits	Power Supply Pass Transistors
Use Scenario: Phase-cut dimmer output stage controlling 120 VAC incandescent lamps via TRIAC-triggered gate drive. IC Role / Device Role / Timing Role: Current amplifier for optocoupler output driving TRIAC gate with precise timing margins. Use Value: Fast turn-on response and stable h_FE across temperature ensure consistent zero-crossing trigger timing and flicker-free dimming.	Use Scenario: Linear pass element in 5 V/3 A adjustable bench power supply with foldback current limiting. IC Role / Device Role / Timing Role: Series pass transistor regulating output voltage under variable load conditions. Use Value: 40 W P_C rating and 150°C T_J allow safe operation at 15 W dissipation with standard heatsink, supporting ±3% regulation accuracy.

Industrial Relay Drivers

DC Motor Speed Controllers

Use Scenario: Driving 24 V/2 A electromagnetic relays in PLC output modules where space and component count are constrained.

IC Role / Device Role / Timing Role: High-gain Darlington switch providing galvanic isolation between low-power control logic and inductive relay coil.

Use Value: Delivers guaranteed h_FE ≥ 750 at 1.5 A ensures reliable turn-on with ≤20 mA MCU GPIO drive, minimizing BOM cost and board area.

Use Scenario: PWM-controlled bidirectional DC motor driver stage in warehouse automation conveyors.

IC Role / Device Role / Timing Role: Medium-power output switch in H-bridge half-bridge configuration handling 36 V/3 A loads.

Use Value: V_CEO = 60 V and SOA-rated pulse capability support 48 V bus transients; V_CE(sat) ≤ 3.0 V limits conduction loss during 10–20 kHz PWM operation.

Lamp Dimming Circuits

Power Supply Pass Transistors

Use Scenario: Phase-cut dimmer output stage controlling 120 VAC incandescent lamps via TRIAC-triggered gate drive.

IC Role / Device Role / Timing Role: Current amplifier for optocoupler output driving TRIAC gate with precise timing margins.

Use Value: Fast turn-on response and stable h_FE across temperature ensure consistent zero-crossing trigger timing and flicker-free dimming.

Use Scenario: Linear pass element in 5 V/3 A adjustable bench power supply with foldback current limiting.

IC Role / Device Role / Timing Role: Series pass transistor regulating output voltage under variable load conditions.

Use Value: 40 W P_C rating and 150°C T_J allow safe operation at 15 W dissipation with standard heatsink, supporting ±3% regulation accuracy.

Equivalent & Alternatives

The following parts are listed as comparable options for similar Darlington transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD122G	TO-252 (DPAK), h_FE ≥ 1000 @ I_C = 2 A, V_CEO = 100 V, P_D = 30 W	Higher voltage rating but lower power dissipation; unsuitable for >25 W continuous use without aggressive heatsinking	Preferred when higher V_CEO margin is needed and surface-mount assembly is required
BD679A	TO-126, h_FE ≥ 750 @ I_C = 2 A, V_CEO = 80 V, P_C = 30 W, no built-in resistors	Requires external base resistor network; higher V_CEO but lower thermal capability than KSE800STSSTU	Selected when discrete bias control is preferred or legacy designs require resistor customization

Compared with MJD122G and BD679A, the KSE800STSSTU offers superior thermal capacity (40 W vs. ≤30 W) and integrated biasing in the same TO-126 footprint, making it optimal for high-reliability, medium-power linear switching where board space and component count are constrained.

Availability

KSE800STSSTU is available at Aetrix Electronics and suitable for industrial relay drivers, DC motor speed controllers, lamp dimming circuits, and linear power supply pass elements requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for KSE800STSSTU 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient innovation for automotive, industrial, cloud, and IoT applications.

The KSE800STSSTU belongs to onsemi's discrete power transistor product line, engineered for robust, high-gain switching in industrial control and power management systems where reliability under thermal stress is critical.

FAQ

What is the maximum continuous collector current rating for the KSE800STSSTU?

The KSE800STSSTU has a maximum continuous collector current (I_C) rating of 4 A at case temperature T_C = 25°C. Derating is required above this temperature per the linear power derating curve in Figure 6 of the datasheet; at T_C = 100°C, usable I_C drops to approximately 2.4 A. This rating assumes proper heatsinking and adherence to SOA limits for pulsed operation.

Does the KSE800STSSTU include internal base-emitter resistors?

Yes, the KSE800STSSTU features monolithic construction with two built-in base-emitter resistors: R1 ≈ 10 kΩ and R2 ≈ 0.6 kΩ, as shown in the equivalent circuit diagram. These resistors enable single-pin base drive without external components, simplifying circuit design and improving reliability compared to discrete Darlington configurations.

What is the collector-emitter saturation voltage of the KSE800STSSTU at full rated current?

The KSE800STSSTU exhibits V_CE(sat) ≤ 3.0 V at I_C = 4 A and I_B = 40 mA, per the Electrical Characteristics table. At lower current (I_C = 1.5 A / I_B = 30 mA), V_CE(sat) is ≤ 2.5 V. These values reflect actual device performance under specified test conditions and define conduction losses in switching applications.

Is the KSE800STSSTU RoHS-compliant and lead-free?

Yes, the KSE800STSSTU is a Pb-free device, explicitly stated in the Features section and confirmed in the Ordering Information table (suffix "STU" denotes Pb-free TO-126-3LD packaging). It complies with EU RoHS Directive 2011/65/EU and is suitable for environmentally regulated manufacturing environments.

What is the safe operating area (SOA) limitation for the KSE800STSSTU during pulsed operation?

The KSE800STSSTU SOA is defined in Figure 5 of the datasheet, covering DC, 1 ms, 5 ms, 10 ms, and 100 μs pulse widths. At V_CE = 40 V, maximum allowable I_C is ~2.5 A for 10 ms pulses and ~4.5 A for 100 μs pulses. Second breakdown limits dominate beyond these boundaries, requiring careful pulse-width and duty-cycle validation in high-speed switching designs.

KSE800STSSTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN - Darlington

Current - Collector (Ic) (Max):: 4 A

Voltage - Collector Emitter Breakdown (Max):: 60 V

Vce Saturation (Max) @ Ib, Ic:: 2.5V @ 30mA, 1.5A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 750 @ 1.5A, 3V

Power - Max:: 40 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

KSE800STSSTU FAQ

1.How can I place an order for KSE800STSSTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSE800STSSTU 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 KSE800STSSTU reliable?

The price and inventory of KSE800STSSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSE800STSSTU is usually 5 days.

3.What payment methods are accepted for KSE800STSSTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSE800STSSTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSE800STSSTU?

KSE800STSSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSE800STSSTU 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 KSE800STSSTU?

For technical support, including KSE800STSSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSE800STSSTU requirements.

6.How does Aetrix verify that KSE800STSSTU is sourced from the original manufacturer or authorized distributors?

All KSE800STSSTU 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 KSE800STSSTU meets industry standards.

7.What is the process for return or replacement of KSE800STSSTU?

All KSE800STSSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSE800STSSTU, 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 KSE800STSSTU part is unused and in its original packaging.

Return procedure for KSE800STSSTU:

1.Submit a request within 90 days.

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

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