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

onsemi KSE200STSTU

Name: KSE200STSTU
Brand: onsemi
SKU: KSE200STSTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSE200STSTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSE200STSTU.pdf

Description:: TRANS NPN 25V 5A TO-126-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSE200STSTU from ON Semiconductor (formerly Fairchild) is an NPN epitaxial silicon power transistor in TO-126 package, rated for 5 A collector current, 25 V V_CEO, and 15 W power dissipation at T_C = 25°C; used as a medium-power switching or linear amplifier in DC-DC converters, motor drivers, and relay drivers.

For engineers reviewing the KSE200STSTU datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CE(sat) ≤ 1.8 V at I_C = 5 A / I_B = 1 A, h_FE ≥ 10 at full-rated current, f_T = 65 MHz, and safe operating area compliance per Figure 4 of the original Fairchild datasheet.

Technical Context

This NPN bipolar junction transistor operates with base-emitter forward biasing to control high-current collector paths. Its design emphasizes low saturation voltage and stable gain across 500 mA–5 A load range, supported by specified h_FE minima at multiple I_C points (70 @ 500 mA, 45 @ 2 A, 10 @ 5 A).

The device features a 65 MHz current-gain bandwidth product under V_CE = 10 V / I_C = 100 mA conditions and exhibits 80 pF output capacitance at V_CB = 10 V, enabling use in moderate-frequency switching applications up to several hundred kHz without excessive switching loss penalties.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	25 V - Maximum allowable collector-emitter voltage before breakdown under open-base condition; defines upper limit for DC bus or flyback clamp voltage handling.
I_C	5 A - Continuous collector current rating at T_C = 25°C; usable up to ~3.5 A at 80°C case temperature per derating curve.
P_C	15 W - Maximum power dissipation at T_C = 25°C; requires heatsinking for sustained >2 A operation.
h_FE	10–180 - DC current gain range; minimum 10 at I_C = 5 A ensures reliable saturation drive with I_B ≥ 0.5 A.
V_CE(sat)	1.8 V max @ I_C = 5 A / I_B = 1 A - Low on-state voltage reduces conduction loss in switching applications.
f_T	65 MHz - Current-gain bandwidth product; supports stable amplification or switching up to ~5–10 MHz small-signal operation.
C_ob	80 pF @ V_CB = 10 V - Output junction capacitance impacts turn-off speed and EMI in hard-switched topologies.

Pinout & Package

Package: TO-126 plastic power package with integral mounting tab (collector-connected), standardized for vertical PCB mounting and heatsink interface.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitting terminal for majority carriers	Low-impedance return path; connects to ground or low-side reference in common-emitter configurations.
2 (Collector)	Current-collecting terminal	Internally bonded to metal tab; electrically tied to heatsink-requires insulation if heatsink is grounded.
3 (Base)	Control electrode for carrier injection	Receives drive current to modulate collector current; requires series resistor to limit I_B and ensure saturation.

Key Features

Feature	Design Value
Low V_CE(sat)	1.8 V max at full 5 A rating enables <10 W conduction loss in high-current switch mode.
High f_T	65 MHz bandwidth supports stable small-signal amplification and fast switching transitions.
Complementary pairing	Designed as NPN counterpart to KSE210 PNP transistor for push-pull or H-bridge output stages.
Robust SOA	Forward-bias safe operating area (Figure 4) supports pulse currents up to 10 A with appropriate time limits.

Applications

DC-DC Converter Switch	DC Motor Driver Stage
Use Scenario: Used as main switching transistor in non-isolated buck or boost converter operating at ≤200 kHz with 12–24 V input and ≤5 A output. IC Role / Device Role / Timing Role: Power switching element controlled by PWM signal; handles high peak current during on-time while sustaining off-state voltage. Use Value: Low V_CE(sat) minimizes conduction loss; 15 W thermal rating allows compact heatsink integration in space-constrained industrial supplies.	Use Scenario: Drives brushed DC motors in 12–24 V systems requiring bidirectional control via external H-bridge configuration. IC Role / Device Role / Timing Role: High-current half-bridge leg; switches motor winding current with base-driven saturation and controlled turn-off. Use Value: Verified h_FE ≥ 45 at 2 A ensures robust drive margin; TO-126 mechanical stability supports vibration-prone automotive and industrial mounting.
Relay Driver Circuit	Linear Regulator Pass Element
Use Scenario: Interfaces microcontroller GPIO to energize 12–24 V electromagnetic relays with coil currents up to 500 mA–2 A. IC Role / Device Role / Timing Role: Single-stage current amplifier; provides sufficient I_C gain to fully saturate relay coil without excessive base drive burden. Use Value: Guaranteed h_FE ≥ 70 at 500 mA simplifies base resistor selection; low V_BE(sat) = 2.5 V ensures compatibility with 3.3 V/5 V logic levels.	Use Scenario: Serves as pass transistor in adjustable linear regulators delivering up to 3 A continuous output with 5–15 V dropout. IC Role / Device Role / Timing Role: Series regulation element dissipating excess input-output voltage as heat; biased in active region for precise voltage control. Use Value: 150°C maximum junction temperature and defined power derating curve (Figure 5) allow predictable thermal design in enclosed enclosures.

DC-DC Converter Switch

DC Motor Driver Stage

Use Scenario: Used as main switching transistor in non-isolated buck or boost converter operating at ≤200 kHz with 12–24 V input and ≤5 A output.

IC Role / Device Role / Timing Role: Power switching element controlled by PWM signal; handles high peak current during on-time while sustaining off-state voltage.

Use Value: Low V_CE(sat) minimizes conduction loss; 15 W thermal rating allows compact heatsink integration in space-constrained industrial supplies.

Use Scenario: Drives brushed DC motors in 12–24 V systems requiring bidirectional control via external H-bridge configuration.

IC Role / Device Role / Timing Role: High-current half-bridge leg; switches motor winding current with base-driven saturation and controlled turn-off.

Use Value: Verified h_FE ≥ 45 at 2 A ensures robust drive margin; TO-126 mechanical stability supports vibration-prone automotive and industrial mounting.

Relay Driver Circuit

Linear Regulator Pass Element

Use Scenario: Interfaces microcontroller GPIO to energize 12–24 V electromagnetic relays with coil currents up to 500 mA–2 A.

IC Role / Device Role / Timing Role: Single-stage current amplifier; provides sufficient I_C gain to fully saturate relay coil without excessive base drive burden.

Use Value: Guaranteed h_FE ≥ 70 at 500 mA simplifies base resistor selection; low V_BE(sat) = 2.5 V ensures compatibility with 3.3 V/5 V logic levels.

Use Scenario: Serves as pass transistor in adjustable linear regulators delivering up to 3 A continuous output with 5–15 V dropout.

IC Role / Device Role / Timing Role: Series regulation element dissipating excess input-output voltage as heat; biased in active region for precise voltage control.

Use Value: 150°C maximum junction temperature and defined power derating curve (Figure 5) allow predictable thermal design in enclosed enclosures.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD200G	Same TO-126 package; V_CEO = 25 V, I_C = 5 A, but h_FE min = 20 @ 5 A (vs. 10 for KSE200STSTU); V_CE(sat) = 1.5 V max.	Slightly tighter gain tolerance and lower saturation voltage support more consistent drive in production batches.	Preferred where higher h_FE consistency or lower conduction loss is critical; same footprint and biasing.
BD139	TO-126 package; V_CEO = 80 V, I_C = 1.5 A, h_FE = 25–250; lower current rating but higher voltage capability.	Not suitable for 5 A loads; applicable only in lower-current, higher-voltage linear or switching roles (e.g., 48 V supply interfaces).	Select when system voltage exceeds 25 V but current demand is ≤1.5 A; requires redesign of base drive and thermal layout.

Compared with MJD200G and BD139, the KSE200STSTU offers the lowest V_CE(sat) among TO-126 NPNs rated for 5 A, with verified gain down to full load-making it optimal for cost-sensitive, thermally constrained 24 V industrial switching where drive simplicity and conduction efficiency are prioritized over voltage headroom.

Availability

KSE200STSTU is available at Aetrix Electronics and suitable for DC-DC converters, motor drivers, and relay interface circuits requiring stable component supply and long-term industrial availability.

Supply support for KSE200STSTU 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 (acquired Fairchild Semiconductor in 2016) designs and manufactures high-performance analog, discrete, and power management semiconductors for industrial, automotive, and computing applications.

The KSE200STSTU belongs to Fairchild's legacy general-purpose power transistor family, engineered for reliability and ease of use in medium-power linear and switching applications where proven performance outweighs cutting-edge specs.

FAQ

What is the maximum continuous collector current for KSE200STSTU?

The KSE200STSTU is rated for 5 A continuous collector current at case temperature T_C = 25°C. Derating is required above this temperature-per Figure 5 in the original Fairchild datasheet, current must be reduced linearly to ~3.5 A at T_C = 80°C and to zero at T_C = 150°C. Operation beyond these limits risks thermal runaway or bond-wire failure.

Is KSE200STSTU pin-compatible with other TO-126 transistors like MJD200G?

Yes, KSE200STSTU uses the standard TO-126 package with identical pinout: Pin 1 = Emitter, Pin 2 = Collector (tab), Pin 3 = Base. The MJD200G shares this mechanical and electrical pin assignment, enabling direct PCB replacement without layout changes-provided thermal and gain requirements are verified.

What is the typical V_BE(sat) of KSE200STSTU at full load?

The KSE200STSTU specifies V_BE(sat) = 2.5 V maximum at I_C = 5 A and I_B = 1 A. Typical values measured under those conditions fall near 2.2–2.4 V, confirming sufficient base drive margin when using 5 V logic or dedicated driver ICs with ≥1 A peak output capability.

Does KSE200STSTU have built-in protection features such as thermal shutdown or overcurrent limiting?

No, the KSE200STSTU is a discrete bipolar transistor without integrated protection circuitry. It relies entirely on external design measures-including base current limiting, heatsinking, current-sense resistors, and SOA-aware drive timing-to prevent secondary breakdown, thermal runaway, or avalanche failure.

Can KSE200STSTU be used in audio amplifier output stages?

Yes, KSE200STSTU has been historically used in Class AB audio output stages up to ~20 W due to its linearity, f_T = 65 MHz, and low distortion at moderate currents. However, modern designs typically prefer complementary pairs with matched h_FE and tighter V_BE tolerances; verify THD and thermal stability in final prototype testing.

KSE200STSTU 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):: 5 A

Voltage - Collector Emitter Breakdown (Max):: 25 V

Vce Saturation (Max) @ Ib, Ic:: 1.8V @ 1A, 5A

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 45 @ 2A, 1V

Power - Max:: 15 W

Frequency - Transition:: 65MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

KSE200STSTU FAQ

1.How can I place an order for KSE200STSTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSE200STSTU 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 KSE200STSTU reliable?

The price and inventory of KSE200STSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSE200STSTU is usually 5 days.

3.What payment methods are accepted for KSE200STSTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSE200STSTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSE200STSTU?

KSE200STSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSE200STSTU 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 KSE200STSTU?

For technical support, including KSE200STSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSE200STSTU requirements.

6.How does Aetrix verify that KSE200STSTU is sourced from the original manufacturer or authorized distributors?

All KSE200STSTU 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 KSE200STSTU meets industry standards.

7.What is the process for return or replacement of KSE200STSTU?

All KSE200STSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSE200STSTU, 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 KSE200STSTU part is unused and in its original packaging.

Return procedure for KSE200STSTU:

1.Submit a request within 90 days.

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

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