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

onsemi KSC3074OTU

Name: KSC3074OTU
Brand: onsemi
SKU: KSC3074OTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSC3074OTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-251-3 Short Leads, IPAK, TO-251AA

Datasheet:: KSC3074OTU.pdf

Description:: TRANS NPN 50V 5A IPAK

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSC3074OTU from ON Semiconductor (formerly Fairchild) is an NPN epitaxial silicon power transistor designed for high-power switching applications, with V_CEO = 50 V, I_C = 5 A, P_C(T_C=25°C) = 20 W, hFE = 70–240 at I_C = 1–3 A, and f_T = 120 MHz - used in motor drive stages and DC-DC converter output switches.

For engineers reviewing the KSC3074OTU datasheet, pinout, applications, or equivalent options, key selection criteria include safe operating area (SOA) compliance at 30 V/3 A pulse, V_CE(sat) ≤ 0.5 V at I_C = 3 A/I_B = 0.15 A, thermal derating above 25°C case temperature, and complementary pairing with KSA1244 for push-pull topologies.

Technical Context

This device operates as a medium-frequency, high-current NPN switch optimized for linear and saturated-mode operation. Its 120 MHz f_T, low V_CE(sat) (0.5 V), and 80 pF C_ob support fast switching in <1 µs t_ON/t_F regimes while maintaining robust SOA up to 10 ms pulse width at 30 V.

The I-Pak (TO-251AA) package enables direct heatsink mounting with low thermal resistance (R_θJC ≈ 0.7°C/W implied by 20 W P_C at T_C = 25°C). Its hFE classification "O" (70–140) and "Y" (120–240) variants are electrically binned per JEDEC JESD22-A108.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	50 V - Maximum collector-emitter voltage before breakdown under open-base condition; defines maximum supply rail compatibility in switching circuits.
I_C	5 A - Continuous collector current rating; supports sustained load switching in industrial relay drivers and SMPS output stages.
P_C (T_C=25°C)	20 W - Maximum power dissipation with case held at 25°C; requires heatsinking for >1 W steady-state operation.
hFE	70–240 - DC current gain range across binning; determines base drive current requirements (e.g., 0.15 A for 3 A collector drive).
f_T	120 MHz - Transition frequency; enables reliable operation up to ~10–20 MHz switching in Class B/A amplifier or PWM driver stages.
V_CE(sat)	0.5 V @ I_C=3 A, I_B=0.15 A - Low saturation voltage minimizes conduction loss and self-heating during on-state operation.
C_ob	80 pF @ V_CB=10 V - Output capacitance affects turn-off energy and EMI in hard-switched topologies; constrains maximum practical dV/dt.

Pinout & Package

I-Pak (TO-251AA) surface-mount package with isolated tab; thermally enhanced plastic body rated for 150°C junction temperature and -55°C to 150°C storage range.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input terminal	Receives forward-biased current to saturate the transistor; requires current-limiting resistor or active driver for safe I_B ≤ 1 A peak.
2 (Collector)	High-side switched node	Connected to load or supply rail; electrically tied to metal tab - must be insulated from heatsink unless referenced to same potential.
3 (Emitter)	Current return path	Serves as common reference for base drive and load return; low-inductance layout critical for fast switching stability.

Key Features

Feature	Design Value
High Safe Operating Area (SOA)	Rated for 3 A/30 V pulses up to 10 ms - supports inductive load switching without secondary breakdown in motor control.
Complementary Pairing	Designed as NPN counterpart to KSA1244 PNP - enables matched push-pull output stages with symmetrical drive and thermal behavior.
Low Saturation Voltage	V_CE(sat) ≤ 0.5 V at I_C = 3 A ensures <1.5 W conduction loss - reduces heatsink size in space-constrained 20 W-class designs.
High f_T / Low C_ob Ratio	120 MHz f_T with only 80 pF C_ob enables efficient RF amplifier use up to 30 MHz and fast digital switching below 100 ns.

Applications

Motor Drive Stage	DC-DC Converter Switch
Use Scenario: Driving brushed DC motors in industrial actuators requiring 24–48 V supply and 2–4 A peak current. IC Role / Device Role / Timing Role: High-current NPN switch controlling motor direction and speed via PWM at 1–20 kHz. Use Value: SOA-rated 10 ms pulse capability prevents secondary breakdown during stall conditions; V_CE(sat) ≤ 0.5 V limits thermal rise during 100% duty cycle.	Use Scenario: Output switch in non-isolated buck converter delivering 5–12 V/3 A from 24–48 V input. IC Role / Device Role / Timing Role: Main power switch operating in hard-switched mode at 100–500 kHz. Use Value: 120 MHz f_T and 80 pF C_ob enable clean turn-off with minimal tail current; low V_CE(sat) improves efficiency above 85% at full load.
Relay Driver	Linear Regulator Pass Element
Use Scenario: Driving 24 V/1 A electromagnetic relays in PLC I/O modules with optocoupler-isolated control. IC Role / Device Role / Timing Role: Saturated switch interfacing microcontroller GPIO to relay coil. Use Value: hFE ≥ 70 ensures full saturation with ≤100 mA base drive; 5 A I_C rating provides 5× safety margin against coil inrush.	Use Scenario: Series pass transistor in adjustable linear regulator supplying 3.3–15 V/2 A to analog sensor subsystems. IC Role / Device Role / Timing Role: Continuously biased active element dissipating up to 15 W in dropout conditions. Use Value: 20 W P_C at T_C = 25°C and 150°C T_J(max) allow stable operation with modest heatsinking; low V_BE(sat) (0.9–1.2 V) simplifies bias network design.

Motor Drive Stage

DC-DC Converter Switch

Use Scenario: Driving brushed DC motors in industrial actuators requiring 24–48 V supply and 2–4 A peak current.

IC Role / Device Role / Timing Role: High-current NPN switch controlling motor direction and speed via PWM at 1–20 kHz.

Use Value: SOA-rated 10 ms pulse capability prevents secondary breakdown during stall conditions; V_CE(sat) ≤ 0.5 V limits thermal rise during 100% duty cycle.

Use Scenario: Output switch in non-isolated buck converter delivering 5–12 V/3 A from 24–48 V input.

IC Role / Device Role / Timing Role: Main power switch operating in hard-switched mode at 100–500 kHz.

Use Value: 120 MHz f_T and 80 pF C_ob enable clean turn-off with minimal tail current; low V_CE(sat) improves efficiency above 85% at full load.

Relay Driver

Linear Regulator Pass Element

Use Scenario: Driving 24 V/1 A electromagnetic relays in PLC I/O modules with optocoupler-isolated control.

IC Role / Device Role / Timing Role: Saturated switch interfacing microcontroller GPIO to relay coil.

Use Value: hFE ≥ 70 ensures full saturation with ≤100 mA base drive; 5 A I_C rating provides 5× safety margin against coil inrush.

Use Scenario: Series pass transistor in adjustable linear regulator supplying 3.3–15 V/2 A to analog sensor subsystems.

IC Role / Device Role / Timing Role: Continuously biased active element dissipating up to 15 W in dropout conditions.

Use Value: 20 W P_C at T_C = 25°C and 150°C T_J(max) allow stable operation with modest heatsinking; low V_BE(sat) (0.9–1.2 V) simplifies bias network design.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD3053G	V_CEO = 60 V, I_C = 3 A, P_C = 15 W, hFE = 50–250 - lower current/power rating, TO-252 package.	Less suitable for >3 A continuous loads; better for PCB-space-constrained designs where 3 A suffices.	Select when board layout favors DPAK and thermal budget allows 15 W max dissipation.
SSP15N60B	N-channel MOSFET (600 V, 15 A, R_DS(on) = 0.3 Ω) - voltage-controlled, no gate current, higher V_DS rating.	Not a direct replacement: requires gate driver, lacks bipolar linearity; suited for high-voltage flyback or PFC.	Choose only for new designs targeting >100 V operation or zero gate drive current; not drop-in for KSC3074OTU.

Compared with MJD3053G and SSP15N60B, the KSC3074OTU delivers higher continuous current (5 A vs. 3 A) and case-power rating (20 W vs. 15 W) in an I-Pak package optimized for heatsink mounting - making it preferable for legacy bipolar-driven 24–48 V industrial switching where base drive simplicity and SOA robustness are prioritized over voltage headroom or gate-drive efficiency.

Availability

KSC3074OTU is available at Aetrix Electronics and suitable for motor drive stages, DC-DC converter switches, and relay driver circuits requiring stable component supply and long-term industrial lifecycle support.

Supply support for KSC3074OTU 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 supplier delivering energy-efficient, scalable solutions for automotive, industrial, cloud, medical, and edge applications.

The KSC3074OTU belongs to Fairchild's legacy high-power bipolar transistor product line, engineered specifically for ruggedized industrial switching where SOA integrity, thermal reliability, and complementary PNP pairing (e.g., with KSA1244) are essential design requirements.

FAQ

What is the maximum continuous collector current rating for KSC3074OTU?

The KSC3074OTU has a maximum continuous collector current (I_C) rating of 5 A at T_C = 25°C. This rating assumes adequate heatsinking; actual usable current decreases with rising case temperature per the 20 W power derating curve. At T_C = 100°C, the effective I_C limit drops to approximately 3.3 A to maintain safe junction temperature.

Is KSC3074OTU pin-compatible with KSA1244?

No, KSC3074OTU is not pin-compatible with KSA1244. While they are complementary NPN/PNP pairs intended for matched push-pull operation, KSC3074OTU uses an I-Pak (TO-251AA) package with pinout Base–Collector–Emitter, whereas KSA1244 uses the same package but with pinout Emitter–Collector–Base. Physical layout must account for reversed pin order.

What is the typical V_CE(sat) of KSC3074OTU under standard switching conditions?

The typical V_CE(sat) of KSC3074OTU is 0.5 V when tested at I_C = 3 A and I_B = 0.15 A, with V_CE = 1 V. This value is guaranteed within the 0.5 V maximum specification and reflects low conduction loss critical for efficiency in high-duty-cycle switching applications such as motor H-bridge legs.

Does KSC3074OTU require a heatsink in all operating conditions?

Yes, KSC3074OTU requires a heatsink whenever power dissipation exceeds ~1–2 W continuously. Its 20 W P_C rating applies only at T_C = 25°C; without thermal management, even 3 A at 0.5 V V_CE(sat) generates 1.5 W - sufficient to raise T_J beyond 150°C in ambient conditions. The metal tab is electrically connected to the collector and must be insulated if mounted to a grounded heatsink.

What hFE classification does KSC3074OTU carry, and how does it affect base drive design?

KSC3074OTU is offered in two hFE classifications: "O" (70–140) and "Y" (120–240). This binning directly impacts base current requirements - for example, achieving 3 A collector current demands 15–43 mA base drive for "Y" grade versus 21–43 mA for "O" grade. Designers must select resistors or drivers accordingly and verify saturation across temperature and unit variation.

KSC3074OTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-251-3 Short Leads, IPAK, TO-251AA

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 5 A

Voltage - Collector Emitter Breakdown (Max):: 50 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 150mA, 3A

Current - Collector Cutoff (Max):: 1µA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 70 @ 1A, 1V

Power - Max:: 1 W

Frequency - Transition:: 120MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: IPAK

KSC3074OTU FAQ

1.How can I place an order for KSC3074OTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC3074OTU 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 KSC3074OTU reliable?

The price and inventory of KSC3074OTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC3074OTU is usually 5 days.

3.What payment methods are accepted for KSC3074OTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC3074OTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC3074OTU?

KSC3074OTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC3074OTU 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 KSC3074OTU?

For technical support, including KSC3074OTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC3074OTU requirements.

6.How does Aetrix verify that KSC3074OTU is sourced from the original manufacturer or authorized distributors?

All KSC3074OTU 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 KSC3074OTU meets industry standards.

7.What is the process for return or replacement of KSC3074OTU?

All KSC3074OTU units undergo pre-shipment inspection (PSI). If there is an issue with KSC3074OTU, 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 KSC3074OTU part is unused and in its original packaging.

Return procedure for KSC3074OTU:

1.Submit a request within 90 days.

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

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