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

onsemi KSA1244YTU

Name: KSA1244YTU
Brand: onsemi
SKU: KSA1244YTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSA1244YTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSA1244YTU.pdf

Description:: TRANS PNP 50V 5A IPAK

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSA1244YTU from Fairchild Semiconductor is a PNP epitaxial silicon transistor designed for high-current switching applications, with −50 V V_CEO, −5 A I_C, 20 W P_C (T_C=25°C), h_FE of 120–240 at I_C = −3 A, and V_CE(sat) = −0.5 V at I_C = −3 A / I_B = −0.15 A - used in DC-DC converter output stages and relay drivers.

For engineers reviewing the KSA1244YTU datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed h_FE classification (Y-grade: 120–240), low saturation voltage under high current, thermal performance at T_C, safe operating area (SOA) limits, and complementary pairing with KSC3074 in push-pull configurations.

Technical Context

This PNP bipolar junction transistor operates in linear or saturated switching mode with fixed emitter-base and collector-base breakdown limits (−5 V V_EBO, −60 V V_CBO). Its f_T of 60 MHz supports medium-speed switching up to ~100 kHz duty-cycle operation.

The device uses an I-Pak (TO-251AA) surface-mount package with exposed drain pad for thermal conduction, rated for 150°C junction temperature and −55°C to 150°C storage range. Safe operating area curves define pulse and DC current-voltage boundaries under varying case temperatures.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−50 V - maximum allowable collector-emitter voltage before avalanche breakdown under open-base condition
I_C	−5 A - continuous DC collector current rating at T_C = 25°C
P_C (T_C)	20 W - maximum power dissipation with heatsink at case temperature 25°C
h_FE (Y-grade)	120–240 - guaranteed DC current gain range at V_CE = −1 V, I_C = −3 A
V_CE(sat)	−0.5 V - collector-emitter voltage drop at I_C = −3 A and I_B = −0.15 A, defining conduction loss in switch mode
f_T	60 MHz - transition frequency indicating usable bandwidth for small-signal amplification or fast switching
t_ON/t_F	0.1 µs / 0.1 µs - turn-on and fall times under specified resistive load and drive conditions

Pinout & Package

The KSA1244YTU is housed in an I-Pak (TO-251AA) surface-mount package with integrated heat slug; dimensions are 9.30 × 16.10 × 6.10 mm (L×W×H), featuring gull-wing leads and thermally enhanced backside metal pad.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control electrode	Receives forward-biased base current to enable conduction; requires −0.15 A for full saturation at −3 A collector load
2 (Collector)	Current sink terminal	Connected to higher potential (e.g., supply rail); carries full load current when saturated; electrically tied to heat slug
3 (Emitter)	Current source terminal	Typically tied to load or ground return path; provides reference for base-emitter biasing and defines V_BE(sat) behavior

Key Features

Feature	Design Value
Low V_CE(sat)	−0.5 V at −3 A ensures <0.15 W conduction loss, reducing thermal stress in high-duty-cycle switching
High h_FE Y-classification	120–240 gain range enables reliable saturation with moderate base drive, easing gate driver design
Complementary pairing	Designed as PNP counterpart to NPN KSC3074, enabling matched push-pull or H-bridge output stages
Robust SOA	Rated for 5 A DC and pulsed operation up to 10 ms within defined V_CE–I_C boundaries, supporting inductive load handling

Applications

DC-DC Converter Output Stage	Industrial Relay Driver
Use Scenario: High-efficiency buck converter output switch driving 3–5 A loads at 20–100 kHz switching frequency. IC Role / Device Role / Timing Role: PNP power switch controlling current flow from input rail to inductor; operates in saturated on/off states. Use Value: Low −0.5 V V_CE(sat) minimizes conduction loss; 20 W T_C-rated dissipation supports heatsink-free operation at ≤2 A average load.	Use Scenario: Driving 24 V/2 A electromagnetic relays in PLC I/O modules with optocoupler-isolated base control. IC Role / Device Role / Timing Role: High-current interface transistor translating logic-level signals into relay coil actuation current. Use Value: Guaranteed h_FE ≥120 ensures full saturation with ≤150 mA base drive; −50 V V_CEO withstands relay coil flyback transients.
Motor Control Half-Bridge	Linear Regulator Pass Element
Use Scenario: Upper-side switch in discrete PNP-NPN half-bridge for 12 V brushed DC motor control (≤5 A peak). IC Role / Device Role / Timing Role: High-side current sink switching motor phase voltage; paired with KSC3074 on low side. Use Value: Matched gain and saturation characteristics with KSC3074 simplify complementary drive design; SOA supports 5 A inductive kickback.	Use Scenario: Series pass transistor in adjustable 3 A linear regulator supplying FPGA core voltage (1.2–3.3 V). IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output by dissipating excess input-output differential. Use Value: 20 W T_C rating allows stable operation at 2.5 A with 5 V dropout; −50 V V_CEO accommodates input up to 45 V.

DC-DC Converter Output Stage

Industrial Relay Driver

Use Scenario: High-efficiency buck converter output switch driving 3–5 A loads at 20–100 kHz switching frequency.

IC Role / Device Role / Timing Role: PNP power switch controlling current flow from input rail to inductor; operates in saturated on/off states.

Use Value: Low −0.5 V V_CE(sat) minimizes conduction loss; 20 W T_C-rated dissipation supports heatsink-free operation at ≤2 A average load.

Use Scenario: Driving 24 V/2 A electromagnetic relays in PLC I/O modules with optocoupler-isolated base control.

IC Role / Device Role / Timing Role: High-current interface transistor translating logic-level signals into relay coil actuation current.

Use Value: Guaranteed h_FE ≥120 ensures full saturation with ≤150 mA base drive; −50 V V_CEO withstands relay coil flyback transients.

Motor Control Half-Bridge

Linear Regulator Pass Element

Use Scenario: Upper-side switch in discrete PNP-NPN half-bridge for 12 V brushed DC motor control (≤5 A peak).

IC Role / Device Role / Timing Role: High-side current sink switching motor phase voltage; paired with KSC3074 on low side.

Use Value: Matched gain and saturation characteristics with KSC3074 simplify complementary drive design; SOA supports 5 A inductive kickback.

Use Scenario: Series pass transistor in adjustable 3 A linear regulator supplying FPGA core voltage (1.2–3.3 V).

IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output by dissipating excess input-output differential.

Use Value: 20 W T_C rating allows stable operation at 2.5 A with 5 V dropout; −50 V V_CEO accommodates input up to 45 V.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-current PNP switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD127G	−80 V V_CEO, −8 A I_C, 30 W P_C, h_FE 25–250 (unbinned), TO-252 package	Higher voltage/current ratings but wider h_FE spread; larger footprint than I-Pak	Preferred where higher breakdown margin or higher current headroom is required; requires PCB layout revision
BCP53-16	−45 V V_CEO, −1.5 A I_C, 1.5 W P_C, SOT-223 package, h_FE 100–250	Lower power and current capability; not suitable for >2 A continuous loads	Only viable for low-power signal switching or pre-driver stages; not a functional replacement for KSA1244YTU's 5 A role

Compared with MJD127G and BCP53-16, the KSA1244YTU offers optimal balance of 5 A current handling, −50 V rating, and Y-grade h_FE consistency in compact I-Pak, making it preferred for space-constrained 3–5 A switching where thermal management via case mounting is feasible.

Availability

KSA1244YTU is available at Aetrix Electronics and suitable for industrial motor drives, DC-DC converters, and relay interface circuits requiring stable component supply, consistent Y-grade h_FE binning, and proven thermal performance in I-Pak packaging.

Supply support for KSA1244YTU 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016.

The KSA1244YTU belongs to Fairchild's high-current PNP transistor family engineered for robust switching in industrial power conversion and control systems, emphasizing low saturation voltage and thermal reliability.

FAQ

What is the h_FE classification for KSA1244YTU?

The KSA1244YTU is Y-classified, meaning its DC current gain (h_FE) is guaranteed between 120 and 240 when measured at V_CE = −1 V and I_C = −3 A. This tight binning ensures predictable base drive requirements in production designs using the KSA1244YTU.

Is KSA1244YTU pin-compatible with KSC3074?

No - KSA1244YTU (PNP) and KSC3074 (NPN) are complementary in function but not pin-compatible; KSA1244YTU has Base–Collector–Emitter pinout (1–2–3), while KSC3074 uses Emitter–Collector–Base (1–2–3). Their pairing requires intentional PCB layout for push-pull topology, not drop-in substitution.

What package type does KSA1244YTU use?

KSA1244YTU uses the I-Pak (TO-251AA) surface-mount package, featuring three gull-wing leads and an exposed thermal pad on the underside. Its mechanical outline measures 9.30 × 16.10 × 6.10 mm, and the collector is internally connected to the heat slug for efficient thermal transfer to the PCB.

Can KSA1244YTU be used in linear regulator applications?

Yes - the KSA1244YTU supports linear regulation with up to 20 W power dissipation at T_C = 25°C and a −50 V V_CEO rating, enabling use as a series pass element in adjustable 3 A regulators. Thermal design must ensure case temperature remains within derating limits per Figure 6 in the KSA1244YTU datasheet.

What is the maximum safe operating collector current for KSA1244YTU?

The KSA1244YTU supports −5 A continuous collector current at T_C = 25°C. At higher case temperatures, current must be reduced per the derating curve: e.g., at T_C = 100°C, max I_C drops to approximately −3.2 A. Pulse operation up to 10 ms allows higher peak currents within the SOA boundary shown in Figure 5 of the KSA1244YTU datasheet.

KSA1244YTU 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:: PNP

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:: 120 @ 1A, 1V

Power - Max:: 1 W

Frequency - Transition:: 60MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: IPAK

KSA1244YTU FAQ

1.How can I place an order for KSA1244YTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSA1244YTU 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 KSA1244YTU reliable?

The price and inventory of KSA1244YTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSA1244YTU is usually 5 days.

3.What payment methods are accepted for KSA1244YTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSA1244YTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSA1244YTU?

KSA1244YTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSA1244YTU 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 KSA1244YTU?

For technical support, including KSA1244YTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSA1244YTU requirements.

6.How does Aetrix verify that KSA1244YTU is sourced from the original manufacturer or authorized distributors?

All KSA1244YTU 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 KSA1244YTU meets industry standards.

7.What is the process for return or replacement of KSA1244YTU?

All KSA1244YTU units undergo pre-shipment inspection (PSI). If there is an issue with KSA1244YTU, 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 KSA1244YTU part is unused and in its original packaging.

Return procedure for KSA1244YTU:

1.Submit a request within 90 days.

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

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