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

onsemi KSC945CLTA

Name: KSC945CLTA
Brand: onsemi
SKU: KSC945CLTA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSC945CLTA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: KSC945CLTA.pdf

Description:: TRANS NPN 50V 0.15A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSC945CLTA from onsemi is an NPN epitaxial silicon transistor designed for audio-frequency amplification and high-frequency oscillator circuits, with 60 V collector-base voltage, 300 MHz current gain bandwidth product (f_T), and 250 mW power dissipation in TO-92 package; commonly used in low-power RF stages and signal conditioning in consumer audio equipment.

For engineers reviewing the KSC945CLTA datasheet, pinout, applications, or equivalent options, key selection considerations include its center-collector TO-92 configuration, DC current gain range of 120–240 at 1 mA, V_CE(sat) ≤ 0.3 V at 100 mA/10 mA drive, and noise figure of 4.0 dB at 1 kHz - critical for low-noise preamplifier and oscillator bias design.

Technical Context

This discrete NPN transistor operates with a maximum junction temperature of 150 °C and thermal resistance of 500 °C/W, requiring careful PCB thermal management in continuous-duty applications. Its f_T = 300 MHz (typical) and C_ob = 2.5 pF enable stable operation up to VHF band oscillators when biased per recommended conditions (V_CE = 6 V, I_C = 10 mA).

The device features complementary pairing with KSA733 (PNP), supporting push-pull or differential amplifier topologies. Its center-collector pinout (Pin 1: Emitter, Pin 2: Collector, Pin 3: Base) defines fixed layout constraints for TO-92 footprint routing and thermal path optimization.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CBO	60 V - supports rail-to-rail swing up to 60 V without collector-base breakdown in common-emitter configurations.
f_T	300 MHz (typ) - enables reliable small-signal amplification and oscillator operation up to ~100 MHz fundamental frequency.
h_FE	120–240 @ I_C = 1 mA - provides predictable DC bias stability in linear amplifier stages with moderate gain control.
V_CE(sat)	≤ 0.3 V @ I_C = 100 mA, I_B = 10 mA - ensures low conduction loss in switching or saturated driver applications.
P_D	250 mW @ T_A = 25 °C - limits usable continuous power in ambient-air convection cooling without heatsink.
NF	4.0 dB @ 1 kHz - specifies low-noise performance suitable for microphone preamp input stages.

Pinout & Package

Package: TO-92 (Case 135AN), lead-formed, Pb-free, center-collector configuration. Dimensions: 4.825 mm × 4.76 mm.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for bias network; connects to ground or emitter degeneration resistor in CE amplifier.
2 (Collector)	Current source terminal	Output node for active load or tank circuit connection in oscillator designs; center-pin placement affects lead inductance.
3 (Base)	Control input terminal	Receives forward-bias current to set operating point; requires current-limiting resistor in fixed-bias configurations.

Key Features

Feature	Design Value
High f_T bandwidth	300 MHz typical - supports stable small-signal amplification and LC oscillator operation into VHF range.
Low noise figure	4.0 dB at 1 kHz - enables use in sensitive analog front-end stages where SNR preservation is critical.
Center-collector TO-92	Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base - simplifies layout symmetry in differential pairs and reduces parasitic coupling in RF layouts.
Complementary PNP pair	Matched with KSA733 - allows direct implementation of Class-B or AB output stages without redesign.

Applications

Audio Preamp Stage	RF Local Oscillator
Use Scenario: Low-noise voltage amplification of microphone or line-level signals before ADC sampling. IC Role / Device Role / Timing Role: Discrete NPN transistor configured in common-emitter topology with emitter degeneration. Use Value: 4.0 dB noise figure and h_FE ≥ 120 ensure high-fidelity signal integrity with minimal added noise in battery-powered portable audio.	Use Scenario: Fundamental-frequency oscillator in AM/FM receiver front-end or IF generation circuit. IC Role / Device Role / Timing Role: Active device in Colpitts or Hartley LC tank oscillator configuration. Use Value: 300 MHz f_T and 2.5 pF C_ob support stable oscillation up to 100 MHz with predictable startup and phase noise behavior.
DC Motor Driver (Low-Power)	Signal Level Shifter
Use Scenario: On/off switching of small brushed DC motors in toys, actuators, or instrumentation. IC Role / Device Role / Timing Role: Saturated switch controlling motor current path between supply and ground. Use Value: V_CE(sat) ≤ 0.3 V at 100 mA minimizes power loss and heat generation during continuous conduction.	Use Scenario: Logic-level translation between 3.3 V microcontroller outputs and 5 V peripheral inputs. IC Role / Device Role / Timing Role: Common-emitter level translator with base resistor bias network. Use Value: Guaranteed h_FE ≥ 120 ensures robust saturation even with marginal drive current, reducing propagation delay variation.

Audio Preamp Stage

RF Local Oscillator

Use Scenario: Low-noise voltage amplification of microphone or line-level signals before ADC sampling.

IC Role / Device Role / Timing Role: Discrete NPN transistor configured in common-emitter topology with emitter degeneration.

Use Value: 4.0 dB noise figure and h_FE ≥ 120 ensure high-fidelity signal integrity with minimal added noise in battery-powered portable audio.

Use Scenario: Fundamental-frequency oscillator in AM/FM receiver front-end or IF generation circuit.

IC Role / Device Role / Timing Role: Active device in Colpitts or Hartley LC tank oscillator configuration.

Use Value: 300 MHz f_T and 2.5 pF C_ob support stable oscillation up to 100 MHz with predictable startup and phase noise behavior.

DC Motor Driver (Low-Power)

Signal Level Shifter

Use Scenario: On/off switching of small brushed DC motors in toys, actuators, or instrumentation.

IC Role / Device Role / Timing Role: Saturated switch controlling motor current path between supply and ground.

Use Value: V_CE(sat) ≤ 0.3 V at 100 mA minimizes power loss and heat generation during continuous conduction.

Use Scenario: Logic-level translation between 3.3 V microcontroller outputs and 5 V peripheral inputs.

IC Role / Device Role / Timing Role: Common-emitter level translator with base resistor bias network.

Use Value: Guaranteed h_FE ≥ 120 ensures robust saturation even with marginal drive current, reducing propagation delay variation.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SC1815-Y	f_T = 80 MHz (lower), V_CBO = 60 V, h_FE = 70–700 (wider spread)	Lower bandwidth limits RF use; wider h_FE tolerance increases bias sensitivity.	Acceptable for audio-only amplifiers where f_T margin is not required.
BC547C	f_T = 300 MHz, V_CBO = 50 V (lower), h_FE = 420–800, TO-92 but standard pinout (E-B-C)	Lower breakdown voltage restricts rail voltage headroom; non-center-collector pinout changes PCB layout.	Preferred for new designs needing higher h_FE, but requires layout revision and derating for >50 V operation.

Compared with 2SC1815-Y and BC547C, the KSC945CLTA offers balanced f_T/breakdown/noise performance with center-collector mechanical advantage for RF layout - making it uniquely suited for legacy-compatible oscillator and low-noise preamp designs where pinout and thermal profile are constrained.

Availability

KSC945CLTA is available at Aetrix Electronics and suitable for audio preamplifiers, RF local oscillators, low-power motor drivers, and logic-level shifters requiring stable component supply across industrial and consumer electronics programs.

Supply support for KSC945CLTA 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The KSC945CLTA belongs to onsemi's legacy discrete transistor portfolio, engineered for cost-sensitive, high-reliability analog signal conditioning and switching in consumer electronics and industrial controls.

FAQ

What is the pin configuration of KSC945CLTA?

The KSC945CLTA uses a center-collector TO-92 package with Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base. This configuration is explicitly marked in the onsemi datasheet and differs from standard E-B-C TO-92 layouts. The "C" suffix in KSC945CLTA confirms center-collector orientation, critical for matching legacy board footprints and minimizing lead inductance in RF layouts.

Is KSC945CLTA suitable for RF oscillator applications?

Yes, KSC945CLTA is specifically rated for high-frequency oscillator use, with a typical current gain bandwidth product (f_T) of 300 MHz and low output capacitance (C_ob = 2.5 pF). These parameters, verified in the official onsemi datasheet under V_CE = 6 V, I_C = 10 mA test conditions, support stable Colpitts or Hartley oscillator operation up to 100 MHz fundamental frequency.

What does the "LTA" suffix mean in KSC945CLTA?

The "LTA" suffix in KSC945CLTA indicates lead-free (Pb-free), TO-92 package, tape-and-reel packaging format - consistent with onsemi's ordering nomenclature. It corresponds to Case 135AR mechanical outline and ships in 2,000-unit reels. This suffix distinguishes it from bulk or discontinued variants like KSC945YBU.

How does KSC945CLTA compare to KSA733?

KSC945CLTA is the NPN complement to the PNP KSA733 transistor, sharing matched voltage ratings (V_CBO = 60 V), thermal characteristics, and TO-92 packaging. Their paired h_FE ranges and saturation voltages allow direct use in Class-B amplifier output stages, differential amplifiers, and push-pull oscillator topologies without recalculating bias networks.

What is the maximum safe operating collector current for KSC945CLTA?

The absolute maximum collector current for KSC945CLTA is 150 mA, per the onsemi datasheet Absolute Maximum Ratings table. However, sustained operation above 100 mA requires derating due to its 250 mW power dissipation limit and 500 °C/W junction-to-ambient thermal resistance - exceeding this risks thermal runaway or accelerated degradation.

KSC945CLTA Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 150 mA

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

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 10mA, 100mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 350 @ 1mA, 6V

Power - Max:: 250 mW

Frequency - Transition:: 300MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

KSC945CLTA FAQ

1.How can I place an order for KSC945CLTA through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC945CLTA 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 KSC945CLTA reliable?

The price and inventory of KSC945CLTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC945CLTA is usually 5 days.

3.What payment methods are accepted for KSC945CLTA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC945CLTA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC945CLTA?

KSC945CLTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC945CLTA 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 KSC945CLTA?

For technical support, including KSC945CLTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC945CLTA requirements.

6.How does Aetrix verify that KSC945CLTA is sourced from the original manufacturer or authorized distributors?

All KSC945CLTA 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 KSC945CLTA meets industry standards.

7.What is the process for return or replacement of KSC945CLTA?

All KSC945CLTA units undergo pre-shipment inspection (PSI). If there is an issue with KSC945CLTA, 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 KSC945CLTA part is unused and in its original packaging.

Return procedure for KSC945CLTA:

1.Submit a request within 90 days.

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

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