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onsemi KSC945CGTA
- Part No.:
- KSC945CGTA
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
KSC945CGTA.pdf
- Description:
- TRANS NPN 50V 0.15A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,604
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Product details
Overview
KSC945CGTA from ON Semiconductor (formerly Fairchild) is an NPN epitaxial silicon transistor designed for audio-frequency amplification and high-frequency oscillator circuits, with a 60 V collector-base breakdown voltage (VCBO), 50 V collector-emitter breakdown voltage (VCEO), and 300 MHz current gain bandwidth product (fT). It operates up to 150 mA collector current and supports stable small-signal gain in portable audio preamps and RF local oscillators.
For engineers reviewing the KSC945CGTA datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92 package configuration, hFE classification range (200–400 for 'G' grade), low VCE(sat) of 0.15–0.30 V at IC = 100 mA/IB = 10 mA, and noise figure of 4.0 dB at 1 kHz - all critical for low-distortion analog front-ends and battery-powered signal generation.
Technical Context
This transistor employs epitaxial base construction to achieve high fT and low noise, enabling reliable operation in both linear amplification and switching modes. Its DC current gain (hFE) is specified across five classifications (R/O/Y/G/L), with KSC945CGTA falling in the 'G' group (hFE = 200–400 at VCE = 6 V, IC = 1.0 mA), ensuring predictable bias stability in discrete amplifier stages.
The device features low output capacitance (Cob = 2.5 pF at VCB = 6 V, f = 1 MHz) and tight saturation voltage control, supporting efficient operation in tuned RF oscillator tanks and Class-A audio driver stages where parasitic capacitance and conduction loss directly impact frequency accuracy and THD.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCBO | 60 V - maximum reverse-biased collector-base voltage before breakdown; sets safe operating margin for bootstrap and cascode configurations |
| VCEO | 50 V - maximum collector-emitter voltage under open-base condition; defines usable supply rail headroom in common-emitter amps |
| IC(max) | 150 mA - continuous collector current limit; determines drive capability for small-signal loads like relay coils or LED drivers |
| fT | 300 MHz (typical) - unity-gain frequency; enables stable amplification up to VHF band in oscillator and RF buffer designs |
| hFE (G-grade) | 200–400 - DC current gain range at VCE = 6 V, IC = 1.0 mA; ensures consistent bias point setting without manual trimming |
| VCE(sat) | 0.15–0.30 V at IC = 100 mA / IB = 10 mA - low saturation voltage minimizes power loss and thermal rise in switching applications |
| Noise Figure | 4.0 dB at f = 1 kHz, RS = 500 Ω - quantifies input-referred noise in audio preamp stages; supports <1% THD in line-level circuits |
Pinout & Package
Package: TO-92 3L (plastic, through-hole), with center-collector pinout per suffix "-C": Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base.
| 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 amplifiers |
| 2 (Collector) | Current source terminal | Output node for active load or tank circuit connection; requires proper decoupling in RF oscillator layouts |
| 3 (Base) | Control input terminal | Receives forward-bias current to set operating point; sensitive to PCB trace inductance above 10 MHz |
Key Features
| Feature | Design Value |
|---|---|
| High fT (300 MHz) | Enables stable small-signal amplification and oscillation up to 100 MHz without external neutralization |
| G-grade hFE (200–400) | Reduces production binning variance in batch-manufactured audio gain stages and oscillator frequency drift |
| Low Cob (2.5 pF) | Minimizes Miller effect in high-gain CE stages, preserving bandwidth and reducing phase shift in feedback loops |
| Low VCE(sat) (0.15–0.30 V) | Lowers conduction loss and self-heating in battery-powered switching applications such as LED flash drivers |
| Complementary pairing with KSA733 | Supports discrete push-pull output stages in Class-B audio amplifiers with matched thermal and gain characteristics |
Applications
| Portable Audio Preamp | RF Local Oscillator |
|---|---|
Use Scenario: Low-noise voltage amplification of microphone or line-level signals in handheld recorders and Bluetooth speakers. IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter configuration with emitter degeneration. Use Value: 4.0 dB noise figure and G-grade hFE ensure consistent gain and minimal hiss across production units without trimming. | Use Scenario: Fundamental-mode LC oscillator generating 27–108 MHz carrier signals for AM/FM transmitter modules. IC Role / Device Role / Timing Role: Active device in Colpitts or Hartley topology providing loop gain and phase shift compensation. Use Value: 300 MHz fT and 2.5 pF Cob enable stable oscillation with minimal tuning sensitivity to layout parasitics. |
| Discrete LED Flash Driver | Industrial Sensor Signal Conditioning |
Use Scenario: Pulsed current source for white LED strobes in security cameras and machine vision lighting systems. IC Role / Device Role / Timing Role: Switching transistor controlled by microcontroller GPIO with base current limiting. Use Value: 0.15–0.30 V VCE(sat) limits power dissipation to <15 mW at 100 mA, avoiding thermal derating in compact enclosures. | Use Scenario: Amplification of millivolt-level thermocouple or strain gauge outputs in PLC analog input modules. IC Role / Device Role / Timing Role: First-stage DC-coupled amplifier with precision bias network and low-drift hFE. Use Value: Tight hFE spread (200–400) and 0.1 μA ICBO support stable offset performance over –40°C to +85°C ambient. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN small-signal transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC547C | Lower fT (300 MHz max, but typically 150–250 MHz); hFE = 420–800 (C-grade); same TO-92 package, but pinout is E-B-C (not E-C-B) | Not suitable for direct replacement in KSC945CGTA's center-collector oscillator layouts without PCB revision | Select only if redesigning base bias network and verifying layout compatibility with E-B-C orientation |
| MPSA18 | Higher VCBO (60 V same), but higher VCEO (60 V vs. 50 V); fT = 600 MHz (typical); hFE = 100–300 (standard grade) | Better suited for higher-voltage RF amplifiers but lacks G-grade hFE consistency for precision audio gain blocks | Prefer when extended voltage headroom or wider bandwidth is required, accepting broader hFE distribution |
Compared with BC547C and MPSA18, KSC945CGTA offers guaranteed center-collector TO-92 pinout, tighter hFE grouping (200–400), and validated 300 MHz fT performance - making it optimal for cost-sensitive, high-volume oscillator and preamp designs where layout reuse and binning control are critical.
Availability
KSC945CGTA is available at Aetrix Electronics and suitable for portable audio preamps, RF local oscillators, discrete LED flash drivers, and industrial sensor signal conditioning requiring stable component supply and long-term manufacturability.
Supply support for KSC945CGTA 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 (formerly Fairchild Semiconductor) is a global supplier of energy-efficient semiconductor components, specializing in power management, analog, and discrete devices for automotive, industrial, and consumer markets.
The KSC945CGTA belongs to ON Semiconductor's legacy small-signal transistor portfolio, originally developed for high-fidelity audio and RF timing applications where gain consistency, noise performance, and thermal reliability are essential.
FAQ
What is the pin configuration of KSC945CGTA?
KSC945CGTA uses a TO-92 3L package with center-collector pinout: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base. This configuration is explicitly defined by the "-C" suffix in the part number and confirmed in the Fairchild KSC945 Rev. 1.1.0 datasheet. The KSC945CGTA pinout differs from standard E-B-C arrangements, so PCB layout must reflect this ordering to avoid functional failure.
What does the 'G' in KSC945CGTA indicate?
The 'G' in KSC945CGTA denotes the hFE classification grade, specifying a DC current gain range of 200–400 at VCE = 6 V and IC = 1.0 mA. This grading ensures tighter parametric consistency than lower grades (e.g., 'Y' = 120–240) and supports repeatable biasing in production audio and oscillator circuits without manual adjustment. The KSC945CGTA grade is documented in the official ordering information table and electrical characteristics section.
Is KSC945CGTA suitable for RF oscillator applications?
Yes, KSC945CGTA is specifically characterized for high-frequency oscillator use, with a typical fT of 300 MHz and low output capacitance (Cob = 2.5 pF). Its epitaxial structure and optimized doping profile support stable fundamental-mode oscillation in Colpitts and Hartley topologies up to ~100 MHz. The KSC945CGTA datasheet explicitly lists "High-Frequency OSC" as a primary feature, confirming its suitability beyond general-purpose amplification.
How does KSC945CGTA compare to KSC945YTA?
KSC945CGTA and KSC945YTA share identical TO-92 packaging and absolute maximum ratings, but differ in hFE grading: KSC945CGTA is 'G' grade (200–400), while KSC945YTA is 'Y' grade (120–240). Both are supplied in ammo packaging, but KSC945CGTA provides higher and tighter gain consistency - critical for low-distortion audio stages and frequency-stable oscillators where gain variation affects THD and tuning repeatability. The KSC945CGTA specification is verified in the hFE classification table of the official datasheet.
What is the maximum power dissipation for KSC945CGTA?
KSC945CGTA has a maximum power dissipation (PD) of 250 mW at TA = 25°C, with a derating factor of 2.0 mW/°C above that temperature. This value is defined under standard FR-4 PCB conditions (76 mm × 114 mm × 1.57 mm) and reflects thermal resistance RθJA = 500 °C/W. Exceeding this limit risks junction temperature exceeding 150°C, potentially degrading hFE or causing permanent damage. The KSC945CGTA thermal characteristics are fully specified in the Thermal Characteristics section of the datasheet.
KSC945CGTA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Packaging:
- Bulk
- 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:
- 200 @ 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
KSC945CGTA FAQ
1.How can I place an order for KSC945CGTA through Aetrix?
Please submit a Request for Quotation (RFQ) for KSC945CGTA 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 KSC945CGTA reliable?
The price and inventory of KSC945CGTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC945CGTA is usually 5 days.
3.What payment methods are accepted for KSC945CGTA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC945CGTA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSC945CGTA?
KSC945CGTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSC945CGTA 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 KSC945CGTA?
For technical support, including KSC945CGTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC945CGTA requirements.
6.How does Aetrix verify that KSC945CGTA is sourced from the original manufacturer or authorized distributors?
All KSC945CGTA 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 KSC945CGTA meets industry standards.
7.What is the process for return or replacement of KSC945CGTA?
All KSC945CGTA units undergo pre-shipment inspection (PSI). If there is an issue with KSC945CGTA, 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 KSC945CGTA part is unused and in its original packaging.
Return procedure for KSC945CGTA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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