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onsemi KSC945CYBU
- Part No.:
- KSC945CYBU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
KSC945CYBU.pdf
- Description:
- TRANS NPN 50V 0.15A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,300
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Product details
Overview
KSC945CYBU from onsemi 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), 300 MHz current gain bandwidth product (fT), and 250 mW power dissipation in TO-92 package. It serves as a general-purpose RF/AF switching and amplification device in compact consumer and industrial signal-path stages.
For engineers reviewing the KSC945CYBU datasheet, pinout, applications, or equivalent options, key selection criteria include its fT = 300 MHz typical performance, VCBO = 60 V rating, TO-92 leaded package footprint, DC current gain range of 120–240 at IC = 1.0 mA, and suitability for low-noise small-signal amplification where VCE(sat) ≤ 0.30 V at IC = 100 mA.
Technical Context
This discrete NPN transistor operates in linear and switching modes with verified DC current gain (hFE) between 120 and 240 under VCE = 6 V and IC = 1.0 mA conditions. Its 300 MHz fT enables stable operation up to VHF band in oscillator and amplifier topologies.
Thermal resistance is specified at RθJA = 500 °C/W on standard FR-4 PCB (76 mm × 114 mm), and saturation behavior is characterized with VCE(sat) = 0.15–0.30 V at IC = 100 mA / IB = 10 mA, supporting efficient low-voltage switching.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCBO | 60 V - maximum reverse bias before collector-base junction breakdown |
| fT | 300 MHz (typ.) - usable frequency limit for small-signal amplification |
| hFE | 120–240 - DC current gain range enabling predictable biasing at 1 mA collector current |
| VCE(sat) | 0.15–0.30 V - low saturation voltage supports efficient switching in low-voltage logic interfaces |
| PD | 250 mW - continuous power handling on standard FR-4 board without heatsink |
| Cob | 2.5 pF (typ.) - output capacitance limiting high-frequency gain roll-off |
| NF | 4.0 dB - noise figure suitable for low-noise preamplifier stages at 1 kHz |
Pinout & Package
Package: TO-92 (Case 135AN), through-hole, Pb-free, 3-pin plastic package with center-collector configuration (suffix "C" per datasheet).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Emitter | Current sink terminal; connects to ground or low-impedance return path in common-emitter configurations |
| 2 | Base | Control input; requires ~10 mA drive for full saturation at IC = 100 mA |
| 3 | Collector | Current source terminal; center-pin layout simplifies PCB routing in single-transistor amplifier stages |
Key Features
| Feature | Design Value |
|---|---|
| High fT | 300 MHz typical - enables use in VHF oscillators and RF amplifier front-ends up to 100 MHz |
| Low VCE(sat) | 0.15–0.30 V - reduces conduction loss in switching applications powered from 3.3 V or 5 V rails |
| Complementary Pairing | Designed as NPN complement to KSA733 PNP - supports push-pull and differential amplifier designs |
| Low Noise Figure | 4.0 dB at 1 kHz - supports high-fidelity audio preamp stages with minimal signal degradation |
Applications
| Audio Pre-amplifier Stage | RF Local Oscillator |
|---|---|
Use Scenario: Low-noise voltage amplification of microphone or line-level signals prior to ADC sampling. IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter topology with emitter degeneration. Use Value: 4.0 dB noise figure and hFE ≥ 120 ensure SNR preservation in battery-powered portable audio devices. | Use Scenario: Colpitts or Hartley oscillator generating 30–80 MHz local oscillator signals for AM/FM receivers. IC Role / Device Role / Timing Role: Active gain element sustaining oscillation in tuned LC tank circuits. Use Value: 300 MHz fT provides sufficient gain margin for reliable start-up and frequency stability across temperature. |
| DC Motor Driver Switch | Signal Level Shifter |
Use Scenario: Low-side switching of 12 V, <100 mA brushed DC motors in embedded control modules. IC Role / Device Role / Timing Role: Saturated switch controlling motor current path to ground. Use Value: VCE(sat) ≤ 0.30 V minimizes power loss and thermal rise during continuous PWM operation. | Use Scenario: Translating 3.3 V logic outputs to 5 V-compatible inputs in mixed-voltage microcontroller systems. IC Role / Device Role / Timing Role: Common-emitter level translator with fixed bias network. Use Value: hFE ≥ 120 ensures robust saturation with low base drive current, reducing MCU GPIO loading. |
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 |
|---|---|---|---|
| 2N3904 | fT = 300 MHz (same typ.), but VCBO = 60 V and VCEO = 40 V (vs. 50 V for KSC945CYBU); hFE min = 100 | Slightly lower VCEO limits use in higher-voltage collector loads; otherwise interchangeable in AF/oscillator roles | Preferred where legacy 2N3904 footprint compatibility is required and VCEO ≤ 40 V suffices |
| BC547B | fT = 300 MHz (typ.), VCBO = 50 V (vs. 60 V), hFE = 200–450 (wider spread), Cob = 4.5 pF (higher) | Lower VCBO restricts use in higher-voltage oscillator tanks; higher Cob reduces HF gain margin | Acceptable for audio and low-speed switching where 50 V VCBO is adequate and tighter hFE tolerance not critical |
Compared with 2N3904 and BC547B, KSC945CYBU offers superior VCBO (60 V) and lower output capacitance (2.5 pF), making it more suitable for VHF oscillator designs and higher-voltage amplifier stages while maintaining identical fT performance.
Availability
KSC945CYBU is available at Aetrix Electronics and suitable for audio preamplifiers, RF oscillator circuits, low-side motor switching, and logic-level translation requiring stable component supply and long-term sourcing continuity.
Supply support for KSC945CYBU 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 specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The KSC945 series belongs to onsemi's legacy small-signal transistor portfolio, engineered for cost-sensitive, high-volume applications demanding reliable AF/RF amplification and switching performance in TO-92 packaging.
FAQ
What is the pin configuration of the KSC945CYBU?
The KSC945CYBU uses a TO-92 package with center-collector pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. This configuration is confirmed by the "Suffix '−C' Means Center Collector" note in the official onsemi datasheet (Rev. 3, June 2024), and matches mechanical outline CASE 135AN.
Is KSC945CYBU suitable for RF oscillator applications?
Yes, KSC945CYBU is explicitly rated for high-frequency oscillator use per its datasheet Features section. With a typical fT of 300 MHz and low Cob of 2.5 pF, the KSC945CYBU supports stable Colpitts and Hartley oscillator designs up to 80 MHz, especially when biased for optimal gain and phase margin.
What is the maximum collector-emitter voltage rating for KSC945CYBU?
The KSC945CYBU has a VCEO rating of 50 V, defined as the maximum collector-emitter voltage with base open (IB = 0) at TA = 25°C. This value is specified in the Absolute Maximum Ratings table and verified in the Electrical Characteristics section under BVCEO test condition (IC = 10 mA, IB = 0).
Does KSC945CYBU have Pb-free construction?
Yes, KSC945CYBU is manufactured in Pb-free TO-92 packaging per the Ordering Information table, which lists "TO−92 3 (Pb−Free)" and "10,000 Units / Bulk" for this part number. This complies with RoHS Directive 2011/65/EU and onsemi's environmental policy.
How does KSC945CYBU compare to KSC945YTA?
KSC945CYBU and KSC945YTA share identical electrical specifications and TO-92 package, but differ in packaging format and status: KSC945CYBU is bulk-packed (10,000 units), while KSC945YTA is discontinued and shipped in FNFLD tape-and-reel. The "C" suffix in KSC945CYBU confirms center-collector pinout, matching the functional specification of both variants.
KSC945CYBU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- 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:
- 120 @ 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
KSC945CYBU FAQ
1.How can I place an order for KSC945CYBU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSC945CYBU 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 KSC945CYBU reliable?
The price and inventory of KSC945CYBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC945CYBU is usually 5 days.
3.What payment methods are accepted for KSC945CYBU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC945CYBU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSC945CYBU?
KSC945CYBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSC945CYBU 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 KSC945CYBU?
For technical support, including KSC945CYBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC945CYBU requirements.
6.How does Aetrix verify that KSC945CYBU is sourced from the original manufacturer or authorized distributors?
All KSC945CYBU 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 KSC945CYBU meets industry standards.
7.What is the process for return or replacement of KSC945CYBU?
All KSC945CYBU units undergo pre-shipment inspection (PSI). If there is an issue with KSC945CYBU, 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 KSC945CYBU part is unused and in its original packaging.
Return procedure for KSC945CYBU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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