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onsemi KSC945COTA
- Part No.:
- KSC945COTA
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
KSC945COTA.pdf
- Description:
- TRANS NPN 50V 0.15A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,745
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Product details
Overview
KSC945COTA from onsemi is an NPN epitaxial silicon transistor designed for audio-frequency amplification and high-frequency oscillator circuits, with VCBO = 60 V, fT = 300 MHz (typ), hFE = 120–240, VCE(sat) = 0.15–0.30 V at IC = 100 mA/IB = 10 mA, and TO-92 package with center-collector pinout (Pin 1: Emitter, Pin 2: Collector, Pin 3: Base).
For engineers reviewing the KSC945COTA datasheet, pinout, applications, or equivalent options, this discrete BJT supports low-noise preamplifier stages, RF oscillator tanks, and switching loads up to 150 mA in compact through-hole designs requiring stable gain and thermal performance.
Technical Context
The KSC945COTA operates as a general-purpose NPN bipolar junction transistor optimized for linear amplification and oscillation. Its 300 MHz current-gain bandwidth product enables stable operation up to VHF range, while its 50 V VCEO and 60 V VCBO ratings support moderate-voltage signal paths in consumer audio and timing circuits.
Designed with epitaxial base construction, it delivers consistent hFE across 1–100 mA collector current range and exhibits low output capacitance (Cob = 2.5 pF at VCB = 6 V), supporting fast switching and minimal phase shift in tuned amplifier configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCBO | 60 V - Maximum reverse voltage between collector and base before breakdown; defines safe bias margin in common-base configurations. |
| fT | 300 MHz (typ) - Current-gain bandwidth limit; determines usable frequency range for small-signal amplification and oscillator design. |
| hFE | 120–240 - DC current gain at VCE = 6 V, IC = 1.0 mA; sets base drive requirements for switching or linear gain staging. |
| VCE(sat) | 0.15–0.30 V - Saturation voltage at IC = 100 mA / IB = 10 mA; impacts conduction loss and thermal rise in switching applications. |
| Cob | 2.5 pF (typ) - Output capacitance at VCB = 6 V, f = 1 MHz; influences high-frequency stability and tank circuit Q in oscillator designs. |
| PD | 250 mW - Maximum power dissipation at TA = 25°C; limits continuous current handling without heatsinking in TO-92 package. |
Pinout & Package
Package: TO-92 (Case 135AN), lead-formed, Pb-free, center-collector configuration (Pin 1: Emitter, Pin 2: Collector, Pin 3: Base).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Current exit path for majority carriers | Connected to ground or emitter resistor; polarity defines NPN operation and bias network topology. |
| 2 (Collector) | Current entry path under forward-active bias | Drives load or tank circuit; position as center pin aids thermal symmetry and PCB layout routing. |
| 3 (Base) | Control terminal for carrier injection | Receives bias current to regulate IC; requires stable voltage divider or current source for predictable hFE utilization. |
Key Features
| Feature | Design Value |
|---|---|
| High fT | 300 MHz typical - Enables reliable operation in VHF oscillator and RF amplifier stages without external compensation. |
| Center-collector TO-92 | Pin 2 = Collector - Simplifies PCB trace routing for common-emitter amplifier layouts and improves thermal distribution vs. standard pinout. |
| Low VCE(sat) | 0.15 V min at rated current - Reduces conduction loss and self-heating during pulsed or saturated switching duty cycles. |
| Complementary pairing | Matched to KSA733 PNP - Allows direct use in push-pull, differential pair, or complementary symmetry amplifier topologies. |
Applications
| Audio Preamp Stage | Crystal Oscillator Buffer |
|---|---|
Use Scenario: Low-noise voltage amplification of microphone or line-level signals in portable audio devices. IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration with emitter degeneration. Use Value: 4.0 dB noise figure at 1 kHz and 120–240 hFE enable clean gain without significant SNR degradation. | Use Scenario: Isolating and driving crystal-based Pierce oscillator outputs into digital clock inputs. IC Role / Device Role / Timing Role: High-fT buffer stage maintaining waveform integrity and minimizing loading on resonator. Use Value: 300 MHz fT and 2.5 pF Cob preserve oscillator frequency stability and reduce phase jitter propagation. |
| DC Motor Driver Switch | LED Flasher Oscillator |
Use Scenario: Low-power unidirectional motor control in toys or small actuators using PWM base drive. IC Role / Device Role / Timing Role: Saturated switch controlling motor coil current via collector-emitter path. Use Value: 0.15–0.30 V VCE(sat) limits I²R loss and junction temperature rise at 100 mA continuous load. | Use Scenario: Self-oscillating LED flasher circuit using RC feedback and transistor saturation switching. IC Role / Device Role / Timing Role: Active element in relaxation oscillator with base-emitter capacitance and resistor timing. Use Value: Predictable hFE range and low VBE(sat) ensure consistent flash rate and LED brightness over supply voltage variation. |
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 VCEO = 40 V (vs. 50 V), hFE = 100–300, TO-92 with standard pinout (E-B-C) | Lacks center-collector pinout; lower VCEO reduces margin in 48 V rail interfaces | Select when standard pinout suffices and voltage stress remains below 40 V. |
| KSC1845FTA | fT = 250 MHz (lower), VCEO = 50 V (same), hFE = 120–270, TO-92 with center-collector (E-C-B) | Lower bandwidth limits VHF oscillator use; otherwise compatible in audio and switching roles | Choose when 300 MHz fT is non-critical and higher hFE upper bound is beneficial. |
Compared with 2N3904 and KSC1845FTA, the KSC945COTA provides identical fT and superior VCEO margin while retaining center-collector layout-making it optimal for space-constrained oscillator and amplifier designs where pinout and voltage headroom are jointly critical.
Availability
KSC945COTA is available at Aetrix Electronics and suitable for audio preamplifiers, crystal oscillator buffers, and low-current switching applications requiring stable component supply and legacy-compatible through-hole packaging.
Supply support for KSC945COTA 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, high-performance silicon solutions for automotive, industrial, cloud, medical, and edge applications.
The KSC945COTA belongs to onsemi's legacy small-signal transistor product line, engineered for cost-sensitive, high-volume analog signal conditioning and timing circuits in consumer and industrial electronics.
FAQ
What is the pin configuration of the KSC945COTA?
The KSC945COTA uses a TO-92 package with center-collector pinout: Pin 1 is Emitter, Pin 2 is Collector, and Pin 3 is Base. This configuration differs from standard E-B-C TO-92 transistors and must be verified during PCB layout to avoid functional failure. The "C" suffix in KSC945COTA explicitly denotes this center-collector arrangement per onsemi's marking convention.
Is the KSC945COTA RoHS-compliant and lead-free?
Yes, the KSC945COTA is manufactured in Pb-free (lead-free) TO-92 packaging per onsemi's Case 135AR specification and complies with RoHS Directive 2011/65/EU. The "LF" designation in ordering codes (e.g., KSC945CYTA) confirms lead-free finish, and the device meets JEDEC J-STD-609A Class 1 marking requirements for homogeneous material content.
What is the maximum operating temperature for the KSC945COTA?
The KSC945COTA has a maximum junction temperature (TJ) of 150°C and a storage temperature range of −55°C to +150°C. At ambient temperatures above 25°C, power dissipation must be derated by 2.0 mW/°C, limiting usable PD to ≤200 mW at 50°C ambient. Thermal resistance RθJA is 500°C/W on standard FR-4 PCB land patterns.
Can the KSC945COTA replace the 2N2222A in existing designs?
The KSC945COTA is not a direct replacement for the 2N2222A due to differing pinout (center-collector vs. E-B-C), lower IC rating (150 mA vs. 800 mA), and distinct hFE range. While both are NPN transistors, substituting KSC945COTA requires PCB layout revision and verification of gain, saturation, and thermal margins in the target circuit.
Does the KSC945COTA have documented noise performance for audio use?
Yes, the KSC945COTA specifies a noise figure (NF) of 4.0 dB typical at VCE = 6 V, IC = 0.5 mA, f = 1 kHz, and RS = 500 Ω. This measured value confirms suitability for low-noise preamplifier stages in audio signal chains where SNR preservation is critical, such as electret microphone biasing and line-input buffering.
KSC945COTA 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:
- 70 @ 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
KSC945COTA FAQ
1.How can I place an order for KSC945COTA through Aetrix?
Please submit a Request for Quotation (RFQ) for KSC945COTA 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 KSC945COTA reliable?
The price and inventory of KSC945COTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC945COTA is usually 5 days.
3.What payment methods are accepted for KSC945COTA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC945COTA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSC945COTA?
KSC945COTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSC945COTA 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 KSC945COTA?
For technical support, including KSC945COTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC945COTA requirements.
6.How does Aetrix verify that KSC945COTA is sourced from the original manufacturer or authorized distributors?
All KSC945COTA 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 KSC945COTA meets industry standards.
7.What is the process for return or replacement of KSC945COTA?
All KSC945COTA units undergo pre-shipment inspection (PSI). If there is an issue with KSC945COTA, 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 KSC945COTA part is unused and in its original packaging.
Return procedure for KSC945COTA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
KSC945COTA Tags
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MMBT3906LT1G
onsemi
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Diodes Incorporated
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MMBT3904LT1G
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MMBT3906-7-F
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MMBT2222A-7-F
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BC846BLT1G
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BC847B,215
Nexperia USA Inc.
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SMMBT3904LT1G
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MMBTA06LT1G
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