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onsemi KSC2787OBU
- Part No.:
- KSC2787OBU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 Short Body
- Datasheet:
-
KSC2787OBU.pdf
- Description:
- TRANS NPN 30V 0.05A TO-92S
- Quantity:
- Payment:
- Shipping:
Inventory:3,991
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Product details
Overview
KSC2787OBU from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for RF amplification, mixing, conversion, oscillation, and IF stages in FM/AM receivers. It features VCEO=30V, fT=300MHz (typ), Cob=2.0pF (typ), IC=50mA, and TO-92S package - enabling high-frequency analog signal processing in compact consumer radio front-ends.
For engineers reviewing the KSC2787OBU datasheet, pinout, applications, or equivalent options, key selection criteria include its 300MHz fT, low 2.0pF output capacitance, 30V VCEO rating, DC current gain range of 40–240, and suitability for RF small-signal amplification in portable AM/FM tuners.
Technical Context
This transistor operates as a high-frequency NPN small-signal amplifier with a maximum fT of 300MHz at VCE=6V and IC=1mA, supporting stable gain in VHF band applications. Its low Cob (2.0–2.5pF) and VCE(sat) as low as 0.08V (IC=10mA, IB=1mA) minimize loading and switching loss in oscillator and mixer bias networks.
The device exhibits hFE classification across R/O/Y bins (40–80 / 70–140 / 120–240), allowing gain-matched design in multi-stage RF chains. With TJ=150°C max and TO-92S thermal resistance optimized for low-power RF operation, it sustains reliable performance under continuous small-signal excitation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 30V - supports collector supply up to 30V in RF amplifier and oscillator bias circuits |
| fT | 300MHz (typ) - enables stable small-signal amplification up to VHF band (~100MHz usable gain) |
| Cob | 2.0pF (typ) - minimizes Miller effect and feedback in tuned amplifier and mixer stages |
| hFE | 40–240 - selectable gain bins (R/O/Y) allow matching in multi-transistor RF modules |
| VCE(sat) | 0.08V (min) at IC=10mA/IB=1mA - ensures low-loss saturation in active mixer and switch applications |
| PC | 250mW - defines maximum dissipation in continuous-wave RF operation with adequate heatsinking |
Pinout & Package
Package: TO-92S - 3-lead plastic through-hole package with 1.27mm lead pitch, optimized for RF layout stability and low parasitic inductance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Current sink terminal | Connected to ground or bias network; low-impedance return path for RF signal current |
| 2 (Collector) | Current source terminal | Drives tuned load or next stage; requires proper RF decoupling due to VCEO=30V limit |
| 3 (Base) | Control input terminal | Accepts bias current or RF drive; high-impedance node sensitive to stray capacitance |
Key Features
| Feature | Design Value |
|---|---|
| High fT bandwidth | 300MHz typical - delivers usable gain in FM IF (10.7MHz) and oscillator tank circuits up to ~100MHz |
| Low output capacitance | 2.0pF typical - reduces frequency-dependent phase shift and improves stability in common-emitter RF amps |
| Gain binning support | R/O/Y hFE groups (40–80 / 70–140 / 120–240) - enables consistent gain staging without manual sorting |
| Low VCE(sat) | 0.08V min - minimizes voltage drop in emitter-follower buffers and active mixers operating near ground |
Applications
| FM Radio Front-End Amplifier | AM Band Oscillator |
|---|---|
Use Scenario: Low-noise RF preamplifier stage in portable FM radio tuner modules receiving 88–108MHz signals. IC Role / Device Role / Timing Role: NPN small-signal amplifier configured in common-emitter topology with tuned collector load. Use Value: 300MHz fT and 2.0pF Cob ensure minimal gain roll-off and stable amplification across full FM band. | Use Scenario: Colpitts or Hartley oscillator generating local oscillator signal for AM broadcast band (530–1710kHz) downconversion. IC Role / Device Role / Timing Role: Active device sustaining oscillation via base-collector feedback and LC tank resonance. Use Value: Low VCE(sat) and high hFE enable reliable start-up and low-distortion sinusoidal output at low supply voltages. |
| IF Amplifier Stage | Active Mixer Core |
Use Scenario: Fixed-frequency 10.7MHz intermediate frequency amplifier in superheterodyne FM receivers. IC Role / Device Role / Timing Role: High-gain, narrowband amplifier with ceramic filter coupling and emitter degeneration. Use Value: Tight hFE binning (O/Y) allows predictable gain setting without post-build trimming. | Use Scenario: Single-transistor active mixer converting RF input to IF output using nonlinear junction characteristics. IC Role / Device Role / Timing Role: Switching-mode mixer where base drives RF signal and collector outputs mixed product. Use Value: Fast fT and low Cob preserve mixer conversion efficiency and reduce image response in compact designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN RF transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 2SC3356 | fT=7GHz (typ), VCEO=12V, Cob=0.3pF - higher speed but lower voltage rating | Better suited for UHF/VHF broadband amplifiers; not recommended for 30V supply rails | Select when >500MHz operation required and supply ≤12V; verify bias stability at higher fT |
| MPSH10 | fT=650MHz (typ), VCEO=25V, Cob=1.5pF - higher fT but reduced breakdown margin | Preferred in high-speed switching and wideband IF stages where 25V ceiling is acceptable | Choose for improved bandwidth over KSC2787OBU where VCEO derating to 25V is permissible |
Compared with 2SC3356 and MPSH10, the KSC2787OBU offers superior VCEO margin (30V) and proven stability in AM/FM consumer radio designs, trading peak fT for robustness in cost-sensitive, low-voltage RF front-ends.
Availability
KSC2787OBU is available at Aetrix Electronics and suitable for FM/AM radio receivers, portable audio tuners, and analog RF signal conditioning requiring stable component supply, consistent hFE binning, and TO-92S through-hole compatibility.
Supply support for KSC2787OBU 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 leading designer of discrete semiconductors and power management ICs, acquired by ON Semiconductor in 2016; known for high-reliability analog and RF components.
The KSC2787OBU belongs to Fairchild's legacy RF transistor family targeting consumer audio and broadcast receiver applications, emphasizing gain consistency, low noise, and thermal reliability in compact TO-92S packaging.
FAQ
What is the maximum collector-emitter voltage rating for KSC2787OBU?
The KSC2787OBU has a maximum collector-emitter voltage (VCEO) rating of 30V at Ta=25°C. This rating defines the upper limit for DC or peak AC voltage applied between collector and emitter with base open. Exceeding 30V risks avalanche breakdown; design margins should maintain operation below 27V in production circuits.
Does KSC2787OBU support RF amplification above 100MHz?
Yes, the KSC2787OBU achieves a typical current gain bandwidth product (fT) of 300MHz at VCE=6V and IC=1mA. While usable small-signal gain extends into low-VHF, practical amplification above 100MHz depends on layout, matching networks, and bias stability - verified in FM IF and oscillator applications up to 108MHz.
How is hFE binned for KSC2787OBU, and what do the R/O/Y markings mean?
The KSC2787OBU is binned by DC current gain (hFE) into three classifications: R (40–80), O (70–140), and Y (120–240), measured at VCE=6V and IC=1mA. The suffix "OBU" indicates the O-bin variant. This binning enables predictable gain staging in multi-stage RF amplifiers without post-production calibration.
What is the pin configuration of KSC2787OBU in TO-92S package?
The KSC2787OBU uses standard TO-92S pinout: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base - viewed with flat side facing outward and leads pointing down. This configuration matches JEDEC TO-92S mechanical drawings and ensures correct orientation during manual or automated insertion.
Can KSC2787OBU replace BC547 in RF applications?
No - while both are NPN transistors, the KSC2787OBU is optimized for RF (fT=300MHz, Cob=2.0pF), whereas BC547 is a general-purpose device (fT≈300kHz). Substituting KSC2787OBU for BC547 may cause instability or oscillation in low-frequency circuits due to excessive bandwidth and mismatched capacitance.
KSC2787OBU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 Short Body
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 50 mA
- Voltage - Collector Emitter Breakdown (Max):
- 30 V
- Vce Saturation (Max) @ Ib, Ic:
- 300mV @ 1mA, 10mA
- 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-92S
KSC2787OBU FAQ
1.How can I place an order for KSC2787OBU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSC2787OBU 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 KSC2787OBU reliable?
The price and inventory of KSC2787OBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC2787OBU is usually 5 days.
3.What payment methods are accepted for KSC2787OBU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC2787OBU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSC2787OBU?
KSC2787OBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSC2787OBU 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 KSC2787OBU?
For technical support, including KSC2787OBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC2787OBU requirements.
6.How does Aetrix verify that KSC2787OBU is sourced from the original manufacturer or authorized distributors?
All KSC2787OBU 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 KSC2787OBU meets industry standards.
7.What is the process for return or replacement of KSC2787OBU?
All KSC2787OBU units undergo pre-shipment inspection (PSI). If there is an issue with KSC2787OBU, 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 KSC2787OBU part is unused and in its original packaging.
Return procedure for KSC2787OBU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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