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

onsemi KSC2786RTA

Name: KSC2786RTA
Brand: onsemi
SKU: KSC2786RTA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSC2786RTA

Manufacturer:: onsemi

Category:: Bipolar RF Transistors

Package:: TO-226-3, TO-92-3 Short Body

Datasheet:: KSC2786RTA.pdf

Description:: RF TRANS NPN 20V 600MHZ TO92S

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSC2786RTA from Fairchild Semiconductor is an NPN epitaxial silicon RF transistor optimized for high-frequency amplification in TV PIF, FM tuner RF amplifier, mixer, and oscillator circuits. It delivers f_T = 600 MHz (typ), GPE = 22 dB at 100 MHz, V_CE(sat) = 0.3 V max at I_C = 10 mA/I_B = 1 mA, and noise figure NF = 5.0 dB at 100 MHz with R_S = 50 Ω.

For engineers reviewing the KSC2786RTA datasheet, pinout, applications, or equivalent options, key selection criteria include its 600 MHz f_T, low 0.3 V saturation voltage, 22 dB power gain at 100 MHz, 1.2 pF output capacitance, and TO-92S package suitability for compact RF stage layouts.

Technical Context

The KSC2786RTA operates as a high-gain, low-noise NPN RF amplifier with f_T up to 600 MHz and power gain of 22 dB at 100 MHz. Its low V_CE(sat) (0.1–0.3 V) and small Cob (1.2 pF) support efficient switching and wideband linear amplification in tuned RF stages.

Designed for bias stability in V_CE = 6 V, I_C = 1 mA conditions, it exhibits h_FE ranging 40–240 (classified R/O/Y), V_BE(on) = 0.72 V, and junction temperature rating up to 150°C - enabling reliable operation in consumer RF front-ends.

Key Specifications

Parameter	Value and Actual Design Meaning
f_T	600 MHz typical - enables stable amplification up to UHF band in TV PIF and FM tuner applications
GPE	22 dB at 100 MHz - provides sufficient gain margin for low-level RF signal boosting without external matching complexity
V_CE(sat)	0.3 V max at I_C=10 mA/I_B=1 mA - minimizes power loss and thermal rise in saturated switching or Class-A amplifier modes
Cob	1.2 pF at V_CB=6 V - reduces Miller effect and supports wideband impedance matching in 50 Ω systems
NF	5.0 dB at 100 MHz, R_S=50 Ω - ensures acceptable signal-to-noise ratio in sensitive RF receiver front-ends
h_FE	40–240 (Y-class: 120–240) - allows predictable DC bias design across production lots with defined gain spread
P_C	250 mW - sets maximum continuous dissipation limit for thermal design in TO-92S plastic package

Pinout & Package

Package: TO-92S (3-lead plastic through-hole), lead spacing 1.27 mm, body height 4.00 mm, total length 14.47 mm - optimized for manual and automated insertion in compact RF PCBs.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or AC-coupled reference; low-impedance path for majority carriers in common-base/common-emitter configurations
2 (Collector)	Output current source	Drives tuned load or next stage; requires DC blocking and impedance matching per RF layout best practices
3 (Base)	Control input	Receives bias current or RF drive; high-impedance node requiring stable DC path and minimal parasitic coupling

Key Features

Feature	Design Value
High f_T	600 MHz typical - supports stable amplification beyond VHF into low-UHF bands without gain roll-off
Low noise figure	5.0 dB at 100 MHz - preserves SNR in weak-signal reception paths such as FM tuner RF amplifiers
High power gain	22 dB at 100 MHz - reduces need for cascaded stages in cost-sensitive consumer RF designs
Low saturation voltage	V_CE(sat) ≤ 0.3 V - improves efficiency and thermal headroom in battery-powered or space-constrained RF modules
TO-92S footprint	Standardized 3-pin through-hole package - enables drop-in replacement and compatibility with legacy assembly processes

Applications

TV PIF Amplifier	FM Tuner RF Amplifier
Use Scenario: Amplifies intermediate frequency signals (45.75 MHz for NTSC) after mixer stage in analog television receivers. IC Role / Device Role / Timing Role: NPN RF amplifier operating in Class-A configuration with fixed emitter degeneration for linearity. Use Value: Delivers >20 dB gain with <5 dB noise figure, meeting IF stage SNR requirements while maintaining stability under varying supply conditions.	Use Scenario: Boosts weak FM broadcast band signals (88–108 MHz) prior to mixing in portable or automotive FM tuners. IC Role / Device Role / Timing Role: Low-noise RF preamplifier biased at V_CE = 6 V, I_C = 1 mA for optimal f_T and NF trade-off. Use Value: Achieves 22 dB power gain and 5.0 dB NF at 100 MHz, enabling robust reception in low-S/N environments without added filtering complexity.
Mixer Stage	Oscillator Core
Use Scenario: Serves as active element in balanced or unbalanced passive mixer topologies in TV and radio front-ends. IC Role / Device Role / Timing Role: Switching/transconductance device modulating LO and RF inputs; leverages high f_T and low C_ob for broadband mixing. Use Value: 1.2 pF Cob and 600 MHz f_T minimize conversion loss and image rejection degradation across VHF/UHF bands.	Use Scenario: Forms the active device in Colpitts or Hartley LC oscillators for local oscillator generation in TV and FM systems. IC Role / Device Role / Timing Role: Sustains oscillation via controlled negative resistance; benefits from high h_FE and low V_CE(sat) for start-up reliability. Use Value: Stable oscillation achieved with Y-class h_FE (120–240) and 0.3 V V_CE(sat), reducing phase noise contribution and improving frequency stability.

TV PIF Amplifier

FM Tuner RF Amplifier

Use Scenario: Amplifies intermediate frequency signals (45.75 MHz for NTSC) after mixer stage in analog television receivers.

IC Role / Device Role / Timing Role: NPN RF amplifier operating in Class-A configuration with fixed emitter degeneration for linearity.

Use Value: Delivers >20 dB gain with <5 dB noise figure, meeting IF stage SNR requirements while maintaining stability under varying supply conditions.

Use Scenario: Boosts weak FM broadcast band signals (88–108 MHz) prior to mixing in portable or automotive FM tuners.

IC Role / Device Role / Timing Role: Low-noise RF preamplifier biased at V_CE = 6 V, I_C = 1 mA for optimal f_T and NF trade-off.

Use Value: Achieves 22 dB power gain and 5.0 dB NF at 100 MHz, enabling robust reception in low-S/N environments without added filtering complexity.

Mixer Stage

Oscillator Core

Use Scenario: Serves as active element in balanced or unbalanced passive mixer topologies in TV and radio front-ends.

IC Role / Device Role / Timing Role: Switching/transconductance device modulating LO and RF inputs; leverages high f_T and low C_ob for broadband mixing.

Use Value: 1.2 pF Cob and 600 MHz f_T minimize conversion loss and image rejection degradation across VHF/UHF bands.

Use Scenario: Forms the active device in Colpitts or Hartley LC oscillators for local oscillator generation in TV and FM systems.

IC Role / Device Role / Timing Role: Sustains oscillation via controlled negative resistance; benefits from high h_FE and low V_CE(sat) for start-up reliability.

Use Value: Stable oscillation achieved with Y-class h_FE (120–240) and 0.3 V V_CE(sat), reducing phase noise contribution and improving frequency stability.

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	f_T = 7 GHz (vs. 600 MHz); higher V_CEO = 20 V; lower NF = 1.1 dB at 1 GHz	Targeted at 1–3 GHz cellular/WiFi front-ends, not optimized for sub-200 MHz TV/FM bands	Select only if operating above 500 MHz with strict NF requirements; not drop-in due to different bias sensitivity and gain profile
BC550C	f_T = 300 MHz; h_FE = 420–800; V_CEO = 45 V; no specified GPE or NF	General-purpose audio/low-speed switching; lacks RF-optimized parameters like Cob, y-parameters, or GPE	Use only for non-RF or low-frequency amplification where gain bandwidth and noise are not critical

Compared with 2SC3356 and BC550C, the KSC2786RTA offers balanced f_T, proven GPE, and documented NF specifically for 100 MHz–200 MHz TV/FM applications - making it more suitable than ultra-high-f_T or general-purpose alternatives when matching legacy RF circuit requirements.

Availability

KSC2786RTA is available at Aetrix Electronics and suitable for TV PIF amplifiers, FM tuner RF amplifiers, mixer stages, and oscillator cores requiring stable component supply in consumer electronics manufacturing.

Supply support for KSC2786RTA 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 and manufacturer of analog and discrete semiconductors, acquired by ON Semiconductor in 2016; known for high-reliability, cost-optimized components for consumer and industrial markets.

The KSC2786RTA belongs to Fairchild's legacy RF transistor product line, engineered specifically for high-gain, low-noise amplification in analog broadcast receiver front-ends including TV and FM radio systems.

FAQ

What is the maximum collector-emitter voltage rating for the KSC2786RTA?

The KSC2786RTA has a maximum collector-emitter voltage (V_CEO) rating of 20 V at T_a = 25°C. This rating applies under open-base conditions with I_C = 5 mA. Exceeding this voltage risks avalanche breakdown and permanent device damage, especially in RF amplifier or oscillator configurations where transient spikes may occur.

Does the KSC2786RTA have a specified noise figure, and at what conditions is it measured?

Yes, the KSC2786RTA has a noise figure (NF) of 3.0–5.0 dB, measured at V_CE = 6 V, I_C = 1 mA, f = 100 MHz, and R_S = 50 Ω. This specification is critical for evaluating its suitability in low-noise RF amplifier stages, and the KSC2786RTA's 5.0 dB max value aligns with FM tuner and TV PIF requirements where moderate SNR preservation is needed.

What is the pin configuration of the KSC2786RTA in its TO-92S package?

The KSC2786RTA uses a standard TO-92S package with 1–2–3 pin order: Pin 1 is Emitter, Pin 2 is Collector, and Pin 3 is Base - viewed with flat side facing outward and leads pointing down. This configuration matches industry-standard NPN transistor orientation and ensures correct PCB layout alignment for RF impedance control and thermal management.

Can the KSC2786RTA be used in oscillator circuits, and what design considerations apply?

Yes, the KSC2786RTA is explicitly recommended for oscillator applications including Colpitts and Hartley topologies. Key design considerations include biasing at V_CE = 6 V and I_C = 1 mA to maximize f_T and minimize phase noise, using Y-class h_FE (120–240) for reliable start-up, and ensuring low-inductance emitter grounding to sustain stable oscillation at VHF frequencies.

What is the power dissipation limit of the KSC2786RTA, and how does it affect thermal design?

The KSC2786RTA has a maximum collector power dissipation (P_C) of 250 mW at T_a = 25°C. Derating is required above 25°C ambient - approximately 2.0 mW/°C - meaning usable power drops to ~150 mW at 75°C. This limit constrains continuous RF output power and necessitates adequate copper pour or heatsinking in TO-92S-mounted PCBs for sustained operation.

KSC2786RTA Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Short Body

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Transistor Type:: NPN

Voltage - Collector Emitter Breakdown (Max):: 20V

Frequency - Transition:: 600MHz

Noise Figure (dB Typ @ f):: 3dB ~ 5dB @ 100MHz

Gain:: 18dB ~ 22dB

Power - Max:: 250mW

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 1mA, 6V

Current - Collector (Ic) (Max):: 20mA

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92S

KSC2786RTA FAQ

1.How can I place an order for KSC2786RTA through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC2786RTA 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 KSC2786RTA reliable?

The price and inventory of KSC2786RTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC2786RTA is usually 5 days.

3.What payment methods are accepted for KSC2786RTA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC2786RTA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC2786RTA?

KSC2786RTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC2786RTA 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 KSC2786RTA?

For technical support, including KSC2786RTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC2786RTA requirements.

6.How does Aetrix verify that KSC2786RTA is sourced from the original manufacturer or authorized distributors?

All KSC2786RTA 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 KSC2786RTA meets industry standards.

7.What is the process for return or replacement of KSC2786RTA?

All KSC2786RTA units undergo pre-shipment inspection (PSI). If there is an issue with KSC2786RTA, 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 KSC2786RTA part is unused and in its original packaging.

Return procedure for KSC2786RTA:

1.Submit a request within 90 days.

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

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