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

onsemi KSC1674OTA

Name: KSC1674OTA
Brand: onsemi
SKU: KSC1674OTA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSC1674OTA

Manufacturer:: onsemi

Category:: Bipolar RF Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: KSC1674OTA.pdf

Description:: RF TRANS NPN 20V 600MHZ TO92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSC1674OTA from ON Semiconductor is an NPN epitaxial silicon transistor optimized for RF amplification and mixing in TV PIF and FM tuner applications, with f_T = 600 MHz (typ.), V_CEO = 20 V, I_C = 20 mA, and V_CE(sat) ≤ 0.3 V at I_C/I_B = 10.

For engineers reviewing the KSC1674OTA datasheet, pinout, applications, or equivalent options, key selection criteria include its high f_T, low noise figure (3.0–5.0 dB at 100 MHz), TO-92 package compatibility, and h_FE classification range (40–240) - critical for RF gain staging and oscillator biasing.

Technical Context

The KSC1674OTA operates as a high-frequency NPN switching and amplifying transistor with epitaxial base construction enabling stable gain up to 600 MHz. Its low C_ob (1.2 pF) and short collector-base time constant (12–15 ps) support wideband RF signal integrity in tuned amplifier and mixer stages.

Designed for low-voltage, low-power RF front-end functions, it delivers V_BE(on) = 0.72 V and V_CE(sat) ≤ 0.3 V under 10 mA/1 mA drive, ensuring efficient biasing in battery-powered tuners and compact TV IF modules without thermal runaway risk.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	20 V - supports operation in standard 12 V TV/FM tuner supply rails with margin against transient spikes
f_T	600 MHz (typ.) - enables stable small-signal amplification through VHF band (up to 230 MHz) with usable gain
h_FE	40–240 - three factory classifications (R/O/Y) allow binning for precise DC bias stability in production RF stages
V_CE(sat)	≤0.3 V at I_C=10 mA, I_B=1 mA - minimizes power loss and self-heating in continuous oscillator and mixer bias networks
NF	3.0–5.0 dB at 100 MHz - meets sensitivity requirements for analog TV PIF and FM front-end low-noise amplification
C_ob	1.2 pF - reduces Miller effect and maintains input impedance match in 75 Ω RF designs
P_C	250 mW - sufficient for Class-A RF amplifiers drawing ≤20 mA with TO-92 thermal dissipation capability

Pinout & Package

Supplied in TO-92 plastic package (3.60 × 4.58 × 14.47 mm), lead-form option "OTA" denotes standard straight-lead configuration with Emitter-Base-Collector pin order (Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector).

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Low-impedance current sink node; connected to ground or emitter degeneration resistor in common-emitter RF amps
Pin 2	Base	High-impedance control terminal; requires DC bias network and RF coupling/decoupling per matching topology
Pin 3	Collector	Active output node; interfaces with tuned LC tank or 75 Ω transmission line via capacitor coupling or transformer

Key Features

Feature	Design Value
High f_T	600 MHz typical - ensures usable gain margin above FM broadcast band (88–108 MHz) and TV PIF (41–47 MHz)
Low noise figure	3.0–5.0 dB at 100 MHz - preserves SNR in weak-signal RF front ends without requiring additional LNA stages
Controlled h_FE bins	R/O/Y classifications (40–80 / 70–140 / 120–240) - enables consistent bias point selection across production batches
Low V_CE(sat)	≤0.3 V - reduces voltage headroom demand and improves efficiency in single-supply 12 V tuner designs
TO-92 mechanical standardization	Compatible with legacy wave-solder and manual assembly tooling used in consumer electronics manufacturing

Applications

TV PIF Amplifier	FM Tuner RF Amplifier
Use Scenario: Amplifies intermediate frequency signal at 41.25 MHz in analog television receivers after channel selection and before video detection. IC Role / Device Role / Timing Role: NPN RF amplifier operating in common-emitter configuration with tuned collector load. Use Value: Delivers >15 dB gain with <5 dB noise figure, maintaining signal fidelity across NTSC/PAL channel bandwidths.	Use Scenario: Boosts weak FM radio signals (88–108 MHz) prior to mixer stage in portable and automotive FM tuners. IC Role / Device Role / Timing Role: Low-noise RF preamplifier with grounded-emitter topology and 50 Ω input matching. Use Value: Enables reception of signals down to –105 dBm while meeting FCC spurious emission limits due to controlled f_T and C_ob.
Mixer Stage	Local Oscillator Driver
Use Scenario: Active mixer core in double-balanced or Gilbert-cell-derived architectures for TV and FM signal conversion. IC Role / Device Role / Timing Role: Switching transistor biased near cutoff to modulate RF/LO paths with minimal distortion. Use Value: Fast turn-on/off (ps-level C_c·rbb′) and low V_CE(sat) ensure clean carrier suppression and intermodulation performance.	Use Scenario: Drives varactor-tuned LC tank in 100–200 MHz local oscillator circuits for TV channel synthesis. IC Role / Device Role / Timing Role: Class-C amplifier sustaining oscillation with high loop gain and low phase noise contribution. Use Value: High h_FE and f_T enable reliable start-up and stable frequency output under temperature variation.

TV PIF Amplifier

FM Tuner RF Amplifier

Use Scenario: Amplifies intermediate frequency signal at 41.25 MHz in analog television receivers after channel selection and before video detection.

IC Role / Device Role / Timing Role: NPN RF amplifier operating in common-emitter configuration with tuned collector load.

Use Value: Delivers >15 dB gain with <5 dB noise figure, maintaining signal fidelity across NTSC/PAL channel bandwidths.

Use Scenario: Boosts weak FM radio signals (88–108 MHz) prior to mixer stage in portable and automotive FM tuners.

IC Role / Device Role / Timing Role: Low-noise RF preamplifier with grounded-emitter topology and 50 Ω input matching.

Use Value: Enables reception of signals down to –105 dBm while meeting FCC spurious emission limits due to controlled f_T and C_ob.

Mixer Stage

Local Oscillator Driver

Use Scenario: Active mixer core in double-balanced or Gilbert-cell-derived architectures for TV and FM signal conversion.

IC Role / Device Role / Timing Role: Switching transistor biased near cutoff to modulate RF/LO paths with minimal distortion.

Use Value: Fast turn-on/off (ps-level C_c·rbb′) and low V_CE(sat) ensure clean carrier suppression and intermodulation performance.

Use Scenario: Drives varactor-tuned LC tank in 100–200 MHz local oscillator circuits for TV channel synthesis.

IC Role / Device Role / Timing Role: Class-C amplifier sustaining oscillation with high loop gain and low phase noise contribution.

Use Value: High h_FE and f_T enable reliable start-up and stable frequency output under temperature variation.

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(TE85L,F)	f_T = 7 GHz (min), higher V_CEO = 20 V, lower noise (1.1 dB typ. at 1 GHz), but tighter bias sensitivity	Preferred for UHF/VHF broadband amplifiers beyond 500 MHz; less suitable for cost-sensitive TV PIF where 600 MHz suffices	Select when designing for >400 MHz operation or requiring sub-2 dB NF; verify base bias stability with higher h_FE spread
BC550C	f_T = 300 MHz (max), V_CEO = 45 V, h_FE = 420–800, but higher C_ob = 4.5 pF and no RF-optimized binning	Suitable for general-purpose audio/low-speed switching; lacks specified noise or high-f_T validation for FM/TV RF stages	Acceptable only in non-critical, narrowband IF amplifiers below 30 MHz; avoid in FM front ends due to degraded gain and matching

Compared with 2SC3356 and BC550C, the KSC1674OTA provides optimal balance of validated 600 MHz f_T, production-grade h_FE binning, and 3–5 dB noise performance specifically for analog TV PIF and FM tuner RF amplification - without over-spec'ing for cost-sensitive consumer applications.

Availability

KSC1674OTA is available at Aetrix Electronics and suitable for TV PIF amplifiers, FM tuner RF amplifiers, mixer stages, and local oscillator drivers requiring stable component supply in high-volume consumer electronics manufacturing.

Supply support for KSC1674OTA 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 is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and logic solutions for automotive, industrial, cloud computing, and consumer markets.

The KSC1674OTA belongs to ON Semiconductor's legacy RF transistor product line, originally developed by Fairchild for analog broadcast receiver front ends - emphasizing high-frequency gain, low noise, and TO-92 manufacturability.

FAQ

What is the pin configuration of the KSC1674OTA?

The KSC1674OTA uses a TO-92 package with Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector - confirmed by Fairchild's original package drawing and ON Semiconductor's updated documentation. This E-B-C order is standard for "OTA" suffix variants and must be verified during PCB layout to prevent reverse-bias damage during operation.

Does the KSC1674OTA have a specified noise figure?

Yes, the KSC1674OTA has a documented noise figure of 3.0–5.0 dB at 100 MHz, V_CE = 6 V, I_C = 1 mA, and R_S = 50 Ω. This value is measured and published in the official datasheet and directly supports its use in low-noise FM tuner RF amplifiers and TV PIF stages.

What h_FE classification does the KSC1674OTA carry?

The KSC1674OTA is manufactured in three h_FE classifications: R (40–80), O (70–140), and Y (120–240). The specific classification is marked on the device body and determines DC bias stability in production RF amplifier designs - critical for yield assurance in TV and tuner manufacturing.

Can the KSC1674OTA replace the KSC1845 in FM tuner circuits?

No - the KSC1845 has V_CEO = 50 V and f_T = 1.1 GHz, making it unsuitable as a direct replacement. The KSC1674OTA's 20 V V_CEO and 600 MHz f_T are intentionally matched to lower-voltage, cost-optimized TV PIF and FM front-end roles; substituting it for KSC1845 risks gain collapse and instability above 200 MHz.

Is the KSC1674OTA RoHS compliant?

Yes, the KSC1674OTA is RoHS compliant per ON Semiconductor's product change notification PCN-1201 and conforms to EU Directive 2011/65/EU. Lead-free TO-92 packaging and halogen-free molding compound meet industrial environmental compliance requirements for global consumer electronics deployment.

KSC1674OTA 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

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

Frequency - Transition:: 600MHz

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

Gain:: -

Power - Max:: 250mW

DC Current Gain (hFE) (Min) @ Ic, Vce:: 70 @ 1mA, 6V

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

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

KSC1674OTA FAQ

1.How can I place an order for KSC1674OTA through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC1674OTA 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 KSC1674OTA reliable?

The price and inventory of KSC1674OTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC1674OTA is usually 5 days.

3.What payment methods are accepted for KSC1674OTA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC1674OTA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC1674OTA?

KSC1674OTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC1674OTA 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 KSC1674OTA?

For technical support, including KSC1674OTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC1674OTA requirements.

6.How does Aetrix verify that KSC1674OTA is sourced from the original manufacturer or authorized distributors?

All KSC1674OTA 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 KSC1674OTA meets industry standards.

7.What is the process for return or replacement of KSC1674OTA?

All KSC1674OTA units undergo pre-shipment inspection (PSI). If there is an issue with KSC1674OTA, 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 KSC1674OTA part is unused and in its original packaging.

Return procedure for KSC1674OTA:

1.Submit a request within 90 days.

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

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