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

onsemi KSC1187OTA

Name: KSC1187OTA
Brand: onsemi
SKU: KSC1187OTA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSC1187OTA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSC1187OTA.pdf

Description:: TRANS NPN 20V 0.03A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSC1187OTA from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for TV first- and second-stage picture IF amplification with forward AGC functionality, featuring f_T = 700 MHz (max), G_PE = 24 dB (typ.) at 45 MHz, and V_CEO = 25 V (min).

For engineers reviewing the KSC1187OTA datasheet, pinout, applications, or equivalent options, key selection criteria include high-frequency gain-bandwidth performance, AGC voltage range (4.4–6.0 V), TO-92 package compatibility, and h_FE classification (R/O/Y) for bias stability in analog IF stages.

Technical Context

The KSC1187OTA operates as a high-f_T RF amplifier transistor optimized for 45 MHz IF signal paths in analog television receivers. Its forward AGC interface requires precise V_AGC control (4.4–6.0 V) to modulate gain without distortion, while low C_re (0.6 pF) minimizes feedback instability.

DC biasing relies on h_FE classification (R: 40–80, O: 70–140, Y: 120–240) to maintain consistent gain across production lots. The device sustains operation up to T_J = 150°C and supports V_CBO = 30 V, enabling robust headroom in multi-stage IF chains.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	25 V min - ensures safe operation under transient IF stage collector swing
f_T	700 MHz max - enables stable small-signal amplification at 45 MHz with margin
G_PE	24 dB typ. @ 45 MHz - delivers high power gain in TV IF amplifier stages
V_AGC	4.4–6.0 V - defines usable AGC control voltage window for gain linearization
C_re	0.6 pF @ 10 V - limits Miller-effect feedback to preserve bandwidth and stability
h_FE (Y-class)	120–240 @ V_CE=10 V, I_C=2 mA - supports predictable DC bias design in AGC-coupled stages
P_C	250 mW - sets thermal derating limit for continuous 45 MHz operation in TO-92

Pinout & Package

Package: TO-92 - standard through-hole plastic package with 1.27 mm lead pitch, 3.60 mm body width, and 4.58 mm height; suitable for wave soldering and manual assembly in consumer TV IF modules.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to AGC-controlled bias network; low-impedance path for emitter degeneration
2 (Base)	Signal input & bias control node	Receives tuned IF signal and AGC-derived base bias; high-impedance node requiring shielding
3 (Collector)	Active output terminal	Drives next IF stage via tuned collector load; handles 25 V peak swing with minimal saturation

Key Features

Feature	Design Value
High f_T bandwidth	700 MHz max enables stable 45 MHz IF amplification with >15× frequency margin
Forward AGC interface	V_AGC = 4.4–6.0 V range allows direct coupling to TV AGC detector outputs
Low reverse transfer capacitance	C_re = 0.6 pF minimizes unwanted feedback in high-gain IF stages
Classified h_FE bins	R/O/Y groupings ensure predictable DC operating point selection across production lots
TO-92 mechanical standardization	Compatible with legacy TV IF board layouts and automated insertion equipment

Applications

TV Analog IF Amplifier	Video Signal Processor Front-End
Use Scenario: First- and second-stage intermediate frequency amplification in CRT-based analog television receivers. IC Role / Device Role / Timing Role: NPN RF transistor providing voltage-controlled gain via forward AGC voltage applied to base bias network. Use Value: Delivers 24 dB power gain at 45 MHz with 700 MHz f_T margin, ensuring stable amplification across temperature and supply variations.	Use Scenario: Low-noise pre-amplification of composite video IF signals before demodulation and sync separation. IC Role / Device Role / Timing Role: High-linearity NPN transistor configured in common-emitter topology with emitter degeneration for gain stability. Use Value: Low C_re (0.6 pF) and controlled h_FE binning reduce inter-stage coupling and improve SNR in multi-stage video IF chains.
Consumer Audio IF Stage	Legacy Broadcast Receiver Tuner
Use Scenario: Intermediate frequency amplification in AM/FM stereo multiplex receivers requiring AGC-responsive gain control. IC Role / Device Role / Timing Role: Forward AGC transistor where V_AGC adjusts base current to compress gain during strong signal conditions. Use Value: 4.4–6.0 V V_AGC range matches standard broadcast AGC detector outputs, eliminating external level-shifting circuitry.	Use Scenario: Tuner IF strip in UHF/VHF broadcast receivers prior to ceramic filter and demodulator stages. IC Role / Device Role / Timing Role: High-f_T NPN transistor used in cascode or single-ended IF amplifier configurations. Use Value: 250 mW power dissipation and 150°C junction rating support continuous operation in enclosed tuner modules with limited airflow.

TV Analog IF Amplifier

Video Signal Processor Front-End

Use Scenario: First- and second-stage intermediate frequency amplification in CRT-based analog television receivers.

IC Role / Device Role / Timing Role: NPN RF transistor providing voltage-controlled gain via forward AGC voltage applied to base bias network.

Use Value: Delivers 24 dB power gain at 45 MHz with 700 MHz f_T margin, ensuring stable amplification across temperature and supply variations.

Use Scenario: Low-noise pre-amplification of composite video IF signals before demodulation and sync separation.

IC Role / Device Role / Timing Role: High-linearity NPN transistor configured in common-emitter topology with emitter degeneration for gain stability.

Use Value: Low C_re (0.6 pF) and controlled h_FE binning reduce inter-stage coupling and improve SNR in multi-stage video IF chains.

Consumer Audio IF Stage

Legacy Broadcast Receiver Tuner

Use Scenario: Intermediate frequency amplification in AM/FM stereo multiplex receivers requiring AGC-responsive gain control.

IC Role / Device Role / Timing Role: Forward AGC transistor where V_AGC adjusts base current to compress gain during strong signal conditions.

Use Value: 4.4–6.0 V V_AGC range matches standard broadcast AGC detector outputs, eliminating external level-shifting circuitry.

Use Scenario: Tuner IF strip in UHF/VHF broadcast receivers prior to ceramic filter and demodulator stages.

IC Role / Device Role / Timing Role: High-f_T NPN transistor used in cascode or single-ended IF amplifier configurations.

Use Value: 250 mW power dissipation and 150°C junction rating support continuous operation in enclosed tuner modules with limited airflow.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN RF amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SC2878	f_T = 600 MHz (max), V_CEO = 20 V, no specified V_AGC parameter	Lacks documented forward AGC interface; requires external bias compensation	Select when AGC control is implemented externally and lower f_T margin is acceptable
BC557B	PNP polarity, f_T = 100 MHz, V_CEO = 45 V, not rated for 45 MHz IF use	Not suitable for high-frequency IF amplification; intended for general-purpose low-speed switching	Reject for KSC1187OTA replacement; incompatible polarity and bandwidth

Compared with 2SC2878 and BC557B, the KSC1187OTA uniquely integrates forward AGC voltage specification (4.4–6.0 V), 700 MHz f_T, and Y-class h_FE binning-enabling drop-in use in legacy TV IF designs without bias recalibration or layout changes.

Availability

KSC1187OTA is available at Aetrix Electronics and suitable for analog TV IF amplifiers, broadcast receiver tuners, video signal processors, and legacy consumer electronics requiring stable component supply with full traceability.

Supply support for KSC1187OTA 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 U.S.-based semiconductor manufacturer specializing in discrete power devices, analog ICs, and optoelectronics before its acquisition by ON Semiconductor in 2016.

The KSC1187OTA belongs to Fairchild's legacy RF transistor product line, engineered specifically for high-frequency analog IF amplification in analog television and broadcast equipment with emphasis on AGC responsiveness and thermal reliability.

FAQ

What is the maximum operating frequency supported by the KSC1187OTA?

The KSC1187OTA has a current gain–bandwidth product (f_T) of up to 700 MHz, meaning it maintains usable gain well into UHF bands. In practice, it is optimized for stable 45 MHz IF amplification in analog TV systems, with sufficient bandwidth margin to avoid phase shift and instability in multi-stage configurations. The KSC1187OTA achieves this while maintaining low C_re (0.6 pF) to suppress feedback.

Does the KSC1187OTA support forward AGC, and what is its specified voltage range?

Yes, the KSC1187OTA is explicitly characterized for forward AGC operation with a defined V_AGC range of 4.4–6.0 V at GR = 30 dB and f = 45 MHz. This allows direct interfacing with standard TV AGC detector circuits without level-shifting components. The KSC1187OTA's base bias network is designed to respond linearly within this window, enabling precise gain control in IF amplifier stages.

What h_FE classification does the KSC1187OTA carry, and why does it matter?

The KSC1187OTA is offered in R (40–80), O (70–140), and Y (120–240) h_FE classifications. This binning ensures predictable DC operating points across production lots-critical for stable gain and bias in AGC-coupled IF amplifiers. Selecting the correct KSC1187OTA variant avoids manual bias resistor adjustments during manufacturing and improves yield in high-volume TV IF module assembly.

Is the KSC1187OTA compatible with TO-92 footprint and assembly processes?

Yes, the KSC1187OTA uses the standard TO-92 package with verified dimensions: 3.60 ± 0.20 mm body width, 4.58 +0.25/–0.15 mm height, and 1.27 mm lead pitch. It supports wave soldering, hand soldering, and automated insertion per JEDEC TO-92 standards. The KSC1187OTA's pinout (Emitter-Base-Collector = Pin 1-2-3) matches industry-standard TO-92 NPN orientation, ensuring drop-in compatibility with legacy TV IF PCBs.

What is the absolute maximum collector-emitter voltage rating for the KSC1187OTA?

The KSC1187OTA has an absolute maximum V_CEO rating of 25 V (tested at I_C = 5 mA, I_B = 0). This provides safe headroom for typical analog TV IF collector swings, which rarely exceed 15 V peak-to-peak. Exceeding 25 V risks avalanche breakdown; derating to ≤18 V is recommended for long-term reliability in thermally constrained tuner modules using the KSC1187OTA.

KSC1187OTA 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):: 30 mA

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

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 70 @ 2mA, 10V

Power - Max:: 250 mW

Frequency - Transition:: 700MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

KSC1187OTA FAQ

1.How can I place an order for KSC1187OTA through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC1187OTA 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 KSC1187OTA reliable?

The price and inventory of KSC1187OTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC1187OTA is usually 5 days.

3.What payment methods are accepted for KSC1187OTA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC1187OTA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC1187OTA?

KSC1187OTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC1187OTA 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 KSC1187OTA?

For technical support, including KSC1187OTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC1187OTA requirements.

6.How does Aetrix verify that KSC1187OTA is sourced from the original manufacturer or authorized distributors?

All KSC1187OTA 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 KSC1187OTA meets industry standards.

7.What is the process for return or replacement of KSC1187OTA?

All KSC1187OTA units undergo pre-shipment inspection (PSI). If there is an issue with KSC1187OTA, 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 KSC1187OTA part is unused and in its original packaging.

Return procedure for KSC1187OTA:

1.Submit a request within 90 days.

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

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