Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

onsemi KSC2688YSTU

Name: KSC2688YSTU
Brand: onsemi
SKU: KSC2688YSTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: KSC2688YSTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: KSC2688YSTU.pdf

Description:: TRANS NPN 300V 0.2A TO-126-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:5,836

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

KSC2688YSTU from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for high-voltage video output stages in color TV systems, featuring V_CEO = 300 V, I_C = 200 mA, P_C = 10 W (T_C = 25°C), and f_T = 50–80 MHz. It operates in linear amplification mode with h_FE ranging 40–250 depending on grade.

For engineers reviewing the KSC2688YSTU datasheet, pinout, applications, or equivalent options, key selection criteria include high-voltage breakdown capability, thermal performance in TO-126 package, DC current gain classification, saturation voltage at drive conditions, and chroma/video signal bandwidth requirements.

Technical Context

The KSC2688YSTU is a single NPN bipolar junction transistor optimized for video output amplification where high collector-emitter breakdown voltage and stable gain at moderate frequencies are required. Its structure supports operation up to 150°C junction temperature with low feedback capacitance (C_re = 3 pF at V_CB = 30 V).

It uses epitaxial base construction to achieve consistent h_FE across grades (R/O/Y/G) and low V_CE(sat) (1.5 V max at I_C = 50 mA, I_B = 5 mA). Power derating curves confirm usable dissipation down to T_C = 100°C before linear reduction begins.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	300 V - Enables direct interface with CRT anode supply rails without external snubbing.
I_C	200 mA - Supports peak video output current for chroma driver stage in analog TV systems.
P_C (T_C=25°C)	10 W - Allows high-power linear operation when mounted on heatsink with case temperature control.
f_T	50–80 MHz - Sufficient bandwidth for composite video (4.2–4.4 MHz) and chroma subcarrier (3.58 MHz) amplification.
h_FE	40–250 - Grade-dependent DC gain enables precise biasing in fixed-gain video output designs.
V_CE(sat)	1.5 V max - Minimizes conduction loss and self-heating during active pull-down in emitter-follower configuration.
C_re	3 pF - Low feedback capacitance preserves stability in high-gain video amplifier feedback loops.

Pinout & Package

Package: TO-126 - Molded plastic power package with metal tab for heatsinking; pin 1 = Emitter, pin 2 = Collector (tab-connected), pin 3 = Base.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-impedance return path; requires low-inductance layout for video fidelity.
2 (Collector)	High-voltage output node	Internally bonded to metal tab; must be electrically isolated from heatsink unless common-ground design.
3 (Base)	Control input	Receives drive current from preceding stage; sensitive to noise due to high h_FE range.

Key Features

Feature	Design Value
High V_CEO rating	300 V withstand enables direct connection to CRT anode supplies up to 25 kV flyback-derived rails.
Grade-coded h_FE	R/O/Y/G bins allow production matching of gain for consistent video output linearity across units.
Low C_re	3 pF minimizes Miller effect, supporting stable wideband operation without neutralization networks.
TO-126 thermal design	10 W dissipation at T_C = 25°C supports compact heatsink integration in space-constrained TV chassis layouts.
Epitaxial base process	Ensures tight parameter distribution and reliable operation under repetitive video pulse stress.

Applications

Color TV Chroma Output	Color TV Video Output
Use Scenario: Amplifying 3.58 MHz chroma signal in NTSC/PAL decoder output stage prior to matrix mixing. IC Role / Device Role / Timing Role: Linear NPN amplifier operating in Class-A or AB with fixed bias network. Use Value: High V_CEO prevents breakdown during sync tip excursions; h_FE grading ensures consistent color saturation across production units.	Use Scenario: Driving composite video signal to RF modulator or monitor output in analog broadcast receivers. IC Role / Device Role / Timing Role: Emitter-follower buffer delivering 1 V_PP into 75 Ω load with minimal overshoot. Use Value: Low V_CE(sat) and 80 MHz f_T preserve rise/fall times; TO-126 tab aids thermal management during sustained white-level output.
Video Monitor Output Stage	Legacy Broadcast Equipment
Use Scenario: Final video amplification in professional analog monitors requiring DC-coupled output and wide dynamic range. IC Role / Device Role / Timing Role: High-voltage linear amplifier with active load compensation. Use Value: 300 V V_CBO accommodates DC restoration clamping voltages; low C_re avoids high-frequency peaking in flat-response design.	Use Scenario: Signal conditioning in aging studio equipment maintaining NTSC signal integrity over long cable runs. IC Role / Device Role / Timing Role: Gain-stable video driver with predictable h_FE drift over time and temperature. Use Value: Epitaxial construction provides long-term parameter stability; TO-126 mechanical robustness supports field-replaceable module design.

Color TV Chroma Output

Color TV Video Output

Use Scenario: Amplifying 3.58 MHz chroma signal in NTSC/PAL decoder output stage prior to matrix mixing.

IC Role / Device Role / Timing Role: Linear NPN amplifier operating in Class-A or AB with fixed bias network.

Use Value: High V_CEO prevents breakdown during sync tip excursions; h_FE grading ensures consistent color saturation across production units.

Use Scenario: Driving composite video signal to RF modulator or monitor output in analog broadcast receivers.

IC Role / Device Role / Timing Role: Emitter-follower buffer delivering 1 V_PP into 75 Ω load with minimal overshoot.

Use Value: Low V_CE(sat) and 80 MHz f_T preserve rise/fall times; TO-126 tab aids thermal management during sustained white-level output.

Video Monitor Output Stage

Legacy Broadcast Equipment

Use Scenario: Final video amplification in professional analog monitors requiring DC-coupled output and wide dynamic range.

IC Role / Device Role / Timing Role: High-voltage linear amplifier with active load compensation.

Use Value: 300 V V_CBO accommodates DC restoration clamping voltages; low C_re avoids high-frequency peaking in flat-response design.

Use Scenario: Signal conditioning in aging studio equipment maintaining NTSC signal integrity over long cable runs.

IC Role / Device Role / Timing Role: Gain-stable video driver with predictable h_FE drift over time and temperature.

Use Value: Epitaxial construction provides long-term parameter stability; TO-126 mechanical robustness supports field-replaceable module design.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN high-voltage video amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SC4027	V_CEO = 250 V, f_T = 60 MHz, TO-126, h_FE = 60–120 (no grade coding)	Limited headroom for 300 V CRT anode coupling; lower max voltage restricts use in higher-voltage legacy designs.	Select when 250 V margin suffices and simplified h_FE binning is acceptable.
KSC2690	V_CEO = 400 V, I_C = 200 mA, P_C = 10 W, same TO-126, h_FE = 40–250 graded	Higher breakdown allows extended use in modified flyback topologies; identical pinout and thermal profile.	Choose for upgraded voltage margin while retaining PCB layout and heatsink compatibility.

Compared with 2SC4027 and KSC2690, the KSC2688YSTU offers optimal balance of 300 V rating, graded h_FE, and proven chroma linearity-making it the reference choice for original-equipment color TV video output where exact legacy specification compliance is required.

Availability

KSC2688YSTU is available at Aetrix Electronics and suitable for color TV repair, analog video equipment refurbishment, and legacy broadcast signal chain maintenance requiring stable component supply and long-lifecycle support.

Supply support for KSC2688YSTU 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 company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The KSC2688YSTU belongs to Fairchild's legacy high-voltage bipolar transistor family, engineered specifically for analog video signal amplification in consumer television and professional monitor applications.

FAQ

What is the maximum collector-emitter voltage rating for KSC2688YSTU?

The KSC2688YSTU has a guaranteed minimum V_CEO of 300 V at I_C = 5 mA and T_C = 25°C. This rating is validated per JEDEC test conditions and supports direct interface with CRT anode supplies in legacy color TV designs. Operation above this voltage risks avalanche breakdown and permanent device failure. The KSC2688YSTU must not be substituted with lower-V_CEO transistors without circuit revalidation.

Does KSC2688YSTU have a specified hFE grade, and how is it marked?

Yes, the KSC2688YSTU is manufactured in four h_FE grades-R (40–80), O (60–120), Y (100–200), and G (160–250)-indicated by color dot coding on the package. The "YSTU" suffix corresponds to the Y-grade variant (h_FE = 100–200), confirmed in Fairchild's Rev. A datasheet. This grading enables consistent bias point selection in production video output stages.

What is the thermal resistance of KSC2688YSTU in TO-126 package?

The KSC2688YSTU does not specify R_θJC or R_θJA numerically in its datasheet, but its power derating curve shows linear reduction from 10 W at T_C = 25°C to 0 W at T_C = 175°C. This implies an effective R_θJC ≈ 15°C/W. For reliable operation, the KSC2688YSTU requires a heatsink that maintains case temperature ≤100°C under full load.

Can KSC2688YSTU be used as a direct replacement for KSC2688Y in existing designs?

Yes, KSC2688YSTU is a standardized ordering variant of the KSC2688Y transistor, with identical electrical specifications, TO-126 package, pinout, and h_FE grade (Y). The "STU" suffix denotes tape-and-reel packaging and standard temperature grade (–55°C to +150°C), making KSC2688YSTU fully compatible with KSC2688Y in both schematic and layout implementation.

What is the typical feedback capacitance (C_re) of KSC2688YSTU, and why does it matter?

The KSC2688YSTU exhibits C_re = 3 pF at V_CB = 30 V and f = 1 MHz. This low value reduces Miller multiplication in high-gain video amplifiers, preventing unwanted peaking or oscillation in broadband feedback configurations. Maintaining low C_re is critical for stable chroma amplification-where the KSC2688YSTU delivers predictable phase response without neutralization networks.

KSC2688YSTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 200 mA

Voltage - Collector Emitter Breakdown (Max):: 300 V

Vce Saturation (Max) @ Ib, Ic:: 1.5V @ 5mA, 50mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 10mA, 10V

Power - Max:: 1.25 W

Frequency - Transition:: 80MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

KSC2688YSTU FAQ

1.How can I place an order for KSC2688YSTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC2688YSTU 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 KSC2688YSTU reliable?

The price and inventory of KSC2688YSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC2688YSTU is usually 5 days.

3.What payment methods are accepted for KSC2688YSTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC2688YSTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC2688YSTU?

KSC2688YSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC2688YSTU 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 KSC2688YSTU?

For technical support, including KSC2688YSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC2688YSTU requirements.

6.How does Aetrix verify that KSC2688YSTU is sourced from the original manufacturer or authorized distributors?

All KSC2688YSTU 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 KSC2688YSTU meets industry standards.

7.What is the process for return or replacement of KSC2688YSTU?

All KSC2688YSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSC2688YSTU, 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 KSC2688YSTU part is unused and in its original packaging.

Return procedure for KSC2688YSTU:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…