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

onsemi KSC3503DSTU

Name: KSC3503DSTU
Brand: onsemi
SKU: KSC3503DSTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSC3503DSTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSC3503DSTU.pdf

Description:: TRANS NPN 300V 0.1A TO-126-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSC3503DSTU from onsemi is an NPN epitaxial silicon transistor designed for high-voltage audio and video amplifier stages, featuring V_CEO = 300 V, f_T = 150 MHz, h_FE = 60–120 (at I_C = 10 mA), C_ob = 1.8–2.6 pF, and TO-126-3LD package. It serves as a voltage/current amplifier in CRT video output and low-THD audio circuits.

For engineers reviewing the KSC3503DSTU datasheet, pinout, applications, or equivalent options, key selection criteria include high-voltage breakdown rating, gain linearity at audio frequencies, thermal resistance (R_θJC = 17.8°C/W), and Pb-free RoHS-compliant packaging for industrial display and amplifier designs.

Technical Context

This NPN transistor operates with full thermal and electrical SPICE models available, supporting accurate simulation of dynamic behavior in high-frequency analog stages. Its gain linearity minimizes total harmonic distortion in Class-A/B audio amplifiers, while the 300 V collector-emitter breakdown enables safe operation in CRT flyback and horizontal deflection circuits.

The device exhibits low reverse transfer capacitance (C_re = 1.8 pF at V_CB = 30 V) and high f_T, making it suitable for wideband small-signal amplification up to 150 MHz. Its TO-126-3LD package provides mechanical stability and thermal path integrity for continuous-duty linear applications.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	300 V - Enables use in high-voltage CRT video output and flyback driver stages without derating.
f_T	150 MHz - Supports stable small-signal amplification up to VHF band in RF/audio hybrid circuits.
h_FE	60–120 @ I_C = 10 mA - Provides predictable DC biasing and gain control in linear amplifier topologies.
C_ob	1.8–2.6 pF @ V_CB = 30 V - Minimizes Miller effect and improves high-frequency stability in common-emitter configurations.
R_θJC	17.8°C/W - Allows 7 W dissipation at T_C = 25°C, supporting thermally constrained PCB layouts.
V_BE(sat)	1.0 V @ I_C = 20 mA, I_B = 2 mA - Defines base drive requirement for saturated switching in current-source applications.

Pinout & Package

Package: TO-126-3LD (Case 340AS), surface-mount compatible with through-hole mounting, Pb-free and RoHS compliant.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-impedance return path; defines reference for V_BE and I_C control.
2 (Collector)	High-voltage output node	Handles up to 300 V DC; requires adequate creepage clearance in CRT and HV amplifier PCBs.
3 (Base)	Control input	Drives transistor into active/saturation via 2 mA typical base current; sensitive to ESD per BVEBO = 5 V limit.

Key Features

Feature	Design Value
High-voltage capability	V_CEO = V_CBO = 300 V supports direct integration into CRT horizontal deflection and HV power supply feedback loops.
Low reverse transfer capacitance	C_re = 1.8 pF reduces unwanted coupling between collector and base, improving stability in high-gain video amplifiers.
Gain linearity	Excellent h_FE consistency across I_C range ensures low THD in Class-A audio preamplifier stages.
SPICE model availability	Full thermal and electrical SPICE models enable accurate transient and AC simulation before prototype build.

Applications

Audio Amplifier Stage	Video Output Driver
Use Scenario: Low-distortion voltage amplification in Class-A/B preamp and driver stages for hi-fi receivers. IC Role / Device Role / Timing Role: NPN small-signal amplifier providing linear gain with minimal harmonic generation. Use Value: h_FE linearity and low C_ob reduce second/third harmonic content below measurable thresholds at 1 kHz–20 kHz.	Use Scenario: CRT monitor video output stage driving 75 Ω coaxial cable to deflection yoke or RGB grid. IC Role / Device Role / Timing Role: High-voltage, medium-current emitter-follower or common-emitter buffer. Use Value: 300 V V_CEO withstands flyback-induced transients; 150 MHz f_T preserves video bandwidth up to 5 MHz.
General-Purpose Linear Amplifier	Current Source for Bias Networks
Use Scenario: DC-coupled gain block in test equipment signal chains requiring stable DC offset control. IC Role / Device Role / Timing Role: Active load or transconductance amplifier in precision analog front-ends. Use Value: Tight h_FE spread (60–120) and low I_CBO (<0.1 μA) ensure repeatable quiescent current setting.	Use Scenario: Constant-current source for LED biasing or op-amp input stage tail current in analog ICs. IC Role / Device Role / Timing Role: Two-terminal current regulator using emitter degeneration and base voltage reference. Use Value: V_BE(sat) = 1.0 V and R_θJC = 17.8°C/W allow stable 20–100 mA sourcing with <±2% drift over temperature.

Audio Amplifier Stage

Video Output Driver

Use Scenario: Low-distortion voltage amplification in Class-A/B preamp and driver stages for hi-fi receivers.

IC Role / Device Role / Timing Role: NPN small-signal amplifier providing linear gain with minimal harmonic generation.

Use Value: h_FE linearity and low C_ob reduce second/third harmonic content below measurable thresholds at 1 kHz–20 kHz.

Use Scenario: CRT monitor video output stage driving 75 Ω coaxial cable to deflection yoke or RGB grid.

IC Role / Device Role / Timing Role: High-voltage, medium-current emitter-follower or common-emitter buffer.

Use Value: 300 V V_CEO withstands flyback-induced transients; 150 MHz f_T preserves video bandwidth up to 5 MHz.

General-Purpose Linear Amplifier

Current Source for Bias Networks

Use Scenario: DC-coupled gain block in test equipment signal chains requiring stable DC offset control.

IC Role / Device Role / Timing Role: Active load or transconductance amplifier in precision analog front-ends.

Use Value: Tight h_FE spread (60–120) and low I_CBO (<0.1 μA) ensure repeatable quiescent current setting.

Use Scenario: Constant-current source for LED biasing or op-amp input stage tail current in analog ICs.

IC Role / Device Role / Timing Role: Two-terminal current regulator using emitter degeneration and base voltage reference.

Use Value: V_BE(sat) = 1.0 V and R_θJC = 17.8°C/W allow stable 20–100 mA sourcing with <±2% drift over temperature.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
KSC3502DSTU	V_CEO = 200 V (lower), f_T = 120 MHz, same TO-126-3LD package and pinout.	Not suitable for >200 V CRT flyback circuits; acceptable for lower-voltage audio and general-purpose use.	Select when system voltage remains ≤200 V and cost sensitivity outweighs 300 V margin.
KSC2383YTA	V_CEO = 160 V, h_FE = 80–240, TO-92 package (smaller, higher R_θJA).	Limited to low-power portable audio; unsuitable for thermal-intensive video output or HV linear operation.	Choose only for space-constrained, low-dissipation applications where 300 V rating is unnecessary.

Compared with KSC3502DSTU and KSC2383YTA, the KSC3503DSTU delivers unique 300 V robustness and 150 MHz bandwidth in a thermally capable TO-126 package-making it irreplaceable in CRT video output and high-fidelity HV amplifier designs where voltage margin and gain stability are non-negotiable.

Availability

KSC3503DSTU is available at Aetrix Electronics and suitable for CRT display systems, high-fidelity audio amplifiers, and general-purpose linear amplifier circuits requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for KSC3503DSTU 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, delivering high-performance analog, logic, discrete, and custom devices.

The KSC3503DSTU belongs to onsemi's high-voltage bipolar transistor product line, engineered specifically for reliability-critical analog signal conditioning in display, audio, and industrial power control systems.

FAQ

What is the maximum collector-emitter voltage rating for KSC3503DSTU?

The KSC3503DSTU has a guaranteed minimum collector-emitter breakdown voltage (BV_CEO) of 300 V at I_C = 1 mA and I_B = 0. This rating is validated per onsemi's absolute maximum ratings table and applies under DC and pulsed conditions within specified thermal limits. The KSC3503DSTU must not be operated beyond this voltage without appropriate derating based on junction temperature.

Is KSC3503DSTU RoHS compliant and lead-free?

Yes, the KSC3503DSTU is explicitly marked Pb-free and RoHS compliant per onsemi's datasheet revision 3 (April 2025). The TO-126-3LD package uses lead-free terminations and complies with EU Directive 2011/65/EU. Full compliance documentation, including material declarations, is available through onsemi's official product page and Aetrix Electronics' traceable sourcing records for the KSC3503DSTU.

What is the thermal resistance from junction to case for KSC3503DSTU?

The KSC3503DSTU has a thermal resistance R_θJC of 17.8°C/W when mounted on minimum pad size, as specified in the Thermal Characteristics section of the onsemi datasheet. This value enables 7 W power dissipation at T_C = 25°C and informs heatsink sizing for continuous-duty linear amplifier applications using the KSC3503DSTU.

Does KSC3503DSTU have SPICE models available for circuit simulation?

Yes, full thermal and electrical SPICE models for the KSC3503DSTU are officially provided by onsemi and accessible via their website's design resources library. These models include temperature-dependent parameters and accurately replicate DC, AC, and transient behavior-enabling reliable pre-layout validation of amplifier stability, gain, and distortion performance using the KSC3503DSTU.

What is the pin configuration of KSC3503DSTU in the TO-126-3LD package?

The KSC3503DSTU uses a standard TO-126-3LD pinout: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base - verified from the marking diagram and mechanical outline in the onsemi datasheet. This configuration is consistent across all KSC3503 variants and matches industry-standard NPN orientation for TO-126 packages, ensuring compatibility with existing layout footprints for the KSC3503DSTU.

KSC3503DSTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tube

Product Status:: Last Time Buy

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 100 mA

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

Vce Saturation (Max) @ Ib, Ic:: 600mV @ 2mA, 20mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 10mA, 10V

Power - Max:: 7 W

Frequency - Transition:: 150MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

KSC3503DSTU FAQ

1.How can I place an order for KSC3503DSTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC3503DSTU 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 KSC3503DSTU reliable?

The price and inventory of KSC3503DSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC3503DSTU is usually 5 days.

3.What payment methods are accepted for KSC3503DSTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC3503DSTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC3503DSTU?

KSC3503DSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC3503DSTU 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 KSC3503DSTU?

For technical support, including KSC3503DSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC3503DSTU requirements.

6.How does Aetrix verify that KSC3503DSTU is sourced from the original manufacturer or authorized distributors?

All KSC3503DSTU 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 KSC3503DSTU meets industry standards.

7.What is the process for return or replacement of KSC3503DSTU?

All KSC3503DSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSC3503DSTU, 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 KSC3503DSTU part is unused and in its original packaging.

Return procedure for KSC3503DSTU:

1.Submit a request within 90 days.

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

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