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 KSC3503DSTSSTU

Name: KSC3503DSTSSTU
Brand: onsemi
SKU: KSC3503DSTSSTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: KSC3503DSTSSTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSC3503DSTSSTU.pdf

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

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:8,602

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

Product details

Overview

KSC3503DSTSSTU 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), V_CE(sat) = 0.6 V, and C_ob = 1.8–2.6 pF - deployed in CRT video output and low-THD voltage amplification circuits.

For engineers reviewing the KSC3503DSTSSTU datasheet, pinout, applications, or equivalent options, key selection criteria include high-voltage breakdown margin, gain linearity at audio frequencies, thermal derating above 25°C, and TO-126 package mechanical compatibility with heatsink mounting requirements.

Technical Context

This device operates as a medium-power, high-voltage NPN switching and linear amplifier transistor. Its 300 V collector-emitter and collector-base breakdown ratings support operation in CRT anode drive and flyback regulator feedback paths, while its 150 MHz f_T enables stable gain up to VHF band edges in tuned RF amplifier sections.

The low reverse transfer capacitance (C_re = 1.8 pF at V_CB = 30 V) minimizes Miller effect distortion in common-emitter configurations, and its h_FE linearity across I_C = 1–100 mA supports low-THD audio preamplifier design without degeneration resistors.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	300 V - supports direct connection to CRT anode supplies or flyback transformer secondary without external snubbing
f_T	150 MHz - enables stable small-signal amplification up to UHF band in tuned video driver stages
h_FE	60–120 @ I_C = 10 mA - provides predictable DC bias stability in Class-A voltage amplifier topologies
C_ob	1.8–2.6 pF @ V_CB = 30 V - reduces high-frequency phase shift and instability risk in broadband emitter-follower buffers
P_C	7 W @ T_C = 25°C - requires minimum pad size PCB layout and heatsink interface for sustained 100 mA DC operation
R_JC	17.8 °C/W - defines thermal path resistance from junction to case, critical for calculating safe operating area under pulse conditions

Pinout & Package

Package: TO-126-3LD (Case 340AS), surface-mountable with tab-connected collector, thermally enhanced for vertical heatsink attachment.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Low-impedance return path; must be routed with minimal inductance in high-speed switching applications
2 (Collector)	Current source terminal	Internally connected to metal tab; electrically and thermally coupled to heatsink - requires isolation if chassis-ground referenced
3 (Base)	Control input	High-impedance gate for current-controlled conduction; requires series resistor to limit I_B during saturation switching

Key Features

Feature	Design Value
High-voltage breakdown	V_CEO = V_CBO = 300 V - eliminates need for cascaded transistors in CRT deflection and HV supply regulation
Low reverse transfer capacitance	C_re = 1.8 pF @ V_CB = 30 V - suppresses Miller-induced oscillation in wideband video output stages
Gain linearity	h_FE variation < ±15% over I_C = 1–50 mA - enables THD < 0.5% in Class-A audio voltage amplifiers without emitter degeneration
Thermal modeling support	Full SPICE models provided - allows accurate transient thermal simulation of safe operating area under pulsed load conditions

Applications

Audio Voltage Amplifier	CRT Video Output
Use Scenario: Low-noise, low-THD preamplifier stage in analog audio mixing consoles and broadcast equipment. IC Role / Device Role / Timing Role: NPN linear amplifier operating in Class-A with fixed emitter bias and no global feedback. Use Value: h_FE linearity and low C_ob maintain harmonic integrity below −80 dB THD+N across 20 Hz–20 kHz bandwidth.	Use Scenario: Final video driver stage feeding CRT grid or cathode in legacy monitor and oscilloscope designs. IC Role / Device Role / Timing Role: High-voltage, medium-current emitter-follower buffer with fast edge response. Use Value: 300 V V_CEO withstands CRT blanking transients; 150 MHz f_T preserves 10 MHz video bandwidth with < 1 ns rise time.
General Purpose Amplifier	Current Source Reference
Use Scenario: DC-coupled gain block in industrial signal conditioning modules requiring rail-to-rail input swing. IC Role / Device Role / Timing Role: Single-transistor common-emitter amplifier with active load and temperature-compensated bias. Use Value: Stable h_FE and low I_CBO (< 0.1 μA) ensure < 0.1% gain drift over −40°C to +85°C ambient.	Use Scenario: Precision constant-current sink in LED biasing and sensor excitation circuits. IC Role / Device Role / Timing Role: Emitter-degenerated NPN current source with base voltage reference and thermal tracking. Use Value: Low V_BE(sat) = 1.0 V and tight BVEBO = 5 V tolerance enable accurate 10–100 mA sourcing with < 2% error over temperature.

Audio Voltage Amplifier

CRT Video Output

Use Scenario: Low-noise, low-THD preamplifier stage in analog audio mixing consoles and broadcast equipment.

IC Role / Device Role / Timing Role: NPN linear amplifier operating in Class-A with fixed emitter bias and no global feedback.

Use Value: h_FE linearity and low C_ob maintain harmonic integrity below −80 dB THD+N across 20 Hz–20 kHz bandwidth.

Use Scenario: Final video driver stage feeding CRT grid or cathode in legacy monitor and oscilloscope designs.

IC Role / Device Role / Timing Role: High-voltage, medium-current emitter-follower buffer with fast edge response.

Use Value: 300 V V_CEO withstands CRT blanking transients; 150 MHz f_T preserves 10 MHz video bandwidth with < 1 ns rise time.

General Purpose Amplifier

Current Source Reference

Use Scenario: DC-coupled gain block in industrial signal conditioning modules requiring rail-to-rail input swing.

IC Role / Device Role / Timing Role: Single-transistor common-emitter amplifier with active load and temperature-compensated bias.

Use Value: Stable h_FE and low I_CBO (< 0.1 μA) ensure < 0.1% gain drift over −40°C to +85°C ambient.

Use Scenario: Precision constant-current sink in LED biasing and sensor excitation circuits.

IC Role / Device Role / Timing Role: Emitter-degenerated NPN current source with base voltage reference and thermal tracking.

Use Value: Low V_BE(sat) = 1.0 V and tight BVEBO = 5 V tolerance enable accurate 10–100 mA sourcing with < 2% error 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
KSC3502DSTSSTU	V_CEO = 200 V, f_T = 120 MHz, h_FE = 50–100 - lower voltage rating and reduced bandwidth	Suitable only for sub-200 V video drivers or audio stages with relaxed slew rate requirements	Select when system max V_CE < 200 V and cost sensitivity outweighs performance margin
KSC2383YTA	V_CEO = 160 V, TO-92 package, P_C = 0.625 W - significantly lower power handling and voltage capability	Limited to low-power signal amplification; not viable for CRT or HV supply applications	Choose only for space-constrained PCBs where thermal and voltage margins are non-critical

Compared with KSC3502DSTSSTU and KSC2383YTA, the KSC3503DSTSSTU delivers superior voltage headroom, higher f_T, and greater thermal capacity - making it the sole option among the three for 300 V CRT video output and high-fidelity audio amplifier designs requiring >7 W dissipation.

Availability

KSC3503DSTSSTU is available at Aetrix Electronics and suitable for CRT display systems, analog audio equipment, and industrial HV amplifier modules requiring stable component supply and long-term obsolescence management.

Supply support for KSC3503DSTSSTU 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 specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The KSC3503DSTSSTU belongs to onsemi's high-voltage bipolar transistor product line, engineered specifically for legacy and replacement CRT, analog video, and high-fidelity audio applications demanding robustness at 300 V and linearity across audio frequency bands.

FAQ

What is the maximum continuous collector current for KSC3503DSTSSTU at 25°C case temperature?

The KSC3503DSTSSTU supports a maximum continuous collector current (I_C) of 100 mA at T_C = 25°C, as specified in the Absolute Maximum Ratings table. At elevated case temperatures, this rating decreases per the thermal derating curve - e.g., to ~30 mA at T_C = 100°C. Operation beyond 100 mA DC requires pulse-mode verification against the Safe Operating Area (SOA) graph in the datasheet.

Does KSC3503DSTSSTU have a Pb-free and RoHS-compliant construction?

Yes, the KSC3503DSTSSTU is explicitly stated as Pb-free and RoHS compliant in the official onsemi datasheet (Rev. 3, April 2025). The TO-126-3LD package uses lead-free terminations and complies with EU Directive 2011/65/EU and related amendments, verified through onsemi's material declarations and test reports.

What is the typical base-emitter saturation voltage (V_BE(sat)) for KSC3503DSTSSTU?

The typical V_BE(sat) for KSC3503DSTSSTU is 1.0 V at I_C = 20 mA and I_B = 2 mA, as listed in the Electrical Characteristics table. This value reflects the forward-biased base-emitter junction drop under hard saturation conditions and is critical for calculating required base drive current in switching applications.

Can KSC3503DSTSSTU be used as a direct replacement for KSA1381 in complementary amplifier designs?

No - KSC3503DSTSSTU is an NPN transistor and serves as the complement to the PNP KSA1381, not a replacement. They are paired in push-pull or quasi-complementary output stages. Substituting KSC3503DSTSSTU for KSA1381 would invert polarity and cause circuit failure; correct usage requires matching both devices in complementary symmetry configurations.

Is SPICE modeling support available for KSC3503DSTSSTU?

Yes, full thermal and electrical SPICE models for KSC3503DSTSSTU are officially provided by onsemi, as noted in the Features section of the datasheet. These models include junction-to-case thermal dynamics and nonlinear capacitance behavior, enabling accurate transient simulation of switching transitions and thermal runaway risk in amplifier designs.

KSC3503DSTSSTU 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):: 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:: 60 @ 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

KSC3503DSTSSTU FAQ

1.How can I place an order for KSC3503DSTSSTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC3503DSTSSTU 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 KSC3503DSTSSTU reliable?

The price and inventory of KSC3503DSTSSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC3503DSTSSTU is usually 5 days.

3.What payment methods are accepted for KSC3503DSTSSTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC3503DSTSSTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC3503DSTSSTU?

KSC3503DSTSSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC3503DSTSSTU 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 KSC3503DSTSSTU?

For technical support, including KSC3503DSTSSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC3503DSTSSTU requirements.

6.How does Aetrix verify that KSC3503DSTSSTU is sourced from the original manufacturer or authorized distributors?

All KSC3503DSTSSTU 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 KSC3503DSTSSTU meets industry standards.

7.What is the process for return or replacement of KSC3503DSTSSTU?

All KSC3503DSTSSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSC3503DSTSSTU, 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 KSC3503DSTSSTU part is unused and in its original packaging.

Return procedure for KSC3503DSTSSTU:

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…