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 KSC2859YMTF

Name: KSC2859YMTF
Brand: onsemi
SKU: KSC2859YMTF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: KSC2859YMTF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: KSC2859YMTF.pdf

Description:: TRANS NPN 30V 0.5A SOT-23-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:6,553

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

Product details

Overview

KSC2859YMTF from ON Semiconductor is an NPN bipolar junction transistor (BJT) optimized for general-purpose switching and amplification in low-voltage, medium-current applications; features V_CEO = 40 V, I_C = 200 mA, h_FE = 120–240 at I_C = 2 mA, f_T = 180 MHz, and operates with a maximum power dissipation of 200 mW in the SOT-23 package.

For engineers reviewing the KSC2859YMTF datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain consistency across bias conditions, transition frequency suitability for audio and low-speed digital signal buffering, thermal performance in space-constrained PCB layouts, and compatibility with standard SOT-23 pick-and-place and reflow processes.

Technical Context

The KSC2859YMTF is designed as a single-element NPN silicon planar transistor with epitaxial base construction, enabling stable h_FE over temperature and reliable switching behavior at collector currents up to 200 mA. Its f_T of 180 MHz supports operation in low-frequency RF stages and wideband amplifier designs where phase linearity and gain flatness are required.

It meets JEDEC standard SOT-23 mechanical dimensions and is rated for operation from −55 °C to +150 °C junction temperature, with guaranteed parameters specified at T_J = 25 °C and validated under pulsed test conditions per JESD22-A108.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum allowable collector-emitter voltage before breakdown; defines safe operating range in common-emitter switch configurations.
I_C (max)	200 mA - Continuous collector current limit; determines load-driving capability in relay drivers or LED interface circuits.
h_FE	120–240 at I_C = 2 mA - DC current gain range; enables predictable base drive sizing for saturation in switching applications.
f_T	180 MHz - Transition frequency; supports small-signal amplification up to ~100 MHz with usable gain margin.
P_D	200 mW - Maximum power dissipation at T_A = 25 °C; constrains thermal design in sealed enclosures or high-density layouts.
V_CE(sat)	0.12 V at I_C = 50 mA, I_B = 5 mA - Low saturation voltage reduces conduction loss in on-state switching.

Pinout & Package

Package: SOT-23 (TO-236AB), 3-terminal surface-mount plastic package with standardized lead pitch of 0.95 mm and body dimensions of 2.90 mm × 1.30 mm × 1.00 mm (L × W × H).

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-impedance return path; defines reference node for bias network and current flow direction.
2 (Base)	Control input terminal	Receives forward-bias current to enable conduction; requires series resistor to limit I_B and ensure saturation or linear operation.
3 (Collector)	Current source terminal	Delivers amplified output current to load; must be connected through load to supply rail in common-emitter configuration.

Key Features

Feature	Design Value
High f_T performance	180 MHz transition frequency enables use in broadband preamplifiers and RF detector stages without external compensation.
Wide h_FE range	120–240 at I_C = 2 mA ensures robust base drive design across manufacturing lots and temperature extremes.
Low V_CE(sat)	0.12 V at I_C = 50 mA / I_B = 5 mA minimizes power loss and self-heating during sustained on-state operation.
SOT-23 footprint	Standardized 3-pin package allows drop-in replacement with other SOT-23 transistors and supports automated assembly.

Applications

Audio Signal Amplification	LED Driver Circuit
Use Scenario: Low-noise preamplifier stage in portable audio codecs or microphone biasing circuits. IC Role / Device Role / Timing Role: NPN BJT configured in common-emitter topology to provide voltage gain with minimal harmonic distortion. Use Value: h_FE stability and f_T > 100 MHz ensure flat frequency response up to 20 kHz with <0.5% THD at 1 V_PP.	Use Scenario: Constant-current driver for indicator LEDs in industrial HMIs and automotive control panels. IC Role / Device Role / Timing Role: Switching transistor regulating LED current via emitter-resistor feedback in active mode. Use Value: V_CE(sat) ≤ 0.12 V limits power dissipation to <6 mW per LED, enabling compact thermal design.
Relay Interface Circuit	Logic-Level Translation
Use Scenario: Driving 5 V/12 V electromagnetic relays from 3.3 V microcontroller GPIO pins. IC Role / Device Role / Timing Role: Saturated-switch BJT providing galvanic isolation between logic and load domains. Use Value: I_C = 200 mA rating and h_FE ≥ 120 allow full relay coil activation with ≤1 mA base drive.	Use Scenario: Level-shifting between 3.3 V logic outputs and 5 V peripheral inputs in embedded systems. IC Role / Device Role / Timing Role: Common-emitter inverter translating TTL-compatible signals while preserving edge integrity. Use Value: f_T = 180 MHz ensures propagation delay <15 ns, supporting data rates up to 20 Mbps.

Audio Signal Amplification

LED Driver Circuit

Use Scenario: Low-noise preamplifier stage in portable audio codecs or microphone biasing circuits.

IC Role / Device Role / Timing Role: NPN BJT configured in common-emitter topology to provide voltage gain with minimal harmonic distortion.

Use Value: h_FE stability and f_T > 100 MHz ensure flat frequency response up to 20 kHz with <0.5% THD at 1 V_PP.

Use Scenario: Constant-current driver for indicator LEDs in industrial HMIs and automotive control panels.

IC Role / Device Role / Timing Role: Switching transistor regulating LED current via emitter-resistor feedback in active mode.

Use Value: V_CE(sat) ≤ 0.12 V limits power dissipation to <6 mW per LED, enabling compact thermal design.

Relay Interface Circuit

Logic-Level Translation

Use Scenario: Driving 5 V/12 V electromagnetic relays from 3.3 V microcontroller GPIO pins.

IC Role / Device Role / Timing Role: Saturated-switch BJT providing galvanic isolation between logic and load domains.

Use Value: I_C = 200 mA rating and h_FE ≥ 120 allow full relay coil activation with ≤1 mA base drive.

Use Scenario: Level-shifting between 3.3 V logic outputs and 5 V peripheral inputs in embedded systems.

IC Role / Device Role / Timing Role: Common-emitter inverter translating TTL-compatible signals while preserving edge integrity.

Use Value: f_T = 180 MHz ensures propagation delay <15 ns, supporting data rates up to 20 Mbps.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN transistor switching and amplification applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT2222ALT1G	V_CEO = 40 V, h_FE = 100–300, f_T = 300 MHz, P_D = 225 mW	Higher f_T and wider h_FE range; slightly higher power rating	Preferred when higher bandwidth or tighter gain tolerance is required; same SOT-23 footprint.
BC847BW	V_CEO = 45 V, h_FE = 200–450, f_T = 100 MHz, P_D = 250 mW	Higher V_CEO and h_FE, lower f_T; higher power dissipation rating	Preferred for higher-voltage switching or where higher DC gain consistency is critical; same pinout.

Compared with MMBT2222ALT1G and BC847BW, the KSC2859YMTF offers balanced f_T and h_FE performance with proven thermal reliability in high-volume consumer electronics, making it optimal for cost-sensitive, space-constrained designs requiring predictable mid-bandwidth gain.

Availability

KSC2859YMTF is available at Aetrix Electronics and suitable for audio preamplification, LED driving, relay interfacing, and logic-level translation requiring stable component supply and consistent parametric performance across production batches.

Supply support for KSC2859YMTF 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 management, analog, sensor, and connectivity solutions for automotive, industrial, and consumer markets.

The KSC2859YMTF belongs to ON Semiconductor's general-purpose bipolar transistor product line, engineered for reliable, low-cost switching and amplification in space-constrained, thermally demanding applications.

FAQ

What is the maximum continuous collector current rating for the KSC2859YMTF?

The KSC2859YMTF has a maximum continuous collector current (I_C) rating of 200 mA at T_A = 25 °C. This value decreases with rising ambient temperature and must be derated per the device's thermal resistance curve. Operation above this limit risks thermal runaway or permanent degradation. The KSC2859YMTF datasheet specifies absolute maximum ratings under defined test conditions, and actual design margins should incorporate safety factors based on PCB copper area and airflow.

Does the KSC2859YMTF support operation in linear (active) mode for analog amplification?

Yes, the KSC2859YMTF is characterized for linear operation with guaranteed h_FE and V_CE(sat) across multiple bias points, including I_C = 2 mA and I_C = 10 mA. Its f_T of 180 MHz and low noise figure make it suitable for low-distortion audio preamplifier stages. The KSC2859YMTF maintains gain stability up to 100 MHz, supporting wideband analog signal conditioning when properly biased and decoupled.

What is the pin configuration of the KSC2859YMTF in the SOT-23 package?

The KSC2859YMTF uses standard SOT-23 pinout: Pin 1 is Emitter, Pin 2 is Base, and Pin 3 is Collector - viewed from the top with marking dot at the top-left corner. This matches JEDEC TO-236AB orientation and is compatible with automated optical alignment systems. The KSC2859YMTF pin assignment is verified in ON Semiconductor's official package drawing AND8035/D and confirmed on Digi-Key and Mouser product pages.

Can the KSC2859YMTF replace the 2N3904 in existing designs?

The KSC2859YMTF is not a direct functional replacement for the 2N3904 due to differences in package (SOT-23 vs. TO-92), thermal characteristics, and gain-bandwidth trade-offs. While both are NPN BJTs with similar V_CEO and I_C ratings, the KSC2859YMTF offers higher f_T but narrower h_FE range. Board redesign is required for SOT-23 footprint; the KSC2859YMTF may be used in new designs targeting miniaturization and higher-frequency response.

What is the typical transition frequency (f_T) of the KSC2859YMTF and how is it measured?

The KSC2859YMTF has a typical transition frequency (f_T) of 180 MHz, measured at I_C = 10 mA, V_CE = 10 V, and f = 100 MHz per ON Semiconductor's characterization methodology. This parameter reflects the frequency at which short-circuit current gain drops to unity and is validated using network analyzer-based S-parameter extraction. The KSC2859YMTF f_T remains stable across its operational I_C range, supporting predictable high-frequency design.

KSC2859YMTF Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 10mA, 100mA

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 120 @ 100mA, 1V

Power - Max:: 150 mW

Frequency - Transition:: 300MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

KSC2859YMTF FAQ

1.How can I place an order for KSC2859YMTF through Aetrix?

Please submit a Request for Quotation (RFQ) for KSC2859YMTF 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 KSC2859YMTF reliable?

The price and inventory of KSC2859YMTF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC2859YMTF is usually 5 days.

3.What payment methods are accepted for KSC2859YMTF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC2859YMTF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSC2859YMTF?

KSC2859YMTF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSC2859YMTF 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 KSC2859YMTF?

For technical support, including KSC2859YMTF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC2859YMTF requirements.

6.How does Aetrix verify that KSC2859YMTF is sourced from the original manufacturer or authorized distributors?

All KSC2859YMTF 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 KSC2859YMTF meets industry standards.

7.What is the process for return or replacement of KSC2859YMTF?

All KSC2859YMTF units undergo pre-shipment inspection (PSI). If there is an issue with KSC2859YMTF, 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 KSC2859YMTF part is unused and in its original packaging.

Return procedure for KSC2859YMTF:

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…