onsemi KSD363YTU

Overview

KSD363YTU from ON Semiconductor is an NPN epitaxial silicon power transistor designed for horizontal deflection output in black-and-white TV systems, featuring VCBO = 300 V, VCEO = 120 V, IC = 6 A, PC = 40 W at TC = 25°C, and hFE = 40–240 (classified R/O/Y), with TO-220 package and integrated heat sink mounting capability.

For engineers reviewing the KSD363YTU datasheet, pinout, applications, or equivalent options, key selection criteria include high-voltage switching capability (300 V CB), robust continuous current handling (6 A), low saturation voltage (VCE(sat) = 1 V @ IC = 1 A, IB = 0.1 A), thermal performance under horizontal deflection duty cycles, and compatibility with legacy B/W TV flyback driver topologies.

Technical Context

The KSD363YTU operates as a high-voltage, medium-power NPN switch optimized for repetitive pulse operation in horizontal deflection circuits. Its 300 V collector-base breakdown rating supports safe flyback voltage margin, while its 120 V collector-emitter rating aligns with standard B/W TV line scan supply rails.

Designed for linear-to-saturated transition control, it delivers fT = 10 MHz at VCE = 5 V, IC = 0.5 A, enabling stable switching up to ~15.734 kHz line frequency with minimal phase lag. The device's SOA curve (Figure 5) explicitly validates safe operation in horizontal deflection output configurations with peak collector current up to 40 A and VCB up to 300 V.

Key Specifications

Pinout & Package

Package: TO-220 (standard through-hole, single-ended heat sink mount, lead-free plating per datasheet revision). Dimensions match Fairchild/ON Semiconductor TO-220 mechanical drawing (15.90 mm × 10.08 mm × 4.50 mm height, 2.54 mm lead pitch).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD363T4G and 2SC5200, the KSD363YTU provides optimal balance of VCBO margin (300 V), validated deflection SOA, and factory hFE classification-making it the preferred choice for legacy B/W TV repair and CRT-based industrial display maintenance where design intent and thermal constraints match the original specification.

Availability

KSD363YTU is available at Aetrix Electronics and suitable for B/W TV repair, CRT monitor refurbishment, and legacy analog video equipment maintenance requiring stable component supply and long-term obsolescence mitigation.

Supply support for KSD363YTU 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 (formerly Fairchild Semiconductor) is a global semiconductor supplier specializing in power management, analog, sensor, and discrete devices for automotive, industrial, and consumer applications.

The KSD363YTU belongs to ON Semiconductor's legacy high-voltage bipolar transistor product line, engineered specifically for horizontal deflection and flyback switching in analog CRT-based video systems.

FAQ

What is the maximum safe collector-emitter voltage for KSD363YTU in continuous DC operation?

The KSD363YTU has a rated VCEO of 120 V under DC conditions with IB = 0. This value is absolute maximum and must not be exceeded in any continuous or pulsed application. Derating is required above 25°C ambient, and actual safe operating voltage depends on simultaneous current, duty cycle, and heatsinking-refer to the SOA curve (Figure 5) for pulsed conditions. The KSD363YTU is not rated for >120 V VCEO regardless of external circuit protection.

Does KSD363YTU support pin-to-pin replacement for older Fairchild KSD363 variants?

Yes, the KSD363YTU maintains identical TO-220 pinout (Base–Collector–Emitter), mechanical dimensions, and electrical specifications as the original Fairchild KSD363 series. The "YTU" suffix denotes ON Semiconductor's post-integration marking convention; no PCB layout changes are needed when replacing legacy KSD363 units with KSD363YTU in field repair or production.

What hFE classification does KSD363YTU carry, and how does it affect bias design?

The KSD363YTU is factory classified into R (hFE = 40–80), O (70–140), or Y (120–240) bins. This classification is marked on the device body and determines required base drive current for saturation. For example, an R-bin unit needs ~0.125 A IB to saturate at IC = 1 A, whereas a Y-bin unit achieves same saturation with ~0.05 A IB-enabling optimized driver stage efficiency and thermal management in KSD363YTU-based designs.

Can KSD363YTU be used in modern switch-mode power supplies (SMPS)?

The KSD363YTU is not recommended for general-purpose SMPS due to its relatively low fT (10 MHz) and lack of optimized switching characteristics such as fast storage time or low Cobo. It was engineered for 15.734 kHz horizontal deflection-not high-frequency PWM. While it may function in low-frequency (<50 kHz), low-power SMPS, dedicated MOSFETs or modern bipolar transistors like the NSS12201LT1G offer superior efficiency, speed, and SOA control for KSD363YTU-replacement SMPS applications.

Is KSD363YTU RoHS-compliant and lead-free?

Yes, the KSD363YTU is manufactured with lead-free terminations and complies with RoHS Directive 2011/65/EU. ON Semiconductor confirms this in their official product change notices and packaging documentation. The TO-220 package uses matte tin plating over copper leads, and the device carries the "Pb-Free" marking per ON Semiconductor's standard labeling practice for RoHS-compliant parts-including KSD363YTU.