onsemi KSC5502TU

Overview

KSC5502TU from ON Semiconductor (formerly Fairchild) is a high-voltage NPN planar silicon power transistor in TO-220 package, rated for 1200 V collector-base voltage, 600 V collector-emitter voltage, and 2 A DC collector current. It delivers 50 W collector dissipation at TC = 25°C with 2.5 °C/W junction-to-case thermal resistance, and is engineered for electronic ballast and high-voltage switch-mode applications requiring wide safe operating area and low storage time variance.

For engineers reviewing the KSC5502TU datasheet, pinout, applications, or equivalent options, key selection criteria include avalanche energy rating (2.5 mJ), dynamic saturation voltage under inductive switching (e.g., 8–23 V at 1–3 μs), and guaranteed hFE range (15–40 at IC = 0.2 A, VCE = 1 V, 25°C), critical for reliable gate drive design in fluorescent lamp ballasts and industrial SMPS.

Technical Context

This device employs a planar epitaxial structure optimized for high-voltage blocking and fast switching in resistive and inductive load configurations. Its design supports forced gain operation (IC/IB = 5 or 10) with validated turn-on/off times - e.g., tON ≤ 450 ns and tOFF ≤ 5.0 μs at IC = 1 A, TC = 25°C - under 300 V supply and 300 Ω load.

Thermal performance is defined by RθJC = 2.5 °C/W and RθJA = 85 °C/W, enabling stable operation up to TJ = 150°C. Input/output capacitances (Cib = 410–500 pF, Cob = 20–100 pF at f = 1 MHz) are specified to support snubberless or minimally snubbed high-frequency switching topologies.

Key Specifications

Pinout & Package

Package: TO-220 (JEDEC variation AB), molded, 3-lead, through-hole. Case is electrically connected to Collector.

Key Features

Applications

Equivalent & Alternatives

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

Compared with FJP5502 and MJD5502, the KSC5502TU provides the highest thermal efficiency (RθJC = 2.5 °C/W), largest continuous power capability (50 W), and most consistent storage time behavior - making it the optimal choice for high-volume, thermally demanding electronic ballast and industrial SMPS designs.

Availability

KSC5502TU is available at Aetrix Electronics and suitable for fluorescent lamp ballasts, industrial AC-DC power supplies, and high-voltage DC motor control requiring stable component supply, long-term lifecycle continuity, and traceable sourcing.

Supply support for KSC5502TU 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 manufacturer specializing in power management, analog, sensor, and discrete solutions for automotive, industrial, and consumer markets.

The KSC5502TU belongs to ON Semiconductor's high-voltage bipolar power transistor product line, designed specifically for energy-efficient electronic ballasts, industrial switch-mode power conversion, and ruggedized high-voltage switching applications.

FAQ

What is the maximum junction temperature rating for the KSC5502TU?

The KSC5502TU has a maximum junction temperature (TJ) rating of 150°C, verified per Absolute Maximum Ratings table. This allows operation in high-ambient environments such as enclosed lighting fixtures or industrial enclosures, provided thermal design maintains TJ ≤ 150°C using the specified RθJC = 2.5 °C/W and appropriate heatsinking. Derating begins above TC = 25°C per Figure 22.

Does the KSC5502TU have avalanche ruggedness, and how is it specified?

Yes, the KSC5502TU is rated for single-pulse avalanche energy (EAS) of 2.5 mJ at TJ = 25°C, measured under standardized test conditions (pulse width = 5 ms, duty cycle ≤ 10%). This specification confirms its ability to absorb inductive flyback energy without failure in unclamped switching topologies - a key requirement in electronic ballast and flyback converter designs.

What is the pin configuration of the KSC5502TU in the TO-220 package?

The KSC5502TU uses standard TO-220 pinout: Pin 1 = Base, Pin 2 = Collector (connected to the metal tab/case), Pin 3 = Emitter. This configuration is confirmed in the "Equivalent Circuit" diagram and "Physical Dimensions" section (Figure 23) of the official datasheet. The collector-tab connection mandates electrical isolation from the heatsink unless the system design intentionally references collector to ground.

How does the KSC5502TU perform in inductive switching applications?

In inductive load switching (VCC = 15 V, VZ = 300 V, LC = 200 μH), the KSC5502TU achieves tSTG = 1.4–2.0 μs (IC = 0.4 A) and tF = 130–200 ns (25°C), with cross-over time tC = 210–350 ns. These values are validated per datasheet Table on page 3 and Figures 12–17, confirming suitability for resonant and quasi-resonant ballast drivers where precise timing control is essential.

Is the KSC5502TU suitable for use in life support or medical devices?

No - the KSC5502TU is explicitly excluded from life support or FDA Class 3 medical device applications per ON Semiconductor's Life Support Policy. It is not designed, intended, or authorized for use as a critical component in systems where failure could result in injury or death. For such applications, consult ON Semiconductor's dedicated medical-grade product portfolio and obtain written approval prior to use.