onsemi KSD568RTU

Overview

KSD568RTU from ON Semiconductor (formerly Fairchild) is an NPN epitaxial silicon power transistor in TO-220 package, rated for 60 V V_CEO, 7 A DC collector current, and 40 W collector dissipation at T_C = 25°C, used in low-frequency power amplification and industrial switching applications.

For engineers reviewing the KSD568RTU datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO = 60 V, I_C = 7 A, h_FE ≥ 40 at I_C = 3 A, V_CE(sat) ≤ 0.5 V at I_C = 5 A / I_B = 0.5 A, and TO-220 thermal performance under forced-air or heatsink conditions.

Technical Context

The KSD568RTU operates as a medium-power, low-speed switching and linear amplification device with fixed NPN polarity and complementary pairing to KSB707/KSB708 PNP transistors. Its safe operating area (SOA) is defined up to 10 ms pulse width with derating above 25°C case temperature.

It features h_FE classification ranging 40–200 depending on grade (R/O/Y), V_BE(sat) = 1.5 V at I_C = 5 A / I_B = 0.5 A, and junction temperature limit of 150°C - enabling use in non-high-frequency industrial control stages where gain stability and saturation voltage are design-critical.

Key Specifications

Pinout & Package

Package: TO-220 (3-lead, straight lead, insulated tab). Mounting surface is electrically connected to collector. Standard JEDEC TO-220 outline with 2.54 mm lead pitch and 15.90 mm body length.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD127G and TIP3055, the KSD568RTU offers tighter h_FE control (40–200), lower V_CE(sat), and TO-220 compatibility with proven industrial heritage - making it optimal for cost-sensitive, medium-power linear amplifier and relay driver designs requiring predictable gain and thermal behavior.

Availability

KSD568RTU is available at Aetrix Electronics and suitable for audio power amplifiers, industrial relay drivers, motor start circuits, and linear DC power supply regulator stages requiring stable component supply and long-term industrial availability.

Supply support for KSD568RTU 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 (acquired Fairchild Semiconductor in 2016) is a global supplier of energy-efficient semiconductor components for automotive, industrial, cloud computing, and IoT applications.

The KSD568RTU belongs to Fairchild's legacy low-frequency power transistor family, designed specifically for robust, thermally stable operation in industrial control, audio amplification, and discrete power conversion circuits.

FAQ

What is the maximum continuous collector current rating for KSD568RTU?

The KSD568RTU has a maximum DC collector current rating of 7 A at T_C = 25°C. Derating is required above this temperature - for example, at T_C = 100°C, the usable I_C drops to approximately 2.8 A per the power derating curve in the datasheet. The KSD568RTU must be mounted on an appropriate heatsink to sustain this rating in real-world conditions.

Is KSD568RTU pin-compatible with KSD569RTU?

No, KSD568RTU and KSD569RTU are not pin-compatible replacements - they share identical TO-220 package and pinout (Base–Collector–Emitter), but differ in V_CEO rating (60 V vs. 80 V) and h_FE distribution. Substituting KSD569RTU for KSD568RTU may be acceptable in higher-voltage designs, but KSD568RTU must not be used where 80 V V_CEO is required. Both devices retain identical KSD568RTU physical mounting and electrical interface.

What is the typical h_FE range for KSD568RTU at I_C = 5 A?

At I_C = 5 A and V_CE = 1 V, the KSD568RTU exhibits h_FE values between 20 and 100 depending on grade (R/O/Y classification). The "Y" grade guarantees h_FE ≥ 100, while "R" grade starts at 40. This variation directly affects base drive requirements - for example, achieving 5 A collector current with "R" grade demands ≥125 mA base current, whereas "Y" grade needs only ~50 mA. The KSD568RTU datasheet specifies these ranges in its h_FE classification table.

Can KSD568RTU be used in switching power supplies?

The KSD568RTU is not optimized for high-frequency switching power supplies due to its relatively slow switching speed and lack of specified t_f/t_r or storage time. It is explicitly characterized for low-speed industrial switching and linear amplification. While it can function in low-kHz hard-switched topologies (e.g., <5 kHz inverters), its V_CE(sat) and SOA make it better suited for relay/motor control than SMPS. For such uses, the KSD568RTU should be evaluated against safe operating area limits under actual waveform conditions.

Does KSD568RTU have built-in ESD or overvoltage protection?

No, the KSD568RTU is a bare silicon bipolar junction transistor without integrated ESD protection diodes or overvoltage clamping. External protection - such as base-emitter resistors, flyback diodes across inductive loads, and TVS devices on collector lines - is mandatory in practical designs. The absolute maximum ratings define only survivability limits (e.g., V_CBO = 100 V), not functional protection. Designers must implement external safeguards to ensure reliable KSD568RTU operation in noisy industrial environments.