onsemi KSC4010RTU

Overview

KSC4010RTU from ON Semiconductor (formerly Fairchild) is an NPN epitaxial silicon power transistor designed for high-current audio amplifier output stages, featuring V_CEO = 120 V, I_C = 6 A DC, P_C = 60 W at T_C = 25°C, h_FE = 55–160, and TO-3P package with base-collector-emitter pinout. It operates in Class AB push-pull configurations for Hi-Fi and professional audio systems.

For engineers reviewing the KSC4010RTU datasheet, pinout, applications, or equivalent options, key selection criteria include safe operating area (SOA) robustness at high V_CE, low V_CE(sat) ≤ 2.5 V at I_C = 5 A / I_B = 0.5 A, f_T = 30 MHz bandwidth, and thermal derating compliance up to T_J = 150°C.

Technical Context

This device implements a planar epitaxial structure optimized for linear amplification, with specified SOA limits covering single nonrepetitive pulses (100 ms), DC, and 10 ms transient conditions. Its complementary pairing with KSA3010 enables balanced push-pull operation in bipolar audio output stages.

The transistor exhibits controlled gain dispersion (h_FE 55–110 for 'R' grade, 80–160 for 'O' grade), defined V_BE(on) ≤ 1.5 V at I_C = 5 A, and Cob = 90 pF at V_CB = 10 V - parameters critical for stability and frequency response in wideband audio designs.

Key Specifications

Pinout & Package

Package: TO-3P (isolated metal tab), thermally enhanced through-hole package with 15.6 mm × 19.9 mm footprint, 3.8 mm height, and screw-mount hole (Ø3.2 mm). Designed for direct heatsink attachment with electrical isolation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with KSC4010RTU, MJE15032G offers greater voltage headroom at the cost of less predictable gain matching, while 2SC5200 delivers substantially higher power capacity but demands more aggressive thermal management and driver strength - both require PCB layout review for pinout and thermal pad compatibility.

Availability

KSC4010RTU is available at Aetrix Electronics and suitable for Hi-Fi audio amplifiers, professional PA systems, instrument amplifier drivers, and industrial audio distribution requiring stable component supply across long-lifecycle production programs.

Supply support for KSC4010RTU 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 supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The KSC4010RTU belongs to Fairchild's legacy audio power transistor family, engineered specifically for high-fidelity linear amplification with emphasis on SOA integrity, thermal stability, and complementary pairing - targeting discrete amplifier design rather than switching applications.

FAQ

What is the maximum continuous collector current rating for KSC4010RTU?

The KSC4010RTU has a maximum continuous collector current (I_C) rating of 6 A at case temperature T_C = 25°C. This rating decreases with rising case temperature per the published derating curve - at T_C = 100°C, the usable I_C drops to approximately 3.5 A. The KSC4010RTU must be mounted on an adequately sized heatsink to sustain this current in real-world operation.

Is KSC4010RTU pin-compatible with KSA3010?

No, KSC4010RTU and KSA3010 are complementary devices (NPN vs. PNP) but not pin-compatible - KSC4010RTU uses Base-Collector-Emitter (1-2-3) pinout in TO-3P, while KSA3010 uses Base-Emitter-Collector (1-2-3). Physical mounting orientation and PCB layout must account for reversed emitter/collector terminals. The KSC4010RTU datasheet explicitly states it is "complement to KSA3010" for circuit function, not mechanical fit.

What is the safe operating area (SOA) behavior of KSC4010RTU under pulsed conditions?

The KSC4010RTU SOA is defined for three conditions: DC, 10 ms, and 100 ms single nonrepetitive pulses. At V_CE = 60 V, it supports up to ~5.5 A for 100 ms pulses, ~4.2 A for 10 ms, and ~2.8 A continuously. These boundaries prevent secondary breakdown and are validated per JEDEC JESD24 guidelines. The KSC4010RTU SOA chart in Figure 5 of its datasheet must be consulted for exact V_CE/I_C combinations.

Does KSC4010RTU require external base resistors in typical audio amplifier designs?

Yes, KSC4010RTU requires carefully calculated external base resistors to limit peak base current and ensure stable biasing. With h_FE ranging from 55 to 160 and needing ≥0.5 A base drive for full saturation at I_C = 5 A, resistor values must accommodate worst-case gain and thermal drift. The KSC4010RTU's V_BE(on) ≤ 1.5 V at I_C = 5 A informs forward-bias network design, especially in Darlington or compound configurations.

What is the junction-to-case thermal resistance (R_θJC) of KSC4010RTU?

The junction-to-case thermal resistance (R_θJC) of KSC4010RTU is 1.25°C/W, measured from die junction to the metal tab surface. This value assumes proper mounting with thermal interface material and sufficient clamping force. When combined with heatsink R_θCA, it determines total thermal path resistance - for example, with a 1.5°C/W heatsink, total R_θJA ≈ 2.75°C/W, limiting steady-state power dissipation to ~22 W at ΔT = 60°C. This R_θJC applies directly to the KSC4010RTU in TO-3P package.