onsemi KSD526O

Overview

KSD526O from onsemi is an NPN epitaxial silicon power transistor in TO-220-3LD package, rated for 80 V V_CEO, 4 A I_C, and 30 W P_C at T_C = 25°C, with h_FE ranging 40–240 (class Y), used in linear power amplifier stages requiring high current gain and thermal robustness.

For engineers reviewing the KSD526O datasheet, pinout, applications, or equivalent options, key selection criteria include safe operating area (SOA) compliance at pulse/DC conditions, V_CE(sat) ≤ 1.5 V at I_C = 3 A / I_B = 0.3 A, and Pb-free TO-220-3LD mechanical compatibility with heatsink mounting.

Technical Context

This device operates as a medium-power NPN bipolar junction transistor optimized for Class AB linear amplification. Its design supports DC bias stability via h_FE classification (Y: 120–240), low V_BE(on) (1.0–1.5 V at I_C = 3 A), and f_T up to 8 MHz for audio-frequency signal handling.

The SOA curve defines operational limits across pulse width (1 ms to DC) and case temperature (25–150°C), while thermal derating begins at T_C > 25°C with linear reduction to zero dissipation at 175°C - critical for heatsink sizing in continuous-duty amplifiers.

Key Specifications

Pinout & Package

Package: TO-220-3LD (Case 340AT), through-hole, single-ended heatsink-mountable, with electrically isolated collector tab.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD127G and 2N3055G, KSD526O offers optimal balance of through-hole manufacturability, tight h_FE binning (Y-class), and SOA-defined pulse robustness - making it preferred for cost-sensitive, thermally managed audio and industrial linear amplifier designs.

Availability

KSD526O is available at Aetrix Electronics and suitable for audio power amplifiers, DC motor driver stages, linear voltage regulator pass elements, and industrial sensor excitation circuits requiring stable component supply and Pb-free compliance.

Supply support for KSD526O 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, delivering high-performance analog, logic, discrete, and power management solutions.

The KSD526O belongs to onsemi's general-purpose power bipolar transistor family, engineered for reliable linear amplification and switching in industrial, consumer audio, and power control applications.

FAQ

What is the maximum continuous collector current rating for KSD526O?

The KSD526O is rated for 4 A continuous collector current (I_C) at case temperature T_C = 25°C. Derating is required above this temperature per the power derating curve in Figure 6 of the datasheet, reaching zero dissipation at 175°C. Actual usable current depends on heatsink performance and ambient conditions.

Is KSD526O pin-compatible with KSB596?

No, KSD526O is not pin-compatible with KSB596. While they are complementary NPN/PNP devices intended for matched push-pull operation, KSD526O has Base–Collector–Emitter pinout (1–2–3), whereas KSB596 uses Emitter–Collector–Base (1–2–3) in the same TO-220-3LD package. Physical layout reversal must be accounted for in PCB design.

Does KSD526O meet RoHS requirements?

Yes, KSD526O is a Pb-free device compliant with the EU RoHS Directive 2011/65/EU. The "Y" suffix in ordering codes (e.g., KSD526Y) explicitly denotes Pb-free packaging, and the device uses lead-free terminations and internal construction verified per onsemi's qualification standards.

What is the typical V_CE(sat) for KSD526O under standard test conditions?

The typical V_CE(sat) for KSD526O is 0.7 V at I_C = 3 A and I_B = 0.3 A, with a maximum specified value of 1.5 V under those same conditions. This saturation voltage directly impacts conduction loss and thermal generation in linear or quasi-saturated operation modes.

Can KSD526O be used in switching applications?

KSD526O can be used in low-frequency switching applications (e.g., <100 kHz) where its f_T of 3–8 MHz and SOA allow safe turn-on/turn-off transitions. However, it is primarily optimized for linear amplification; for high-efficiency, high-speed switching, MOSFETs or dedicated switching transistors are recommended instead of KSD526O.