onsemi KSD526Y

Overview

KSD526Y 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; it delivers h_FE of 40–240 (class Y), V_CE(sat) ≤ 1.5 V at I_C = 3 A/I_B = 0.3 A, and f_T up to 8 MHz-used in linear and switching power amplifier stages.

For engineers reviewing the KSD526Y datasheet, pinout, applications, or equivalent options, key selection factors include its 80 V breakdown rating, 4 A continuous collector current capability, thermal performance in TO-220-3LD, h_FE classification Y (120–240), and saturation voltage behavior under high-current drive conditions.

Technical Context

This device operates as a medium-power NPN bipolar junction transistor optimized for linear amplification and switching in audio and DC power stages. Its safe operating area supports pulsed currents up to 10 A with appropriate derating, and its f_T of 3–8 MHz enables stable operation in low-to-mid frequency amplifier designs.

The KSD526Y exhibits V_BE(on) of 1.0–1.5 V at I_C = 3 A, enabling predictable base drive requirements, and C_cb = 90 pF at V_CB = 10 V ensures manageable Miller capacitance in common-emitter configurations.

Key Specifications

Pinout & Package

Package: TO-220-3LD (Case 340AT), through-hole, insulated tab, 3-terminal configuration with integral heatsink mounting surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD127G and KSC2690Y, the KSD526Y offers balanced trade-offs: sufficient 80 V rating for most 48 V systems, highest power handling (30 W), and tight h_FE spread (120–240) ideal for matched-pair audio output stages.

Availability

KSD526Y is available at Aetrix Electronics and suitable for audio power amplifiers, DC motor drivers, linear voltage regulators, and SMPS gate driver stages requiring stable component supply and Pb-free compliance.

Supply support for KSD526Y 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 specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The KSD526Y belongs to onsemi's discrete power transistor product line, designed specifically for medium-power linear and switching applications demanding reliable gain, rugged voltage ratings, and thermally robust packaging.

FAQ

What is the maximum continuous collector current rating for KSD526Y?

The KSD526Y is rated for 4 A continuous collector current (I_C) at case temperature T_C = 25°C. This rating decreases linearly with rising case temperature per the power derating curve in Figure 6 of the datasheet, reaching zero at T_C = 175°C. For sustained operation above 25°C, heatsinking must be applied to maintain T_C within limits. The KSD526Y can handle short pulses up to 10 A as shown in the Safe Operating Area graph.

Is KSD526Y pin-compatible with KSB596?

No, the KSD526Y is an NPN transistor while the KSB596 is its complementary PNP counterpart; they share identical TO-220-3LD packaging and pinout (Base–Collector–Emitter), but opposite polarity means they cannot substitute directly. Both are intended for use together in push-pull or complementary symmetry amplifier stages. The KSD526Y pinout is Base (pin 1), Collector (pin 2), Emitter (pin 3).

What does the 'Y' suffix indicate in KSD526Y?

The 'Y' suffix in KSD526Y denotes h_FE classification per the datasheet's h_FE CLASSIFICATION table: devices marked Y have a guaranteed DC current gain range of 120–240 at V_CE = 5 V and I_C = 3 A. This tighter gain band improves predictability in bias-critical applications like audio output stages compared to R (40–80) or O (70–140) variants.

Does KSD526Y require a heatsink in normal operation?

Yes, the KSD526Y requires a heatsink for any application approaching its 30 W power dissipation limit at T_C = 25°C. Even at moderate power levels (e.g., 10 W), thermal resistance from junction-to-case (R_θJC) and case-to-ambient (R_θCA) must be managed to prevent exceeding the 150°C maximum junction temperature. The TO-220-3LD package features an insulated tab to enable direct mounting to grounded heatsinks without electrical isolation hardware.

What is the typical V_CE(sat) value for KSD526Y under full load?

The KSD526Y specifies V_CE(sat) ≤ 1.5 V at test conditions of I_C = 3 A and I_B = 0.3 A (i.e., forced β = 10). Typical values observed in characterization are approximately 0.45–0.8 V under these conditions. This saturation voltage directly determines conduction losses (P_cond = V_CE(sat) × I_C) and must be verified at actual operating I_B/I_C ratios, as V_CE(sat) rises significantly if base drive is insufficient.