onsemi 2SC3256R

Overview

2SC3256R from SANYO is an NPN epitaxial planar silicon power transistor designed for high-speed switching in demanding DC-DC converters, strobe flash circuits, and motor control amplifiers. It delivers 15 A collector current, 60 V C-E breakdown voltage, and low 0.4 V saturation voltage at IC = 7.5 A/IB = 375 mA - enabling efficient high-power switching in compact industrial inverters.

For engineers reviewing the 2SC3256R datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-3PB package thermal performance (80 W @ Tc = 25°C), fT = 100 MHz at IC = 1 A, fast turn-on/off times (1.0 µs / 5.0 µs), and guaranteed hFE range of 140–280 at IC = 1 A.

Technical Context

The 2SC3256R operates as a high-current, medium-voltage NPN switch with optimized charge storage and minority-carrier lifetime control for rapid transition between saturation and cutoff. Its epitaxial planar structure ensures stable hFE across IC = 0.01–10 A and supports reliable operation up to TJ = 150°C.

Designed for hard-switching topologies, it features low VCE(sat) with tight distribution (≤0.4 V at IC/IB = 20), robust secondary breakdown immunity (ASO curves validated for 1 ms–100 ms pulses), and symmetrical SOA limits for both DC and pulsed conditions - critical for flyback and half-bridge driver stages.

Key Specifications

Pinout & Package

SANYO TO-3PB metal package: isolated collector tab, 3-pin through-hole mounting, 15.6 mm × 14.0 mm footprint, 4.8 mm height, integral mounting hole. Thermal resistance θJC = 1.56°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD127G and 2SC5200, the 2SC3256R uniquely balances 15 A current capability, 60 V rating, 100 MHz fT, and TO-3PB thermal performance - making it optimal for compact, high-efficiency 50–200 kHz switching stages where gain linearity and SOA margin are critical.

Availability

2SC3256R is available at Aetrix Electronics and suitable for fluorescent lamp ballasts, DC motor controllers, and strobe flash circuits requiring stable component supply and long-term industrial availability.

Supply support for 2SC3256R 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

SANYO Electric Co., Ltd. was a Japanese semiconductor manufacturer specializing in power discrete devices, analog ICs, and optoelectronics before its acquisition by Panasonic in 2011; known for rugged, thermally optimized transistor designs.

The 2SC3256R belongs to SANYO's high-speed power transistor family engineered specifically for industrial switching applications including inverters, lamp drivers, and motor controls - emphasizing SOA robustness, gain consistency, and thermal reliability.

FAQ

What is the maximum junction temperature specification for the 2SC3256R?

The 2SC3256R has a maximum junction temperature (TJ) rating of +150°C. This limit applies under all operating conditions, including pulsed and DC modes. Operation beyond this temperature risks permanent degradation of hFE and increased leakage current. Derating curves in the official SANYO datasheet (No.2370-3/4) define allowable power dissipation versus case temperature - for example, at TC = 100°C, maximum PC drops to ~32 W. Always mount the 2SC3256R on a properly sized heatsink with thermal interface material to maintain TJ ≤ 150°C.

Does the 2SC3256R have a built-in base-emitter resistor or protection diode?

No, the 2SC3256R is a bare NPN bipolar junction transistor with no integrated base-emitter resistor or clamp diode. It requires external base current limiting and, in inductive load applications, an external flyback diode across the collector-emitter or load. The device relies on proper external circuit design for safe operation - especially during turn-off transients. This architecture gives designers full control over base drive dynamics but mandates careful attention to drive strength and snubbing in high-dI/dt environments where the 2SC3256R is commonly deployed.

Can the 2SC3256R be used as a direct replacement for the 2SC5200 in audio amplifier output stages?

No, the 2SC3256R is not a direct replacement for the 2SC5200 in audio amplifier output stages. While both use TO-3PB packages and are NPN transistors, the 2SC5200 has VCEO = 230 V and is optimized for linear Class AB operation with lower fT (30 MHz) and different SOA contours. The 2SC3256R's 60 V rating and 100 MHz fT make it unsuitable for high-voltage audio rails (>80 V), and its SOA is tuned for switching, not sustained linear dissipation. Using the 2SC3256R in place of the 2SC5200 risks premature failure under typical audio amplifier bias and load conditions.

What is the typical VBE(on) value for the 2SC3256R at IC = 10 A?

The typical base-emitter voltage (VBE) for the 2SC3256R at IC = 10 A and IB = 500 mA is –0.95 V (measured at 25°C). This value is derived from the IC–VBE curve (ITR03208) in the official SANYO datasheet No.2370-2/4, which shows VBE ≈ –0.95 V at IC = 10 A for the 2SC3256R variant. Note that VBE decreases slightly with rising junction temperature - approximately –2.1 mV/°C - so actual VBE in operation will vary with thermal conditions. Accurate bias network design for the 2SC3256R must account for this temperature coefficient and the specified hFE tolerance band.

Is the 2SC3256R RoHS compliant and lead-free?

The original 2SC3256R was manufactured prior to RoHS enforcement (pre-2006) and is not inherently RoHS compliant - it contains lead in the solderable leads and die attach. SANYO did not issue a Pb-free variant of the 2SC3256R before discontinuation. For new designs requiring RoHS compliance, consider modern alternatives such as the ON Semiconductor MJD127G (RoHS-compliant TO-220) or STMicroelectronics BDW32C (RoHS TO-3), while verifying SOA, gain, and switching performance against the 2SC3256R's published specs. Aetrix Electronics can provide legacy 2SC3256R with full traceability for repair or legacy system support.