The 2SC5200 transistor remains one of the most widely recognized power devices in audio engineering. A standard component in Class A, AB, and H amplifier architectures. This article will discuss the complete details about this device - from its pinout and specifications to its working principles, alternatives, and actual applications.

Catalog

2SC5200 Transistor Basic

The 2SC5200 from Toshiba is a high-power NPN BJT designed for demanding audio amplifier and power-switching applications. Known for its strong linearity, low distortion, and high reliability, it has become a preferred choice in Hi-Fi systems and professional sound equipment. Its ability to handle high current and power dissipation allows it to deliver clean, stable performance even under heavy loads.

This transistor also features a high transition frequency and durable construction, making it ideal for Class A, AB, and H amplifier output stages. When paired with its complementary PNP device, the 2SA1943, it forms a robust and widely adopted output pair for audio design engineers.

If you are interested in purchasing the 2SC5200, feel free to contact us for pricing and availability.

2SC5200 Transistor CAD Models

2SC5200 Transistor Pinout Configuration

2SC5200 Alternatives & Equivalents

• 2SC5242

• 2SC3858

• NJW0281G

• 2SC3281

• 2SC6145

• TIP41C/TIP3055

2SC5200 Transistor Specifications

2SC5200 Electrical Characteristics

2SC5200 Typical Characteristic Curves

I_C – V_CE (Collector Current vs. Collector-Emitter Voltage)

This graph shows how the collector current (IC) changes as the collector-emitter voltage (V_CE) increases, with each curve representing a different base current (IB). At low VCE, the curves rise steeply because the transistor is leaving saturation and entering its active region. As VCE increases further, each curve flattens, meaning the transistor is now operating in a stable amplification mode where IC is mainly controlled by IB rather than VCE. Higher base currents produce higher collector currents, demonstrating the transistor’s ability to deliver strong output current for audio amplifier stages.

I_C – V_BE (Collector Current vs. Base-Emitter Voltage)

This curve shows how the collector current responds to changes in the base-emitter voltage (V_BE) at different temperatures. As temperature increases, the required VBE to achieve the same IC decreases, which is typical of silicon BJTs. For example, at 100°C, the transistor conducts more current at a lower V_BE compared to –25°C. This temperature-dependent behavior highlights the importance of thermal compensation in amplifier circuits, because excessive temperature rise can cause higher current flow and potentially thermal runaway if not properly managed. The graph visually demonstrates how sensitive the 2SC5200 is to base voltage variations, especially in high-power applications.

V_CE(sat) – I_C (Saturation Voltage vs. Collector Current)

This graph displays the collector-emitter saturation voltage (V_CE(sat)) at various collector currents and temperatures. At low current levels, V_CE(sat) is small, meaning the transistor conducts efficiently with minimal voltage drop. As IC increases, the saturation voltage gradually rises, indicating more voltage is required to maintain conduction. Temperature also affects this behavior; lower temperatures generally result in a lower V_CE(sat), while higher temperatures increase it slightly. This characteristic is crucial in power amplifier and switching circuits, where excessive saturation voltage can lead to heat build-up and reduced efficiency.

h_FE – I_C (DC Current Gain vs. Collector Current)

This curve shows how the transistor’s DC current gain (h_FE) varies with collector current and temperature. The gain is highest in the mid-current region, typically between 1A and 5A, which is where audio power amplifiers operate most of the time. At very low and very high currents, h_FE decreases, indicating reduced amplification efficiency. Temperature also affects gain: at higher temperatures, the curves shift, generally providing a slightly reduced and more nonlinear gain. This information is essential for designing stable biasing networks because fluctuations in temperature or load current can change the transistor’s overall amplification characteristics. The graph highlights why matched transistor pairs and thermal compensation are important in high-fidelity audio designs.

2SC5200 Transistor Working in Circuit

2SC5200 as a High-Power Output Transistor in a Class-AB Audio Amplifier

In the first schematic, the 2SC5200 transistors are used in parallel pairs as the final power output stage of a high-power Class-AB audio amplifier. The circuit begins with a differential input stage (Q1 and Q2), which receives the audio signal and sets the basic gain and linearity. This feeds a voltage-amplification stage (VAS), usually formed by transistors such as the C2229 and TIP42/BD139 types, which greatly increases voltage swings before driving the output transistors. The 2SC5200 devices work together with their complementary PNP devices (e.g., 2SA1943 or equivalent positions, though not shown directly here-this diagram uses TIP/D718/K6688 combinations) to deliver large currents to the speaker while maintaining low distortion.

The paralleled 2SC5200 transistors share current through 0.33-ohm emitter resistors, preventing thermal runaway and ensuring equal load distribution. These transistors operate in Class-AB mode, biased slightly above cutoff via the diode-connected thermal compensation network and driver transistors, ensuring minimal crossover distortion. The output passes through an LC (coil + resistor) network to stabilize the amplifier and prevent high-frequency oscillation, especially with reactive speaker loads. In this configuration, the 2SC5200 functions as a rugged, linear, high-current device capable of delivering hundreds of watts into low-impedance loads.

2SC5200 as a Push-Pull Output Device with an Op-Amp Front End

In the second diagram, the 2SC5200 works as part of a push-pull power stage, this time driven by an operational amplifier (4558D). The op-amp handles the small-signal processing: it sets the gain, corrects nonlinearities, and feeds the driver transistors (TIP122 and TIP127). These drivers supply the necessary base current to fully drive the 2SC5200 and its PNP counterpart (TTA1943). The 2SC5200 here acts as the NPN half of the complementary pair, sourcing current to the load, while the PNP transistor sinks current, allowing for symmetric amplification.

The biasing network around the op-amp and drivers establishes the correct idle current so that the 2SC5200 transitions smoothly between conduction and cutoff. This prevents crossover distortion and ensures high-fidelity output. The feedback loop from the speaker output back to the op-amp input stabilizes the system and flattens frequency response, resulting in cleaner audio reproduction. In this architecture, the 2SC5200’s role is to provide current gain and power delivery, translating the small op-amp signal into a high-power output capable of driving speakers directly.