onsemi 2SD612KE

Overview

2SD612KE from SANYO is an NPN epitaxial planar silicon transistor rated for 35V V_CEO, 2A I_C, and 1W P_C at T_c=25°C, designed for low-frequency power amplifier stages in audio output circuits. It features h_FE = 20–100 at I_C = −500mA (for PNP counterpart), V_CE(sat) ≤ 1.2V at I_C/I_B = 10, and f_T = 100MHz, supporting Class AB push-pull configurations in consumer audio amplifiers.

For engineers reviewing the 2SD612KE datasheet, pinout, applications, or equivalent options, this page delivers verified electrical ratings, TO-126 package layout, real-world amplifier circuit integration data, thermal derating curves, and validated alternative transistors for audio power stage replacement or design continuity.

Technical Context

The 2SD612KE operates as a medium-power NPN switching and linear amplifier device with DC current gain (h_FE) binned across ranks (D/E/F) and specified at V_CE = 2V, I_C = −500mA. Its safe operating area (ASO) supports pulsed collector currents up to 3A, and its f_T of 100MHz enables stable operation into the upper audio band without high-frequency oscillation in properly compensated designs.

Thermal performance is defined by junction-to-case (T_j–T_c) and junction-to-ambient (T_j–T_a) limits: P_C = 1W at T_c = 25°C, derating linearly to zero at T_c = 150°C; maximum junction temperature is 150°C, with storage range from −55°C to +150°C. The device uses a standard TO-126 package with emitter-collector-base pinout (1–2–3).

Key Specifications

Pinout & Package

SANYO TO-126 package (JEDEC TO-126), 3-lead plastic power transistor with flat side facing viewer and leads downward: Pin 1 = Emitter, Pin 2 = Collector (tab-connected), Pin 3 = Base. Mounting tab is electrically connected to collector; isolation washer required when mounting to grounded heatsink.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN low-frequency power amplifier applications.

Compared with 2SD612KE, the 2SD612K offers guaranteed h_FE matching for complementary symmetry, while the MJD127G provides higher voltage/current headroom at the cost of board space and thermal management complexity-neither is pin-compatible without layout revision.

Availability

2SD612KE is available at Aetrix Electronics and suitable for consumer audio amplifiers, automotive infotainment output stages, and discrete power transistor replacement programs requiring stable component supply and long-term obsolescence mitigation.

Supply support for 2SD612KE 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 analog and power discrete devices, known for high-reliability audio transistors and optoelectronics before its acquisition by Panasonic in 2012.

The 2SD612KE belongs to SANYO's low-frequency power transistor family engineered specifically for high-fidelity audio amplifier output stages, emphasizing wide ASO, thermal stability, and gain consistency across production lots.

FAQ

What is the maximum collector-emitter voltage rating for the 2SD612KE?

The 2SD612KE has a maximum collector-emitter voltage rating (V_CEO) of 35V. This value is absolute-exceeding it, even momentarily, risks avalanche breakdown and permanent device failure. In practice, designs should maintain V_CE ≤ 28V under peak signal conditions to ensure margin, especially in transformer-coupled or capacitive-coupled output topologies where flyback voltages may occur. The 2SD612KE datasheet (No.341) confirms this rating at T_a = 25°C.

Does the 2SD612KE have a built-in protection diode or thermal shutdown feature?

No, the 2SD612KE is a bare silicon NPN bipolar junction transistor with no integrated protection diodes, thermal sensors, or shutdown circuitry. It relies entirely on external design safeguards-such as emitter degeneration resistors, base current limiting, SOA-aware biasing, and heatsink-mounted thermistors-to prevent secondary breakdown or thermal runaway. This is consistent with all transistors in SANYO's 2SD612 series, as confirmed in the "Features" section of the official datasheet No.341.

Can the 2SD612KE be used as a direct replacement for the 2SD612 without modification?

Yes, the 2SD612KE is functionally and mechanically identical to the base 2SD612, sharing the same TO-126 package, pinout (E-C-B), absolute maximum ratings, and electrical characteristics. The "KE" suffix denotes a specific manufacturing lot or test grade but does not alter specifications. Verified application circuits-including Sample Circuit 1 (8W amplifier) and Sample Circuit 2 (car audio)-explicitly list 2SD612K and 2SD612 interchangeably, confirming full compatibility in legacy designs.

What is the typical DC current gain (h_FE) range of the 2SD612KE at operating conditions?

The 2SD612KE exhibits h_FE = 20–100 when measured at V_CE = 2V and I_C = −500mA, per the "Electrical Characteristics" table in datasheet No.341. This range corresponds to SANYO's D/E/F rank bins-D (20–40), E (40–70), F (70–100). The device is not gain-binned by default; ordering the "K" variant (e.g., 2SD612K) guarantees selection within a tighter h_FE window for matched-pair applications.

How does the thermal performance of the 2SD612KE compare between case and ambient mounting?

The 2SD612KE delivers 1W power dissipation at T_c = 25°C (case temperature), but only 0.4W at T_a = 25°C (ambient) with no heatsink-demonstrating strong dependence on thermal path. With a 100×100×1.5mm aluminum heatsink and mica insulator, P_C rises to ~0.8W at T_a = 25°C. These derating curves are plotted in Fig. ITR08302/ITR08303 of the datasheet, confirming that effective heatsinking is mandatory for sustained >0.5W operation in enclosed environments.