onsemi 2SA1209S

Overview

2SA1209S from SANYO Semiconductor is a PNP epitaxial planar silicon transistor designed for high-voltage switching and audio-frequency 100W predriver applications. It features a collector-to-emitter voltage rating of −160 V, collector current capability of −140 mA, DC current gain (h_FE) ranging from 100 to 400 at −5 V and −10 mA, 150 MHz gain-bandwidth product, and low output capacitance of 3.0 pF at −10 V.

For engineers reviewing the 2SA1209S datasheet, pinout, applications, or equivalent options, key selection criteria include its high breakdown voltage (V_CBO = −180 V), fast switching performance (t_on = 0.1 µs, t_f = 0.1 µs), low saturation voltage (V_CE(sat) = −0.14 V typical at −50 mA/−5 mA), and TO-126 package compatibility with thermal dissipation up to 10 W at T_c = 25°C.

Technical Context

The 2SA1209S employs FBET (Flat Base Epitaxial Transistor) process technology to achieve high breakdown voltage and good h_FE linearity. Its low Cob (3.0 pF) and high f_T (150 MHz) support stable high-frequency amplification and fast switching in linear and switching modes.

Designed as a complementary pair with the NPN 2SC2911, it operates in common-emitter configuration with specified test conditions including V_CE = −5 V and I_C = −10 mA for h_FE, and V_CE = −10 V, I_C = −10 mA for f_T. Saturation behavior is characterized at I_C/I_B = 10, confirming suitability for driver-stage biasing and switching control.

Key Specifications

Pinout & Package

2SA1209S is housed in a TO-126 plastic package with exposed collector tab for thermal conduction and mechanical mounting. The case is electrically connected to the collector terminal.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-voltage switching applications.

Compared with 2SA1209S, the 2SA1302 offers identical voltage/current ratings and package but trades bandwidth for ruggedness, while the MJD2955G shifts application focus toward high-current, low-voltage power switching-requiring full circuit reassessment due to mismatched V_CEO, h_FE, and thermal interface.

Availability

2SA1209S is available at Aetrix Electronics and suitable for audio power amplifier predriver, high-voltage switching regulator, and industrial relay driver applications requiring stable component supply and long-term obsolescence management.

Supply support for 2SA1209S 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 Semiconductor Co., Ltd. was a Japanese semiconductor manufacturer specializing in analog, power, and discrete devices before its acquisition by ON Semiconductor in 2011. Known for high-reliability bipolar transistors and power ICs.

The 2SA1209S belongs to SANYO's high-voltage PNP transistor family engineered for audio-frequency predriver and switching applications where breakdown voltage, gain linearity, and thermal robustness are critical.

FAQ

What is the maximum collector-emitter voltage rating for the 2SA1209S?

The 2SA1209S has a maximum collector-to-emitter voltage (V_CEO) rating of −160 V at T_a = 25°C. This rating applies under continuous DC operation with proper heatsinking. Exceeding this voltage-even momentarily-may cause irreversible breakdown. Derating is required above 25°C ambient per the PC–Ta curve in the datasheet.

Does the 2SA1209S have a documented pinout compatible with standard TO-126 footprints?

Yes, the 2SA1209S uses the industry-standard TO-126 package with pin 1 = Emitter, pin 2 = Collector (tab-connected), pin 3 = Base. This matches JEDEC TO-126 outline and is mechanically and electrically compatible with other TO-126 PNP transistors like the 2SA1013 and 2SA1186, though electrical parameters differ.

Can the 2SA1209S be used as a direct replacement for the 2SA1209 without suffix?

Yes-the "S" suffix in 2SA1209S denotes SANYO's internal tape-and-reel packaging variant and does not indicate electrical or mechanical differentiation from the base 2SA1209. Both share identical absolute maximum ratings, electrical characteristics, package dimensions, and pinout per datasheet No. 0779.

What is the typical DC current gain (hFE) of the 2SA1209S at −10 mA collector current?

At V_CE = −5 V and I_C = −10 mA, the 2SA1209S exhibits a typical h_FE of 250, with a guaranteed minimum of 100 and maximum of 400 depending on rank (R/S/T). This wide gain spread is intentional for binning and allows designers to select units matching specific bias stability requirements in the 2SA1209S circuit.

Is the 2SA1209S suitable for automotive-grade applications?

No-the 2SA1209S is specified for standard applications only (e.g., home audio, industrial controls, office equipment). SANYO explicitly excludes medical, aerospace, nuclear, safety-critical transportation, and automotive systems from its intended use scope. It lacks AEC-Q101 qualification, extended temperature screening, or failure-in-time (FIT) data required for automotive deployment.