onsemi 2SB1234-TB-E

Overview

2SB1234-TB-E from SANYO Semiconductor is a PNP epitaxial planar silicon Darlington transistor in a CP (SOT-323) package, rated for V_CEO = −50 V, I_C = −200 mA, P_C = 200 mW, with h_FE ≥ 5000 at I_C = −10 mA and V_CE = −2 V. It serves as a high-gain switching or linear amplification device in low-power driver stages.

For engineers reviewing the 2SB1234-TB-E datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed DC current gain at low/mid-current bias, V_CE(sat) ≤ −1.5 V under I_C = −100 mA / I_B = −100 µA, thermal derating per PC–Ta curve, and CP package compatibility with space-constrained PCB layouts.

Technical Context

The 2SB1234-TB-E implements a monolithic Darlington pair structure to achieve ultra-high h_FE while maintaining single-transistor footprint and bias simplicity. Its V_(BR)CEO = −50 V and V_(BR)CBO = −80 V support operation in moderate-voltage analog and switching rails up to −40 V.

Designed for ambient temperatures from −55°C to +150°C, it features T_j = 150°C maximum junction rating and exhibits predictable h_FE degradation above 75°C, as confirmed by h_FE–I_C curves across −25°C/25°C/75°C. V_BE(sat) ranges from −1.5 V to −2.0 V at I_C = −100 mA, indicating dual-base forward drop inherent to Darlington topology.

Key Specifications

Pinout & Package

The 2SB1234-TB-E is housed in a CP package (JEDEC TO-236AB / SOT-323), measuring 2.5 mm × 1.5 mm × 0.95 mm (L × W × H), with gull-wing leads and tape-and-reel packaging (TB-E designation).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP Darlington transistor applications.

Compared with MMBT2907A and NSV2907AT1G, the 2SB1234-TB-E offers the smallest footprint (CP vs. SOT-23) and highest guaranteed h_FE at low bias, making it optimal for ultra-compact, low-drive designs-though its −50 V V_CEO requires careful rail selection versus the −60 V alternatives.

Availability

2SB1234-TB-E is available at Aetrix Electronics and suitable for LED driver circuits, solenoid control modules, AF amplifier stages, and low-power relay drivers requiring stable component supply and long-term obsolescence management.

Supply support for 2SB1234-TB-E 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 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 automotive-grade components.

The 2SB1234-TB-E belongs to SANYO's legacy CP-packaged Darlington transistor family, designed specifically for space-constrained consumer and industrial driver applications demanding ultra-high DC current gain in minimal footprint.

FAQ

What is the package type and marking code for 2SB1234-TB-E?

The 2SB1234-TB-E uses the CP package (JEDEC TO-236AB / SOT-323), with physical dimensions of 2.5 mm × 1.5 mm × 0.95 mm. Its top-side marking is "PL", as specified in the official SANYO datasheet No.2553. The "TB-E" suffix denotes tape-and-reel packaging with embossed carrier tape, standard for automated SMT placement. This compact footprint makes the 2SB1234-TB-E ideal for high-density PCB layouts where space is at a premium.

Does 2SB1234-TB-E support pulse current operation, and what is its rated I_CP?

Yes, the 2SB1234-TB-E supports pulsed operation with a rated collector current (pulse) I_CP of −400 mA, as defined in the Absolute Maximum Ratings table. This rating applies under specified pulse conditions (duty cycle, pulse width, and ambient temperature), enabling short-duration peak loads such as solenoid inrush or relay coil energization. Engineers must verify thermal limits using the PC–Ta derating curve and ensure pulse duration remains within safe junction temperature rise boundaries for the 2SB1234-TB-E.

What is the guaranteed minimum h_FE for 2SB1234-TB-E, and at what test conditions?

The 2SB1234-TB-E guarantees a minimum DC current gain h_FE of 5000 at V_CE = −2 V and I_C = −10 mA, per the Electrical Characteristics table. A second h_FE bin (h_FE2) specifies ≥3000 (typical 4000) at I_C = −100 mA, confirming usable gain even under higher load conditions. This high, verified gain allows the 2SB1234-TB-E to operate with microamp-level base drive, reducing loading on upstream logic or MCU outputs.

Can 2SB1234-TB-E replace standard PNP transistors like 2N3906 in existing designs?

The 2SB1234-TB-E is not a direct functional replacement for general-purpose PNP transistors like the 2N3906 due to its Darlington architecture, which results in higher V_BE(sat) (−1.5 V to −2.0 V) and slower switching speed. While it shares similar voltage/current ratings, its doubled base-emitter junction drop and internal capacitance affect timing and biasing. Replacing 2N3906 with 2SB1234-TB-E requires circuit revalidation-especially in linear amplifiers or high-speed switches-though it may simplify base drive in low-frequency, high-gain applications.

Is 2SB1234-TB-E suitable for automotive applications?

No, the 2SB1234-TB-E is not qualified for automotive applications. The original SANYO datasheet explicitly states that these products "do not have specifications that can handle applications that require extremely high levels of reliability, such as … aircraft's control systems" and cautions against use in life-support or safety-critical systems. It lacks AEC-Q101 qualification, extended temperature screening, and automotive-specific failure mode analysis. For automotive-grade equivalents, engineers should select AEC-Q101-certified Darlington transistors with documented PPAP and TS 16949 compliance-not the 2SB1234-TB-E.