onsemi 2SB1143S

Overview

2SB1143S from onsemi is a PNP bipolar junction transistor in TO-126ML package, rated for −50 V V_CEO, −4 A I_C, and 1.5 W P_C at T_c = 25°C, with low V_CE(sat) of −350 mV (typ) at I_C = −2 A / I_B = −100 mA. It serves as a high-current switching element in relay drivers and voltage regulators.

For engineers reviewing the 2SB1143S datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed h_FE rank S (140–280), TO-126ML thermal performance, −60 V V_CBO rating, and validated switching times (t_on = 70 ns, t_f = 30 ns) under defined test conditions.

Technical Context

This PNP transistor uses FBET and MBIT processes to achieve low saturation voltage and wide safe operating area (ASO). Its h_FE is specified across two test points: 100–560 at I_C = −100 mA and ≥40 at I_C = −3 A, supporting both small-signal biasing and high-current switching.

It operates within a junction temperature range of −55°C to +150°C and delivers f_T = 150 MHz at V_CE = −10 V, I_C = −50 mA. The device exhibits C_ob = 25 pF (typ) at V_CB = −10 V, f = 1 MHz, enabling predictable high-frequency turn-off behavior.

Key Specifications

Pinout & Package

Package: TO-126ML (JEITA/ JEDEC-compliant TO-126 variant with modified leadframe for improved thermal resistance and mechanical robustness).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP power switching applications.

Compared with 2SB1143S, 2SB1218S offers enhanced voltage margin at the cost of gain predictability, while MJD2955T4 trades package compatibility for superior thermal scalability and SMT manufacturability-neither is pin-compatible, and both require validation of base drive network and PCB layout.

Availability

2SB1143S is available at Aetrix Electronics and suitable for voltage regulators, relay drivers, and lamp drivers requiring stable component supply, long-term industrial lifecycle support, and consistent h_FE binning.

Supply support for 2SB1143S 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, and cloud power applications.

The 2SB1143S belongs to onsemi's general-purpose bipolar power transistor family, engineered for high-current linear and switching applications where low saturation voltage, wide ASO, and reliable thermal performance are critical.

FAQ

What is the guaranteed h_FE range for 2SB1143S?

The 2SB1143S is binned to Rank S, guaranteeing h_FE between 140 and 280 when measured at V_CE = −2 V and I_C = −100 mA. This specification is verified per unit during final test and marked on the device body as "B1143" with rank code "S". The 2SB1143S does not guarantee h_FE at higher currents-designers must verify gain at I_C = −3 A separately using the minimum value of 40.

Can 2SB1143S be used in parallel for higher current handling?

No-2SB1143S is not characterized or recommended for paralleling due to lack of built-in emitter ballasting or matched V_BE(sat) tracking. Its h_FE variation across units and thermal runaway risk under unequal current sharing make forced current sharing impractical. For >4 A applications, use a single higher-rated device such as 2SB1218S or redesign with active current balancing.

What is the maximum allowable case temperature for continuous 2SB1143S operation?

The 2SB1143S supports continuous operation up to T_c = 25°C at its full 10 W P_C rating. Derating begins above 25°C at 80 mW/°C, reaching zero dissipation at T_c = 150°C. For ambient-limited designs, the junction-to-case thermal resistance (R_θJC) is not published, but the TO-126ML package achieves ~1.5°C/W in typical heatsink configurations-always validate with actual board-level thermal testing.

Does 2SB1143S meet RoHS and Pb-free requirements?

Yes-the 2SB1143S is explicitly marked "Pb Free" in the ordering information and complies with RoHS Directive 2011/65/EU. Lead-free soldering profiles must follow J-STD-020 revision D for TO-126ML packages, with peak reflow temperature ≤260°C and time above liquidus ≤60 seconds. The device is not intended for leaded solder processes.

How does the 2SB1143S switching performance compare to 2SB1143T?

The 2SB1143S and 2SB1143T share identical electrical specifications and package; only their h_FE bins differ-S (140–280) vs. T (200–400). Switching parameters (t_on, t_f, t_stg) are unchanged between ranks because they depend on minority carrier lifetime and geometry, not gain. Thus, 2SB1143S delivers identical 70 ns t_on and 30 ns t_f as 2SB1143T under identical bias and load conditions.