onsemi 2SB1131S

Overview

2SB1131S from SANYO is a PNP epitaxial planar silicon transistor designed for high-current switching in strobe circuits, lamp drivers, and relay drivers. It supports −5 A collector current, −20 V collector–emitter voltage, 1 W power dissipation, −1.0 V typical V_BE(sat) at −3 A/−60 mA, and features fast switching with t_on = 40 ns and t_off = 200 ns.

For engineers reviewing the 2SB1131S datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP switching capability, low saturation voltage under high I_C, thermal derating behavior above 25°C, and compatibility with TTL/CMOS drive levels in pulse-driven loads.

Technical Context

The 2SB1131S operates as a medium-power PNP bipolar junction transistor optimized for pulsed high-current loads. Its FBET/MBIT process enables low V_CE(sat) (−250 mV min) at I_C = −3 A and I_B = −60 mA, and f_T = 30 MHz at V_CE = −5 V, I_C = −200 mA - confirming suitability for strobe flash timing and DC-DC converter switch control.

It exhibits defined absolute maximum ratings: T_j = +150°C, T_stg = −55°C to +150°C, and V_CEO = −20 V. Electrical characteristics are specified at T_a = 25°C with strict derating curves for P_C vs. T_a, requiring heatsinking above ~50°C ambient in continuous operation.

Key Specifications

Pinout & Package

2SB1131S is housed in a TO-126 plastic package (SANYO MP designation), with standard lead configuration: Emitter (Pin 1), Collector (Pin 2), Base (Pin 3). 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-current switching applications.

Compared with 2SB1131S, the 2SB1218 trades speed for voltage margin while the MJD2955 trades package size and bandwidth for current capacity - making 2SB1131S the optimal balance for space-constrained, fast-switching strobe and lamp driver designs.

Availability

2SB1131S is available at Aetrix Electronics and suitable for strobe flash circuits, relay driver stages, and lamp driver modules requiring stable component supply, long-term obsolescence planning, and traceable sourcing for industrial and consumer electronics manufacturing.

Supply support for 2SB1131S 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 known for high-reliability discrete devices and analog ICs before its acquisition by Panasonic in 2012; its transistor product lines remain widely used in industrial and automotive applications.

The 2SB1131S belongs to SANYO's MP-series medium-power PNP transistor family, engineered specifically for high-current, fast-switching applications including photographic strobes, solid-state relays, and DC load control where low saturation voltage and thermal stability are critical.

FAQ

What is the maximum continuous collector current rating for the 2SB1131S?

The 2SB1131S has a maximum continuous collector current (I_C) rating of −5 A at T_a = 25°C with proper heatsinking. Derating is required above 25°C ambient per the published P_C vs. T_a curve; at 70°C ambient, usable I_C drops to approximately −3.5 A to maintain junction temperature below +150°C. Always verify thermal design using the 2SB1131S θ_JA value in your specific PCB layout.

Does the 2SB1131S support TTL-level base drive?

Yes, the 2SB1131S supports direct TTL-level base drive when used with appropriate current-limiting resistors. With h_FE ≥ 100 at I_C = −500 mA, a 1 kΩ base resistor from a 5 V TTL output delivers ~4.3 mA I_B, sufficient to saturate the 2SB1131S up to ~430 mA I_C. For full −5 A operation, external amplification or lower-resistance drive (e.g., 100 Ω) is required to achieve I_B ≥ −100 mA.

What is the typical V_BE(sat) of the 2SB1131S and how does it affect base drive design?

The typical V_BE(sat) of the 2SB1131S is −1.0 V at I_C = −3 A and I_B = −60 mA. This relatively high base–emitter saturation voltage means base drive circuits must supply adequate forward voltage - especially critical when using 3.3 V logic. A Darlington or MOSFET pre-driver may be needed for full saturation at low supply voltages. The 2SB1131S datasheet provides V_BE(sat) vs. I_C curves to guide resistor selection.

Can the 2SB1131S be used in avalanche mode for energy recovery?

No, the 2SB1131S is not rated or characterized for controlled avalanche operation. Its absolute maximum V_CEO of −20 V is a hard breakdown limit, and operation beyond this risks irreversible damage. For inductive load switching, always use an external flyback diode (e.g., 1N4007) across the load - the 2SB1131S itself provides no built-in protection or energy recovery capability.

Is the 2SB1131S RoHS compliant and what is its lead finish?

The 2SB1131S was originally manufactured prior to RoHS enforcement (pre-2006) and carries a leaded (SnPb) termination finish. It is not RoHS compliant in its original SANYO production form. For RoHS-compliant alternatives, consider modern equivalents such as the NSS12201CF8T1G (ON Semiconductor) or ZTX951 (Diodes Inc.), which match key parameters while meeting Pb-free requirements.