onsemi 2SB1166S

Overview

2SB1166S from SANYO is a PNP epitaxial planar silicon power transistor rated for 50 V V_CBO, 8 A I_C, and 1.2 W P_C at T_c = 25 °C, designed for high-speed switching in relay drivers and DC-DC converters.

For engineers reviewing the 2SB1166S datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed h_FE range (140–400), low V_CE(sat) ≤ 400 mV at I_C = −4 A / I_B = −200 mA, f_T ≥ 180 MHz, and TO-126LP package thermal performance.

Technical Context

The 2SB1166S operates as a medium-power PNP bipolar junction transistor with fixed-emitter configuration, optimized for linear amplification and saturated switching. Its h_FE is binned per specification sheet into four groups (140–170, 170–200, 200–240, 240–400) at V_CE = −2 V and I_C = −0.5 A.

Switching behavior is characterized by t_ON = 50 ns, t_OFF = 500 ns, and t_f = 20 ns under defined test conditions (V_CC = −25 V, R_L = 50 Ω, I_B1/I_B2 ratio set for fast turn-on/turn-off). V_BE(sat) remains ≤ −1.2 V at I_C = −4 A / I_B = −200 mA.

Key Specifications

Pinout & Package

SANYO specifies the 2SB1166S in the TO-126LP plastic package (JEDEC TO-126 variant with lead pitch and footprint matching standard TO-126), featuring a metal tab electrically connected to the collector for direct heatsink mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2SB1218 and MJD2955G, the 2SB1166S delivers superior combination of high current (−8 A), tight h_FE binning (140–400), and high f_T (≥180 MHz), making it optimal for precision-switching designs where gain predictability and speed are critical.

Availability

2SB1166S is available at Aetrix Electronics and suitable for relay drivers, DC-DC converters, inverter half-bridge legs, and high-voltage linear amplifiers requiring stable component supply and long-term obsolescence management.

Supply support for 2SB1166S 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, power, and optoelectronic components before its acquisition by Panasonic in 2011; known for high-reliability discrete transistors and ICs.

The 2SB1166S belongs to SANYO's legacy PNP/NPN epitaxial planar transistor family engineered for industrial-grade switching and amplification, emphasizing thermal stability, parameter consistency, and ruggedized packaging.

FAQ

What is the maximum continuous collector current rating for the 2SB1166S?

The 2SB1166S has a maximum continuous collector current rating of −8 A at case temperature T_c = 25 °C. This rating assumes proper heatsinking; derating is required above 25 °C case temperature per the PC–Ta curve in the datasheet. At ambient temperature (T_a), the practical continuous current is limited to approximately −1.5 A without heatsink and up to −6 A with moderate heatsinking.

Does the 2SB1166S have a built-in base-emitter resistor?

No, the 2SB1166S is a standard three-terminal PNP bipolar transistor with no integrated base-emitter resistor. It requires external base biasing circuitry-typically a series base resistor-to control collector current and ensure saturation. The absence of internal resistors gives designers full flexibility in setting operating points and switching dynamics.

What is the guaranteed h_FE range for the 2SB1166S, and how is it binned?

The 2SB1166S is binned into four h_FE groups: Q (140–170), R (170–200), S (200–240), and T (240–400), measured at V_CE = −2 V and I_C = −0.5 A. Each unit is marked with its bin code (Q/R/S/T) on the package. This binning enables precise base drive design without over-sizing drive circuits or risking incomplete saturation.

Can the 2SB1166S be used in parallel configurations for higher current handling?

Parallel operation of 2SB1166S devices is not recommended without individual emitter resistors and matched h_FE bins due to thermal runaway risk. The device lacks built-in emitter ballasting, and parameter spread-even within same bin-can cause current imbalance. For >8 A applications, use a single higher-rated device or a dedicated power module instead.

What is the thermal resistance from junction to case (R_θJC) for the 2SB1166S?

The 2SB1166S has a typical junction-to-case thermal resistance (R_θJC) of 12.5 °C/W, derived from its 1.2 W power dissipation rating at T_c = 25 °C and maximum junction temperature T_j = 150 °C. This value assumes full metal tab contact with a heatsink; poor thermal interface increases effective R_θJC and reduces safe operating current.