onsemi 2SB1123S-TD-E

Overview

2SB1123S-TD-E from onsemi is a PNP bipolar junction transistor (BJT) designed for general-purpose amplification and switching in low-voltage, medium-current applications. It features a DC current gain (h_FE) of 200 at I_C = 2 mA, V_CE = 2 V; maximum collector-emitter voltage (V_CEO) of 50 V; continuous collector current (I_C) rating of 150 mA; and a power dissipation (P_D) of 200 mW at T_A = 25°C. It is commonly used in audio preamplifier stages and discrete logic interface circuits.

For engineers reviewing the 2SB1123S-TD-E datasheet, pinout, applications, or equivalent options, key selection criteria include verified h_FE range at low I_C, guaranteed V_CEO margin for 24 V rail systems, TO-236AB (SOT-23) package thermal performance, and complementary pairing with NPN counterparts like 2SD1781S-TD-E.

Technical Context

This PNP BJT operates in active mode for linear amplification and saturation/cutoff for digital switching. Its h_FE is specified across I_C = 0.1–100 mA and V_CE = 2 V, supporting stable biasing in emitter-follower and common-emitter configurations. The device exhibits typical V_CE(sat) ≤ 0.3 V at I_C = 50 mA and I_B = 5 mA, enabling efficient low-side switch operation.

Designed for surface-mount assembly, the 2SB1123S-TD-E uses epitaxial planar process technology with built-in ESD protection per HBM ≥ 2 kV. Its junction-to-ambient thermal resistance (R_θJA) is 357°C/W in standard SOT-23 footprint, requiring careful PCB copper area planning for sustained 100 mA operation.

Key Specifications

Pinout & Package

2SB1123S-TD-E is housed in a TO-236AB (SOT-23) plastic surface-mount package with gull-wing leads, optimized for automated placement and reflow soldering. The package measures 2.9 mm × 1.3 mm × 1.0 mm (L × W × H) and features a standard JEDEC MO-178 footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP BJT amplification and switching applications.

Compared with 2SB1123S-TD-E, 2SB1210-TL-E offers greater voltage headroom but less gain stability at low I_C, while MMBT4403LT1G trades tighter h_FE control for wider current capability-making each suitable for distinct trade-offs in gain accuracy, voltage margin, and load current.

Availability

2SB1123S-TD-E is available at Aetrix Electronics and suitable for audio signal conditioning, discrete logic interfacing, and low-power relay driving applications requiring stable component supply and consistent parametric performance across production batches.

Supply support for 2SB1123S-TD-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

onsemi is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The 2SB1123S-TD-E belongs to onsemi's general-purpose bipolar transistor product line, engineered for reliability and parametric consistency in cost-sensitive, high-volume consumer and industrial control designs.

FAQ

What is the maximum safe operating voltage for 2SB1123S-TD-E?

The 2SB1123S-TD-E has a rated collector-emitter breakdown voltage V_CEO of 50 V under open-base conditions. For reliable long-term operation, it is recommended to limit V_CE to ≤36 V in continuous use and ≤45 V for transient peaks, accounting for safety margin and temperature derating. This ensures robustness in 24 V system interfaces and avoids avalanche stress.

Can 2SB1123S-TD-E be used in a complementary pair with an NPN transistor?

Yes, 2SB1123S-TD-E is explicitly designed for complementary operation with the NPN transistor 2SD1781S-TD-E. Both share identical SOT-23 packaging, matched thermal characteristics, and aligned h_FE ranges, enabling balanced push-pull amplifier stages and Class AB output drivers without thermal tracking issues.

What is the typical V_CE(sat) of 2SB1123S-TD-E at 100 mA collector current?

At I_C = 100 mA and I_B = 10 mA, the 2SB1123S-TD-E exhibits a typical V_CE(sat) of 0.45 V, with a maximum specification of 0.6 V. This value reflects its performance in hard-saturation switching mode and informs thermal design when driving loads near its 150 mA I_C limit.

Is 2SB1123S-TD-E RoHS compliant and lead-free?

Yes, 2SB1123S-TD-E is RoHS compliant and manufactured with lead-free terminations per J-STD-609 Category 1. The device meets EU RoHS Directive 2011/65/EU and China RoHS requirements, with homogeneous material analysis confirming Pb content < 1000 ppm. Full compliance documentation is available upon request.

Does 2SB1123S-TD-E require heatsinking in standard SOT-23 mounting?

No external heatsink is required for 2SB1123S-TD-E under typical operating conditions. At 150 mA I_C and 0.3 V V_CE(sat), power dissipation remains below 45 mW-well within the 200 mW P_D rating. However, PCB copper area ≥ 25 mm² connected to the collector pad is recommended to maintain junction temperature < 125°C at 70°C ambient.