Diodes Incorporated MMBT123S-7-F

Overview

MMBT123S-7-F from Diodes Incorporated is a 1 A NPN bipolar junction transistor in SOT-23 package, rated for V_CEO = 18 V and P_D = 300 mW, with h_FE = 150–800 at I_C = 100 mA and V_CE = 1 V, used for medium-power switching in DC-DC converter control stages and load driver circuits.

For engineers reviewing the MMBT123S-7-F datasheet, MMBT123S-7-F pinout, MMBT123S-7-F application, or MMBT123S-7-F equivalent, key selection criteria include verified V_CEO/I_C derating behavior, h_FE consistency across production lots, SOT-23 thermal resistance (R_θJA = 417 °C/W), and RoHS-compliant matte tin plating on Alloy 42 leadframe.

Technical Context

This NPN transistor uses epitaxial planar die construction to ensure stable gain and low leakage. It operates reliably from –55 °C to +150 °C and supports continuous collector current up to 1 A with V_CE(SAT) ≤ 0.5 V at I_C = 300 mA / I_B = 30 mA.

Its f_T = 100 MHz enables use in moderate-speed switching applications, while C_obo = 8 pF at V_CB = 10 V supports predictable turn-off timing in PWM-driven loads.

Key Specifications

Pinout & Package

Package: SOT-23 - Surface-mount plastic package (UL 94V-0), 0.008 g weight, moisture sensitivity level 1, lead-free matte tin plating over Alloy 42 leadframe.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN switching transistor applications.

Compared with MMBT2222A-7-F and PN2222A, the MMBT123S-7-F delivers higher continuous current (1 A vs. 600 mA/600 mA) in an SMT-optimized SOT-23 package, making it preferable for space-constrained, high-current digital switching where thermal performance and manufacturability are prioritized.

Availability

MMBT123S-7-F is available at Aetrix Electronics and suitable for DC-DC converter switching, LED load driving, relay interfacing, and microcontroller I/O expansion requiring stable component supply and consistent parametric performance across production batches.

Supply support for MMBT123S-7-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, serving industrial, computing, consumer, and communications markets with high-reliability components.

The MMBT123S belongs to Diodes' general-purpose bipolar transistor product line, designed specifically for cost-sensitive, medium-power switching and amplification applications in automotive, industrial control, and power management systems.

FAQ

What is the maximum allowable collector current for continuous operation?

The MMBT123S-7-F is rated for 1 A continuous collector current at T_A = 25 °C. Derating is required above 25 °C per the curve in Figure 1 of the datasheet: power dissipation drops linearly to zero at 150 °C ambient, corresponding to ~600 mA at 100 °C ambient on standard FR-4 PCB.

Is this transistor suitable for direct GPIO drive from a 3.3 V microcontroller?

Yes - with I_C ≤ 100 mA, a 3.3 V GPIO can drive the base through a 1–2.2 kΩ resistor to achieve I_B ≈ 1–1.5 mA, delivering h_FE-supported I_C well within spec. For I_C > 300 mA, external base buffering is recommended to ensure full saturation and minimize V_CE(SAT).

Does the "-7-F" suffix indicate tape-and-reel packaging?

Yes - the "-7-F" suffix denotes SOT-23 packaging in 3000-unit tape-and-reel format per Diodes Incorporated's ordering information. The "F" confirms RoHS-compliant, halogen-free green packaging; "7" identifies the SOT-23 carrier tape configuration per AP02007 specification.

How does its thermal performance compare to larger packages like SOT-223?

The MMBT123S-7-F has R_θJA = 417 °C/W on FR-4, significantly higher than SOT-223 devices (~200 °C/W). This means it dissipates less power before reaching thermal limits. For >300 mW steady-state loads, SOT-223 or DPAK alternatives are preferred; the SOT-23 version is optimized for pulsed or intermittent operation with tight board space constraints.