## MMBT4401G-AE3-R Overview The **MMBT4401G-AE3-R** is a widely used **NPN General Purpose Transistor** designed for low-power switching and amplification applications. It is the surface-mount (SMD) equivalent of the classic through-hole 2N4401 transistor. --- ### 1. Key Technical Specifications The following table outlines the absolute maximum ratings and electrical characteristics for the MMBT4401G. | Parameter | Symbol | Value | Unit | | :--- | :--- | :--- | :--- | | **Collector-Emitter Voltage** | $V_{CEO}$ | 40 | V | | **Collector-Base Voltage** | $V_{CBO}$ | 60 | V | | **Emitter-Base Voltage** | $V_{EBO}$ | 6.0 | V | | **Continuous Collector Current** | $I_C$ | 600 | mA | | **Total Power Dissipation** | $P_D$ | 225 - 350 | mW | | **DC Current Gain** | $h_{FE}$ | 100 - 300 | @ 150mA | | **Transition Frequency** | $f_T$ | 250 (min) | MHz | --- ### 2. Physical & Packaging Information The part numbering provides specific information about the package and manufacturing standards: * **Package Type:** **SOT-23** (Small Outline Transistor). This is a 3-lead surface mount package. * **"G":** Indicates that the part is **Halogen-Free**. * **"AE3":** Typically refers to the SOT-23 package code in the manufacturer’s (UTC - Unisonic Technologies) nomenclature. * **"R":** Indicates **Tape & Reel** packaging for automated pick-and-place assembly. --- ### 3. Pin Configuration (SOT-23) | Pin Number | Function | Description | | :--- | :--- | :--- | | **1** | **Base** | The trigger that controls the flow between Collector and Emitter. | | **2** | **Emitter** | The lead where the current exits (for NPN). | | **3** | **Collector** | The lead where the current enters. | --- ### 4. Typical Applications The MMBT4401G is highly versatile due to its high collector current ($600mA$) compared to other signal transistors like the MMBT3904 ($200mA$). * **Switching:** Driving LEDs, small relays, or solenoids. * **Amplification:** Audio pre-amplification and signal processing. * **Level Shifting:** Converting logic levels between different voltage rails. * **PWM Control:** Used in moderate-speed pulse width modulation circuits. ---