### 2SB1140-R: Overview and Specifications The **2SB1140-R** is a Silicon PNP Epitaxial Planar Transistor designed primarily for low-frequency power amplification and high-current switching applications. It is known for its high current capacity and low saturation voltage. --- ### 1. Key Technical Specifications Below are the absolute maximum ratings and electrical characteristics typically found in the datasheet: | Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | **Collector-Base Voltage** | $V_{CBO}$ | -60 | V | | **Collector-Emitter Voltage** | $V_{CEO}$ | -50 | V | | **Emitter-Base Voltage** | $V_{EBO}$ | -6 | V | | **Collector Current (DC)** | $I_C$ | -2 | A | | **Collector Current (Pulse)** | $I_{CP}$ | -4 | A | | **Collector Power Dissipation** | $P_C$ | 1.0 (at $T_a=25^\circ C$) | W | | **Junction Temperature** | $T_j$ | 150 | $^\circ$C | --- ### 2. The "R" Classification The suffix **"R"** in 2SB1140-R refers to the **hFE (DC Current Gain)** rank. Manufacturers categorize these transistors into grades based on their gain levels: | Rank | R | S | T | U | | :--- | :--- | :--- | :--- | :--- | | **hFE Range** | 100 to 200 | 140 to 280 | 200 to 400 | 280 to 560 | *Note: The "R" rank indicates a gain between 100 and 200.* --- ### 3. Key Features * **High Current Capacity:** Can handle up to 2 Amps continuous, which is high for its compact package size. * **Low Saturation Voltage:** $V_{CE(sat)}$ is typically low (around -0.3V at $I_C = -1A$), meaning it generates less heat during switching and is highly efficient. * **Fast Switching:** Suitable for high-speed switching applications. * **Complementary Pair:** It is often paired with the **2SD1680** (NPN version) for push-pull amplifier circuits. --- ### 4. Common Applications 1. **Voltage Regulators:** Used in power supply circuits to maintain steady voltage. 2. **Relay/Solenoid Drivers:** Due to its high current handling, it can easily drive mechanical components. 3. **Audio Amplifiers:** Used in the output stages of low-to-medium power audio systems. 4. **DC-DC Converters:** Employed in switching regulators for power conversion. --- ### 5. Physical Package The 2SB1140 is typically housed in a **TO-126** (also known as SOT-32) or a similar through-hole package, which allows for easy mounting to a heat sink if required. **Pinout Configuration:** 1. **Emitter** 2. **Collector** 3. **Base**