The **2SB772A-R** is a medium-power PNP epitaxial silicon transistor. It is widely used in power switching applications and voltage regulation due to its high current capacity and low saturation voltage. ### 1. Key Technical Specifications The "A" suffix usually denotes a higher voltage rating than the standard 2SB772, and the "R" suffix indicates the specific **hFE (DC Current Gain)** classification. | Parameter | Symbol | Maximum Rating | | :--- | :--- | :--- | | Collector-Base Voltage | $V_{CBO}$ | -40 V | | Collector-Emitter Voltage | $V_{CEO}$ | -30 V | | Emitter-Base Voltage | $V_{EBO}$ | -5 V | | Collector Current (DC) | $I_C$ | -3 A | | Collector Current (Pulse) | $I_{CP}$ | -7 A | | Total Power Dissipation ($T_a = 25^\circ C$) | $P_D$ | 1.25 W | | Junction Temperature | $T_j$ | 150 °C | --- ### 2. Gain Classification (R Rank) The "R" suffix refers to the hFE (DC current gain) range. Transistors are sorted into bins to ensure circuit stability: * **R Rank Range:** 100 to 200 hFE * **Q Rank Range:** 160 to 320 hFE * **P Rank Range:** 200 to 400 hFE --- ### 3. Pin Configuration and Package The 2SB772A-R is most commonly found in the **TO-126** package (also known as SOT-32). This package is designed to be easily mounted to a heatsink. | Pin Number | Assignment | | :--- | :--- | | 1 | **Emitter (E)** | | 2 | **Collector (C)** | | 3 | **Base (B)** | --- ### 4. Typical Applications * **Voltage Regulation:** Used in linear regulators to manage power output. * **Relay Drivers:** High collector current allows it to drive mechanical relays or small DC motors. * **Audio Amplifiers:** Frequently used in the output stage of low-to-medium power audio amplifiers. * **DC-DC Converters:** Suitable for switching circuits due to its low saturation voltage ($V_{CE(sat)}$). ### 5. Complementary Part The NPN complement to the 2SB772A is the **2SD882A**. These are often used together in "Push-Pull" amplifier configurations. ---