### LD1085D2M50-R Overview The **LD1085D2M50-R** is a low-drop voltage regulator capable of providing up to **3A** of output current. It is part of the LD1085 series by STMicroelectronics, designed specifically to provide high efficiency for fixed-voltage applications. --- ### Technical Specifications | Parameter | Specification | | :--- | :--- | | **Regulator Type** | Fixed Linear Voltage Regulator (LDO) | | **Output Voltage** | 5.0 V | | **Maximum Output Current** | 3.0 A | | **Dropout Voltage (Typical)** | 1.3 V @ 3A | | **Input Voltage (Max)** | 30 V | | **Package / Case** | D2PAK (TO-263) | | **Operating Temperature** | -40°C to +125°C | --- ### Key Electronic Features 1. **Low Dropout (LDO):** Unlike standard regulators (like the 7805), which require ~2-3V overhead, the LD1085 only requires about 1.3V above the output voltage to function at full load. 2. **Internal Protection:** * **Current Limiting:** Protects the device against output short circuits. * **Thermal Shutdown:** Automatically turns off if the internal junction temperature exceeds safety limits (usually around 150°C). 3. **High Current Capability:** Providing 3A makes it suitable for power-hungry components like microcontrollers with multiple peripherals, high-speed logic, or small motors. --- ### Pin Configuration (D2PAK) The device typically follows the standard pinout for D2PAK regulators: | Pin Number | Name | Function | | :--- | :--- | :--- | | **1** | **GND** | Ground connection. | | **2 / Tab** | **Vout** | Regulated 5V output. The metal tab is also Vout. | | **3** | **Vin** | Unregulated input voltage. | --- ### Typical Application Circuit To ensure stability and reduce noise, external capacitors are required. The LD1085 series requires an output capacitor for stability. ```text Input (Vin) ----[ LD1085 ]---- Output (Vout: 5V) | | Cin (10uF) [ ] [ ] Cout (10uF - 22uF Tantalum) | | GND ------------+----+---------------- GND ``` * **Cin:** A 10µF capacitor is recommended if the regulator is far from the power supply filter. * **Cout:** A minimum of 10µF (typically Tantalum) is required for stability. The ESR (Equivalent Series Resistance) of this capacitor is critical for preventing oscillation. ---