The **LD1117DTC-R** is a popular low-dropout (LDO) linear voltage regulator. It is part of the LD1117 series, known for providing a stable output voltage even when the input voltage is only slightly higher than the output. --- ### ## Technical Specifications Below is a summary of the core electrical characteristics for the LD1117DTC-R: | Parameter | Specification | | :--- | :--- | | **Output Type** | Fixed | | **Output Voltage** | 1.2V (Note: The "DTC" suffix typically denotes 1.2V in this family) | | **Max Output Current** | 800 mA | | **Max Input Voltage** | 15 V | | **Dropout Voltage** | 1.0V to 1.2V (typ. at 800mA) | | **Package Type** | TO-252 (DPAK) | | **Operating Temperature** | -40°C to 125°C | --- ### ## Key Features 1. **Low Dropout:** Unlike standard regulators (like the 7805), it requires much less "headroom" between input and output. 2. **Internal Protection:** It includes internal current limiting and thermal shutdown protection to prevent damage during a short circuit or overheating. 3. **High Efficiency (Relative):** Within linear regulator standards, it is efficient for low-power applications, though it dissipates excess voltage as heat. 4. **Surface Mount Design:** The DPAK (TO-252) package is designed for automated surface mount assembly and provides good heat dissipation through the PCB copper. --- ### ## Pin Configuration In the TO-252 (DPAK) package, the pinout is generally as follows: 1. **GND/ADJ:** Ground for fixed versions; Reference pin for adjustable versions. 2. **Vout (and Tab):** The regulated output voltage. 3. **Vin:** The unregulated input voltage. --- ### ## Application Circuit To ensure stability, LDOs require specific capacitors. For the LD1117 series, a tantalum or electrolytic capacitor on the output is crucial for frequency compensation. ```markdown Vin ----[ C1: 10uF ]----( LD1117 )----[ C2: 10uF ]---- Vout | | | GND GND GND ``` * **C1 (Input Capacitor):** Required if the regulator is far from the power supply filter. * **C2 (Output Capacitor):** Mandatory. Usually 10µF or higher to ensure stability and improve transient response. ---