The **LR9103L-28-AF5-R** is a low-dropout (LDO) linear voltage regulator manufactured by UTC (Unisonic Technologies Co., Ltd.). It is designed for battery-powered applications requiring low power consumption and stability. --- ### 1. Technical Specifications The part number itself reveals specific characteristics about its performance and packaging: | Parameter | Specification | | :--- | :--- | | **Fixed Output Voltage** | 2.8V | | **Input Voltage Range** | Up to 7V | | **Max Output Current** | 300mA | | **Quiescent Current** | Typ. 70µA | | **Dropout Voltage** | ~210mV @ 100mA | | **Package Type** | SOT-25 (AF5) | | **Operating Temperature** | -40°C to +85°C | --- ### 2. Part Number Breakdown The naming convention follows UTC’s standard identification system: * **LR9103L**: Series name (Low-power CMOS LDO). * **28**: Output voltage code (2.8 Volts). * **AF5**: Package code for SOT-25. * **R**: Tape and Reel packaging. --- ### 3. Key Features and Applications The LR9103L series is characterized by high accuracy and low noise, making it suitable for sensitive electronic circuits. #### Features * **High Ripple Rejection:** Provides clean power for RF and analog circuits. * **Low Dropout:** Allows the device to operate even when the input voltage is very close to the output voltage. * **Built-in Protections:** Includes thermal shutdown and current limiting to prevent damage during a short circuit. * **Enable Pin:** Allows the regulator to be turned off via a logic signal to save power (Standby mode). #### Typical Applications * Mobile phones and handheld devices. * Digital cameras and camcorders. * Battery-powered medical equipment. * Reference voltage sources for microcontrollers. --- ### 4. Typical Application Circuit To ensure stability, LDOs usually require external capacitors. ```c // Standard wiring for LR9103L [VIN] ----[ CIN: 1uF ]---- (Pin 1: VIN) (Pin 2: GND) ---- [GND] [ON/OFF] ----------------- (Pin 3: EN) (Pin 4: NC/BP) [VOUT] ----[ COUT: 1uF ]--- (Pin 5: VOUT) ``` ---