The **LR9280CL-40-AE3-R** is a specific low-dropout (LDO) linear regulator typically manufactured by UTC (Unisonic Technologies Co.). It is designed to provide a stable, fixed output voltage from a fluctuating input voltage. --- ### 1. Part Number Breakdown Understanding the suffix codes helps identify the specific characteristics of this component: | Code Segment | Meaning | | :--- | :--- | | **LR9280** | Series identification (High-speed LDO) | | **CL** | Accuracy and specific internal configuration | | **40** | Output Voltage (4.0V) | | **AE3** | Package Type (Typically SOT-23) | | **R** | Packing style (Tape and Reel) | --- ### 2. Key Technical Specifications The LR9280 series is known for high ripple rejection and low noise, making it suitable for RF and sensitive analog circuits. * **Output Voltage:** Fixed 4.0V. * **Maximum Input Voltage:** Usually up to 6V or 7V (varies by sub-series). * **Maximum Output Current:** Typically 300mA to 500mA. * **Dropout Voltage:** Low dropout (usually $<300\text{mV}$ at full load). * **Quiescent Current:** Very low, often around $50\mu\text{A}$, extending battery life. * **PSRR (Power Supply Rejection Ratio):** High (often $>70\text{dB}$ at $1\text{kHz}$), which filters out input noise. --- ### 3. Pin Configuration (SOT-23) The standard AE3 (SOT-23) package usually follows this pinout: | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **GND** | Ground connection | | 2 | **VOUT** | Regulated output voltage (4.0V) | | 3 | **VIN** | Unregulated input voltage | --- ### 4. Typical Application Circuit To ensure stability, LDOs require external capacitors. ```c Input (VIN) ----[ C1: 1uF ]----| LR9280 |----[ C2: 1uF ]---- Output (4.0V) | GND | | Ground ``` * **C1 (Input Capacitor):** Stabilizes the input and minimizes noise. * **C2 (Output Capacitor):** Crucial for loop stability and transient response. Ceramic capacitors are typically recommended. --- ### 5. Common Use Cases * **Mobile Devices:** Powering sensors or Bluetooth modules. * **Battery-Powered Systems:** Due to low quiescent current. * **RF Modules:** Where low noise and high PSRR are required to prevent signal interference. ---