The **LDK220PU-R** is a high-performance, low-dropout (LDO) linear voltage regulator manufactured by **STMicroelectronics**. It is designed for applications where space is limited and power efficiency (specifically low quiescent current) is critical. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Input Voltage Range** | 2.5 V to 13.2 V | | **Output Voltage** | Fixed (specific to the 'PU' variant) or Adjustable | | **Maximum Output Current** | 200 mA | | **Dropout Voltage** | 100 mV @ 100 mA (typical) | | **Quiescent Current ($I_q$)** | 55 µA (typical) / < 1 µA in Shutdown | | **PSRR (Power Supply Rejection Ratio)** | 60 dB @ 1 kHz | | **Package Type** | DFN6 (2x2 mm) - "PU" Suffix | | **Operating Temperature** | -40°C to +125°C | --- ### 2. Core Features and Functionality * **Low Dropout (LDO):** The device can maintain a stable output voltage even when the input voltage is very close to the output target (only 100-200mV difference required). * **Enable (EN) Pin:** This allows the regulator to be turned on or off via a logic signal. When disabled, it enters a "shutdown mode" consuming almost zero power. * **Stability:** It is designed to be stable with low-ESR ceramic capacitors, which helps reduce the total footprint on the PCB. * **Protection Circuits:** * **Internal Current Limit:** Protects the device if the load draws too much current. * **Thermal Shutdown:** Automatically turns off the device if it overheats. --- ### 3. Pinout Configuration (DFN6 Package) | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **OUT** | Regulated output voltage. | | 2 | **N/C** | No internal connection. | | 3 | **GND** | Ground reference. | | 4 | **EN** | Enable control (High = On, Low = Off). | | 5 | **ADJ/NC** | Adjust pin (for ADJ version) or No connection. | | 6 | **IN** | Input voltage supply. | | **Exp. Pad** | **GND** | Exposed pad must be connected to Ground for thermal relief. | --- ### 4. Typical Application Circuit To use this part effectively, minimum external components are required: ```mermaid graph LR Vin((Vin)) --> C1[Cin: 1uF] C1 --> LDK220[LDK220PU-R] LDK220 --> C2[Cout: 1uF] C2 --> Vout((Vout)) EN_Signal --> LDK220 ``` ### 5. Common Use Cases * **Battery Powered Devices:** Due to low quiescent current. * **Post-regulation:** Cleaning up noise from switching DC-DC converters. * **Mobile/Handheld Electronics:** Small DFN package saves PCB real estate. * **Industrial Sensors:** High input voltage tolerance (up to 13.2V) allows for use in 12V systems. ---