The **ADP2503ACPZ-3.3-R7** is a high-efficiency, low-quiescent-current **Buck-Boost DC-to-DC Regulator** manufactured by Analog Devices (ADI). It is specifically designed for applications where the input voltage can be higher, lower, or equal to the output voltage. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Output Voltage** | Fixed 3.3 V | | **Input Voltage Range** | 2.3 V to 5.5 V | | **Output Current** | Up to 600 mA | | **Switching Frequency** | 2.5 MHz | | **Quiescent Current** | 38 µA (Power Save Mode) | | **Efficiency** | Up to 95% | | **Package** | 10-lead LFCSP (3mm x 3mm) | --- ### 2. Core Features and Functionality #### A. Buck-Boost Architecture Unlike standard step-down (Buck) or step-up (Boost) converters, the ADP2503 uses a proprietary architecture that provides a seamless transition between modes. This is critical for battery-operated devices where a Lithium-ion battery voltage drops from ~4.2V (fully charged) to ~2.7V (discharged). The device ensures a steady 3.3V throughout the entire discharge cycle. #### B. High Switching Frequency (2.5 MHz) The high frequency allows for the use of very small inductors and ceramic capacitors, reducing the overall PCB footprint. This makes it ideal for space-constrained mobile electronics. #### C. Operational Modes * **PWM Mode:** Constant frequency for low noise and easy filtering. * **PSM (Power Save Mode):** Automatically enters this mode at light loads to increase efficiency and extend battery life. --- ### 3. Pin Configuration Overview | Pin No. | Name | Description | | :--- | :--- | :--- | | 1 | **VOUT** | Regulated Output Voltage (3.3V). | | 2 | **PGND** | Power Ground. | | 3, 4 | **SW1/SW2** | Switch nodes connected to the power inductor. | | 5 | **VIN** | Input Supply Voltage. | | 6 | **EN** | Enable pin (High = ON, Low = Shutdown). | | 7 | **SYNC** | Frequency Synchronization / Mode Select. | --- ### 4. Typical Application Circuit The implementation requires minimal external components, typically comprising an inductor and two capacitors. ```markdown [VIN] ----[Cin]---- (ADP2503) ----[L1]---- [VOUT] | | [GND] [Cout] ``` * **Inductor (L1):** Typically 1.0 µH to 1.5 µH. * **Capacitors (Cin/Cout):** Low ESR ceramic capacitors (typically 10 µF). --- ### 5. Common Applications * **Handheld Wireless Devices:** Smartphones and tablets. * **USB Powered Peripherals:** Devices requiring a stable 3.3V rail from a fluctuating 5V USB source. * **Sensors:** Remote IoT sensors powered by single-cell Li-ion batteries.