## Overview of ADP2504ACPZ-2.8-R7 The **ADP2504ACPZ-2.8-R7** is a high-efficiency, low quiescent current, step-up/step-down (buck-boost) DC-to-DC converter produced by **Analog Devices**. It is specifically designed for applications where the input voltage can be higher than, lower than, or equal to the output voltage. --- ### Key Specifications | Feature | Specification | | :--- | :--- | | **Output Voltage (Fixed)** | 2.8 V | | **Input Voltage Range** | 2.3 V to 5.5 V | | **Output Current** | Up to 600 mA | | **Switching Frequency** | 2.5 MHz | | **Package** | 10-lead LFCSP (3mm x 3mm) | | **Operating Temperature** | -40°C to +125°C | | **Efficiency** | Up to 95% | --- ### Core Electronic Characteristics #### 1. Buck-Boost Topology This part uses a four-switch architecture. This allows the device to transition seamlessly between buck mode (stepping down voltage) and boost mode (stepping up voltage). This is critical for battery-powered devices where a Li-ion battery voltage drops from 4.2V down to 2.5V while requiring a steady 2.8V output. #### 2. High Switching Frequency The **2.5 MHz** frequency allows for the use of very small, low-profile inductors and ceramic capacitors. This minimizes the total PCB footprint, making it ideal for space-constrained electronics like smartphones or wearables. #### 3. Power Saving Modes * **PWM Mode:** Operates at a fixed frequency for low noise and low output ripple. * **PSM (Power Save Mode):** Automatically enters this mode at light loads to increase efficiency by reducing the switching frequency. #### 4. Safety and Protection Features * **Thermal Shutdown:** Protects the chip from overheating. * **Short-Circuit Protection:** Prevents damage during fault conditions. * **Under-Voltage Lockout (UVLO):** Ensures the device doesn't operate at unstable low input voltages. --- ### Typical Application Circuit Parts To implement this IC in a design, the following external components are typically required: 1. **Inductor ($L$):** Usually a 1.0 $\mu$H to 1.5 $\mu$H power inductor. 2. **Input Capacitor ($C_{IN}$):** Typically a 10 $\mu$F ceramic capacitor to stable the input. 3. **Output Capacitor ($C_{OUT}$):** Typically a 10 $\mu$F to 22 $\mu$F ceramic capacitor to reduce ripple. 4. **Enable (EN):** A logic pin to turn the converter on or off. --- ### Example Pinout Summary | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | VIN | Input Power Supply | | 4 | VOUT | Regulated Output Voltage | | 5 | GND | Ground Reference | | 10 | EN | Enable Pin (High = On) |