The **AMPLH4020S-R47M** is a high-performance, shielded power inductor typically used in DC-DC converter circuits. It belongs to a class of surface-mount devices (SMD) designed for high-current applications with minimal electromagnetic interference (EMI). --- ### 1. Part Number Breakdown Understanding the nomenclature helps identify the physical and electrical characteristics of the component: | Segment | Meaning | Description | | :--- | :--- | :--- | | **AMPLH** | Series | Molded High-Current Power Inductor series. | | **4020** | Size Code | Dimensions: Approx. **4.0mm x 4.0mm** with a height of **2.0mm**. | | **S** | Type/Standard | Often denotes the specific construction style (e.g., standard profile). | | **R47** | Inductance | **0.47 µH** (Microhenries). | | **M** | Tolerance | **±20%** tolerance. | --- ### 2. Key Electrical Specifications While exact values can vary slightly by manufacturer (e.g., Abracon or similar), the general specifications for a 4020-size 0.47µH inductor are: * **Inductance:** 0.47 µH. * **DC Resistance (DCR):** Extremely low (typically between 5mΩ to 15mΩ) to minimize power loss. * **Saturation Current ($I_{sat}$):** The current at which inductance drops by a specified percentage (usually 30%). For this part, it is typically in the **9A to 13A** range. * **Heating Current ($I_{rms}$):** The continuous current that causes a 40°C temperature rise. Typically around **7A to 10A**. * **Operating Temperature:** Generally rated from **-40°C to +125°C**. --- ### 3. Construction & Features * **Molded Shielding:** The coil is encapsulated in a metallic magnetic iron powder. This "molded" construction provides excellent magnetic shielding, reducing EMI compared to traditional wire-wound inductors. * **High Saturation:** The metal powder core allows for "soft saturation," meaning the inductor maintains performance even during high-current spikes. * **Compact Footprint:** The 4020 package is ideal for space-constrained designs like smartphones, tablets, and thin laptops. --- ### 4. Common Applications This inductor is primarily used in **Voltage Regulator Modules (VRMs)** and **Point of Load (POL)** converters for: 1. **Consumer Electronics:** Powering CPUs and GPUs in portable devices. 2. **Telecommunications:** Base station power supplies. 3. **Industrial:** High-efficiency DC-DC step-down (Buck) converters.