## Analysis of FP3-4R7-R Inductor The **FP3-4R7-R** is a high-frequency, high-current power inductor typically used in DC-DC converters and voltage regulator modules (VRMs). It is part of the **FP3 Series** manufactured by **Eaton (formerly Cooper Bussmann/Coiltronics)**. --- ### 1. Part Number Breakdown Understanding the nomenclature helps identify the specifications: | Segment | Meaning | Detail | | :--- | :--- | :--- | | **FP3** | Series Name | Flat-Pac™ 3 Surface Mount Inductor | | **4R7** | Inductance Value | 4.7 Microhenries ($\mu H$) | | **-R** | Compliance | RoHS Compliant | --- ### 2. Key Specifications These parts are designed for high power density and efficiency. * **Inductance:** $4.7 \mu H$ * **Current Rating (Typical):** Ranges from 3.5A to 5A depending on the specific thermal conditions. * **DC Resistance (DCR):** Low DCR (typically in the tens of milliohms) to minimize power loss. * **Operating Temperature:** Generally $-40^\circ C$ to $+125^\circ C$. * **Construction:** Ferrite core material with a flat-wire design to reduce "skin effect" losses at high frequencies. --- ### 3. Physical Attributes The "Flat-Pac" design is optimized for automated assembly and space-constrained boards. * **Footprint:** Surface Mount Device (SMD). * **Shielding:** Usually magnetically shielded to reduce Electromagnetic Interference (EMI) with neighboring components. * **Dimensions:** Small form factor (approx. $7.2mm \times 6.7mm$ base). --- ### 4. Common Applications Due to its high current handling and low loss, the FP3-4R7-R is found in: 1. **Multi-phase Regulators:** Powering CPUs and GPUs. 2. **Point-of-Load (POL) Converters:** Converting 12V or 5V rails to lower voltages for digital ICs. 3. **Battery Powered Systems:** Where efficiency is critical to extending battery life. 4. **Networking Equipment:** Routers and switches requiring stable power delivery. --- ### 5. Technical Considerations When integrating this part into a circuit, pay attention to the **Saturation Current ($I_{sat}$)**. This is the point where the inductance drops by a certain percentage (usually 20-30%). Exceeding this limit will cause the inductor to lose its properties, potentially leading to circuit failure or overheating.