The **FP1309B1-R120-R** is a high-current, shielded drum core power inductor manufactured by **Eaton (formerly Cooper Bussmann)**. It belongs to the FP1309 series, which is specifically designed for high-frequency voltage regulator modules (VRMs). --- ### 1. Key Technical Specifications The part number can be broken down to understand its specific electronic characteristics: | Parameter | Specification | | :--- | :--- | | **Inductance** | 120 nH (0.120 µH) | | **Tolerance** | ±10% | | **Current Rating ($I_{rms}$)** | 61 Amps | | **Saturation Current ($I_{sat}$)** | 91 Amps | | **DC Resistance (DCR)** | 0.220 mΩ (Typical) | | **Operating Temperature** | -40°C to +125°C | | **Size / Dimension** | 13.4mm x 9.0mm x 9.0mm | --- ### 2. Physical Construction and Design The inductor utilizes a specialized construction to handle extreme current densities: * **Shielded Construction:** The part is magnetically shielded to minimize Electromagnetic Interference (EMI), which is critical in densely packed PCB environments. * **Ferrite Core Material:** It uses a high-frequency ferrite material characterized by low core losses, making it efficient for switching frequencies up to 2 MHz. * **Flat Wire Technology:** The "FP" in the series often refers to the use of flat wire or high-surface-area conductors to minimize the **Skin Effect** and reduce DCR, allowing for higher current handling in a smaller footprint. --- ### 3. Application Use Cases This component is typically found in high-performance power stages where high efficiency and high current are required: 1. **Multi-phase Buck Converters:** Used as the output inductor for CPU/GPU power supplies (Vcore). 2. **Voltage Regulator Modules (VRMs):** Found on high-end server motherboards and graphics cards. 3. **Point-of-Load (POL) Converters:** Used in telecommunications and data center equipment to step down voltage locally. --- ### 4. Part Number Decoder ```text FP1309B1 - R120 - R | | | | | +-- RoHS Compliant | +--------- Inductance Value (R120 = 0.120µH) +------------------- Series & Size (13.4 x 9.0 x 9.0 mm) ``` ---