The **FP1108L4-R120-R** is a high-current, surface-mount (SMD) power inductor specifically designed for multi-phase voltage regulator modules (VRMs). It is part of the FP1108 series manufactured by **Eaton (formerly Cooper Bussmann/Coiltronics)**. ### 1. Key Technical Specifications The following table highlights the primary electrical and physical characteristics of this component: | Parameter | Specification | | :--- | :--- | | **Inductance ($L$)** | 120 nH (0.12 µH) | | **Tolerance** | ±10% | | **DC Resistance ($DCR$)** | 0.29 mΩ (Typical) | | **Saturation Current ($I_{sat}$)** | 84 A @ 25°C | | **RMS Current ($I_{rms}$)** | 61 A | | **Operating Temperature** | -40°C to +125°C | | **Package Dimensions** | 11.0mm x 8.0mm x 7.5mm | | **Material** | Ferrite core with flat-wire construction | --- ### 2. Core Features and Technology * **High Current Density:** Due to the extremely low DCR (0.29 mΩ), this inductor can handle very high currents with minimal power loss (heat dissipation). * **Ferrite Core Material:** The use of ferrite provides low core losses at high frequencies, which is critical for modern power supplies switching at hundreds of kHz or low MHz. * **Flat-Wire Construction:** Unlike traditional round-wire coils, flat-wire winding minimizes skin effect and proximity effect losses, allowing for a more compact footprint and better thermal performance. * **Tight Tolerance:** The "L4" in the part number often refers to specific mechanical or electrical binning, ensuring consistency in high-speed, multi-phase designs where current balancing is vital. --- ### 3. Common Applications This part is typically found in high-performance computing environments where high current and low voltage are required. 1. **Server CPU/GPU Power:** Used in Vcore power stages for Intel and AMD processors. 2. **Voltage Regulator Modules (VRM):** Critical in multi-phase buck converters to provide stable power to high-end graphics cards (GPUs). 3. **Data Centers:** Integrated into power distribution units and high-speed networking equipment. 4. **Point-of-Load (PoL) Converters:** Used in systems requiring high efficiency in a small physical space. --- ### 4. Part Number Breakdown The nomenclature for this series generally follows this logic: * **FP1108:** Series designation (11.0mm x 8.0mm footprint). * **L4:** Product revision or specific lead-frame configuration. * **R120:** Inductance value (R = decimal point; 120 = 0.120 µH). * **-R:** RoHS compliant.