The **FP1308R1-R21-R** is a high-current, shielded drum core power inductor typically used in DC-DC converters and voltage regulator modules (VRMs). It is part of the FP1308 series manufactured by Eaton (formerly Cooper Bussmann/Coiltronics). --- ### 1. Part Number Breakdown Understanding the nomenclature helps identify its specific electrical characteristics: | Segment | Meaning | Description | | :--- | :--- | :--- | | **FP1308** | Product Series | High-frequency, high-current power inductor series (13x8mm footprint). | | **R1** | Revision/Style | Indicates a specific mechanical or material revision. | | **R21** | Inductance Value | **0.21 µH** (R denotes the decimal point). | | **-R** | RoHS Compliant | Lead-free and compliant with environmental standards. | --- ### 2. Key Specifications The "R21" variant is optimized for high-speed switching and extremely high current density. | Parameter | Value (Approx.) | | :--- | :--- | | **Inductance** | 0.21 µH | | **Isat (Saturation Current)** | ~64 Amperes (the point where inductance drops by 20%) | | **Irms (Heating Current)** | ~53 Amperes (based on a 40°C temperature rise) | | **DCR (DC Resistance)** | ~0.41 mΩ (Milliohms) — extremely low for efficiency | | **Operating Temp** | -40°C to +125°C | --- ### 3. Core Features and Materials * **Ferrite Core Material:** Provides low core losses at high frequencies, making it ideal for modern power supplies. * **Shielded Construction:** The inductor is magnetically shielded to minimize Electromagnetic Interference (EMI) with neighboring components. * **Low DCR:** The extremely low resistance minimizes power wasted as heat, which is critical for high-efficiency mobile or server hardware. --- ### 4. Typical Applications Because of its high current rating and small form factor, this part is commonly found in: 1. **Multi-phase Buck Regulators:** Used to power CPUs, GPUs, and ASICs. 2. **Voltage Regulator Modules (VRM):** Standard in server motherboards and high-end desktop PCs. 3. **Point of Load (POL) Converters:** Decentralized power management on complex PCBs. 4. **High-Current Power Supplies:** Used in telecommunications and networking equipment. --- ### 5. Footprint and Mounting The FP1308 series typically features a surface-mount (SMD) design with dimensions approximately **13.4mm x 8.0mm x 8.0mm**. The rugged construction is designed to withstand the high temperatures of reflow soldering.