The **HCF1007-R42-R** is a high-current, power inductor typically used in DC-DC converter applications. It belongs to the HCF1007 series manufactured by **Eaton (formerly Bussmann/Coiltronics)**. ### 1. Key Technical Specifications The part number follows a specific nomenclature that defines its electrical characteristics: | Parameter | Value / Description | | :--- | :--- | | **Inductance** | 0.42 µH (Microhenries) | | **Tolerance** | ±20% | | **DC Resistance (DCR)** | ~0.48 mΩ (Max) | | **Saturation Current ($I_{sat}$)** | ~52 A (Amperes) | | **RMS Current ($I_{rms}$)** | ~35 A (Amperes) | | **Operating Temperature** | -40°C to +125°C | | **Package Size** | 10.3mm x 7.0mm x 6.4mm | --- ### 2. Physical & Material Features * **Core Material:** Ferrite core. This ensures low core losses at high switching frequencies. * **Construction:** High-current, shielded construction which minimizes Electromagnetic Interference (EMI). * **Terminal Finish:** Matte tin over copper, making it RoHS compliant and suitable for lead-free reflow soldering. * **Form Factor:** Surface Mount Device (SMD). --- ### 3. Applications Due to its high saturation current and low DCR, this inductor is primarily used in power management stages: 1. **Voltage Regulator Modules (VRMs):** Used in CPUs and GPUs where high current and low voltage are required. 2. **Point-of-Load (POL) Converters:** Providing localized power on motherboards. 3. **Multi-phase Buck Converters:** Used in servers and telecommunications equipment. 4. **High-density Power Supplies:** Where space is limited but power demands are high. --- ### 4. Part Number Breakdown The code `HCF1007-R42-R` can be decoded as follows: * **HCF:** High Current Ferrite series. * **1007:** Dimensions (approx. 10mm length x 7mm width). * **R42:** Inductance value (R = decimal point), so 0.42 µH. * **-R:** RoHS compliant. ---