The **SD18-4R7-R** is a high-power density, low-profile surface mount (SMD) inductor. It is part of the SD series manufactured by **Eaton (formerly Cooper Bussmann/Coiltronics)**. This component is primarily used for energy storage and filtering in power management circuits. --- ## 1. Technical Specifications The following table highlights the primary electrical and physical characteristics of the SD18-4R7-R: | Parameter | Specification | | :--- | :--- | | **Inductance** | 4.7 µH | | **Tolerance** | ±20% | | **Rated Current (Isat)** | 2.14 A (Saturation Current) | | **RMS Current (Irms)** | 1.95 A (Temperature Rise Current) | | **DC Resistance (DCR)** | 0.0528 Ω (Typical) | | **Operating Temperature** | -40°C to +125°C | | **Package Size** | 5.2mm x 5.2mm x 1.8mm | | **Shielding** | Ferrite Drum Core (Magnetically Shielded) | --- ## 2. Key Features & Construction * **Magnetic Shielding:** The inductor is designed with a closed magnetic path, which minimizes Electromagnetic Interference (EMI) and prevents the component from affecting nearby sensitive components. * **Low Profile:** With a height of only 1.8mm, it is ideal for slim electronic devices like smartphones, tablets, and wearable tech. * **Ferrite Core:** Utilizes a ferrite core material that offers high efficiency and low core losses at high frequencies. * **RoHS Compliant:** The "-R" suffix indicates that the part is lead-free and meets RoHS environmental standards. --- ## 3. Common Applications This part is typically found in DC-DC converter circuits. Specific use cases include: * **Buck/Boost Converters:** Step-down or step-up voltage regulation. * **Battery Powered Devices:** Optimizing power delivery in portable electronics. * **LED Drivers:** Providing constant current for lighting applications. * **Computer Peripherals:** Used in HDDs, SSDs, and motherboard power phases. --- ## 4. Part Number Breakdown The nomenclature follows a specific logic: ```text SD 18 - 4R7 - R | | | | | | | └-- RoHS Compliant | | └------- Inductance Value (4.7 µH) | └------------- Size Code (Dimensions/Height) └------------------ Series Name (Shielded Drum) ```