## Technical Overview of SD20-471-R The **SD20-471-R** is a high-performance, low-profile, shielded surface-mount (SMD) power inductor. It is part of the SD series manufactured by **Eaton (formerly Cooper Bussmann)**. These inductors are widely used in power management circuits due to their compact size and electromagnetic interference (EMI) shielding. --- ### 1. Key Technical Specifications The alphanumeric code "471" represents the inductance value. Here is the detailed breakdown of its electrical characteristics: | Parameter | Specification | | :--- | :--- | | **Inductance** | 470 µH | | **Tolerance** | ±20% | | **DC Resistance (DCR)** | ~1.85 Ω (Typical) | | **Rated Current ($I_{rms}$)** | ~0.267 Amperes | | **Saturation Current ($I_{sat}$)** | ~0.292 Amperes | | **Package Size** | 5.2mm x 5.2mm | | **Height** | 2.0mm (Low Profile) | | **Shielding** | Shielded (Magnetic) | --- ### 2. Component Composition The SD20-471-R is built using specific materials to optimize power efficiency: * **Ferrite Core:** The heart of the inductor, designed to provide high magnetic permeability while minimizing energy loss. * **Magnet Wire:** Copper winding around the core that determines the DC resistance. * **Magnetic Shielding:** The assembly is encased in a magnetic material that contains the magnetic flux. This prevents the inductor from interfering with nearby sensitive components and reduces audible noise. * **Termination:** Matte tin-over-copper plating, making it compatible with lead-free reflow soldering processes. --- ### 3. Applications and Use Cases Because of its high inductance (470 µH) and small footprint, the SD20-471-R is typically found in: 1. **DC-DC Converters:** Used as an energy storage element in buck (step-down) or boost (step-up) converters. 2. **EMI Filtering:** Excellent for smoothing out ripples in power supplies and filtering high-frequency noise. 3. **Battery Powered Devices:** Ideal for IoT sensors, handheld medical devices, and wearables where board space is limited. 4. **LED Drivers:** Provides constant current regulation in small-scale lighting applications. --- ### 4. Part Number Breakdown Understanding the nomenclature helps in selecting alternates: * **SD:** Product Series (Shielded Drum Core). * **20:** Dimensional size (approx. 2.0mm height). * **471:** Inductance code ($47 \times 10^1 = 470$ µH). * **R:** RoHS compliant (Lead-free).