## Technical Overview of SD18-102-R The **SD18-102-R** is a high-power density, low-profile SMT (Surface Mount Technology) power inductor manufactured by **Eaton (formerly Bussmann/Coiltronics)**. It is part of the SD series, designed for applications where space is limited and efficiency is critical. --- ### 1. Key Technical Specifications Below are the primary electrical and physical characteristics of the component: | Parameter | Specification | | :--- | :--- | | **Inductance** | 1000 µH (1.0 mH) | | **Tolerance** | ±20% | | **Current Rating (Irms)** | 0.162 Amps (162 mA) | | **Saturation Current (Isat)** | 0.158 Amps (158 mA) | | **DC Resistance (DCR)** | 4.86 Ohms (Max) | | **Operating Temperature** | -40°C to +125°C | | **Dimensions (L x W x H)** | 5.2mm x 5.2mm x 1.8mm | | **Shielding** | Ferrite Shielded (Magnetic) | --- ### 2. Core Components and Materials The "Electronic Parts" or internal structure of this inductor consist of: 1. **Ferrite Drum Core:** This acts as the magnetic carrier. Ferrite is used to provide high magnetic permeability while keeping eddy current losses low at high frequencies. 2. **Copper Wire Winding:** A precision-wound copper coil creates the inductance. In the "102" (1000µH) version, the wire is very thin with many turns, leading to a higher DCR compared to lower inductance values in the same series. 3. **Magnetic Shield (Ring):** The inductor is "shielded," meaning it has a ferrite sleeve around the coil. This prevents electromagnetic interference (EMI) from leaking out and affecting nearby sensitive components. 4. **Terminations:** Solder pads made of tin-plated copper for stable SMT mounting on PCBs. --- ### 3. Decoding the Part Number The name follows a specific nomenclature used by Eaton: * **SD:** Series name (Shielded Drum Inductor). * **18:** Size code (refers to the 1.8mm height profile). * **102:** Inductance code. The first two digits (10) are the value, and the third (2) is the multiplier (10 * 10^2 = 1000µH). * **-R:** RoHS compliant (Lead-free). --- ### 4. Common Applications Due to its high inductance and small form factor, it is typically used in: * **DC-DC Converters:** Buck, Boost, and SEPIC topologies. * **Filtering:** Noise suppression in power lines for handheld electronics. * **LED Drivers:** Providing constant current for low-power lighting. * **Battery Powered Devices:** IoT sensors, wearables, and medical instruments.