## SD20-681-R: Electronic Component Overview The **SD20-681-R** is a low-profile, shielded surface-mount (SMD) power inductor. It is part of the SD20 series manufactured by **Eaton (formerly Bussmann/Coiltronics)**. These components are primarily used in power management circuits to store energy and filter noise. --- ### 1. Key Technical Specifications The model number "681" indicates the inductance value, while the "R" signifies RoHS compliance. | Parameter | Value / Specification | | :--- | :--- | | **Inductance** | 680 µH (Microhenries) | | **Tolerance** | ±20% | | **Current Rating (Irms)** | ~0.198 A (198 mA) | | **Saturation Current (Isat)** | ~0.203 A (203 mA) | | **DC Resistance (DCR)** | ~5.85 Ω (Max) | | **Operating Temperature** | -40°C to +125°C | | **Shielding** | Magnetically Shielded | | **Package Size** | 5.2mm x 5.2mm x 2.0mm | --- ### 2. Physical Design and Construction * **Magnetic Shielding:** The inductor is encapsulated in a ferrite drum core with a ferrite sleeve. This "shielding" minimizes Electromagnetic Interference (EMI), preventing the inductor's magnetic field from affecting nearby sensitive components on the PCB. * **Low Profile:** The "20" in the series name refers to its height (2.0mm). This makes it ideal for space-constrained applications like smartphones, wearables, and thin laptops. * **Construction:** It uses a high-grade ferrite core material that provides high efficiency and low core losses. --- ### 3. Common Applications Inductors like the SD20-681-R are essential in DC-to-DC conversion. Common use cases include: 1. **Buck/Boost Converters:** Helping to step down or step up voltages in battery-powered devices. 2. **EMI Filtering:** Smoothing out ripples in power supply lines to ensure clean power delivery. 3. **LED Drivers:** Managing current flow to high-brightness LEDs. 4. **Signal Processing:** Used in decoupling circuits to isolate different stages of an electronic system. --- ### 4. Part Number Breakdown ```text SD 20 - 681 - R | | | | | | | └── RoHS Compliant | | └──────── Inductance Code (68 x 10^1 = 680 µH) | └───────────── Size Code (Height: 2.0mm) └───────────────── Series Name (Shielded Drum) ```