The **SD12-221-R** is a high-power density, low-profile shielded drum core inductor manufactured by **Eaton (formerly Cooper Bussmann)**. It is part of the SD12 series, commonly used in power management applications where space is limited. --- ### 1. Technical Specifications The following table outlines the primary electrical and physical characteristics of the SD12-221-R: | Parameter | Value | | :--- | :--- | | **Inductance** | 220 µH | | **Tolerance** | ±20% | | **DC Resistance (DCR)** | 1.83 Ω (Typical) | | **Saturation Current ($I_{sat}$)** | 0.231 A | | **RMS Current ($I_{rms}$)** | 0.274 A | | **Shielding** | Magnetically Shielded | | **Package / Case** | 5.2mm x 5.2mm x 1.2mm | | **Mounting Type** | Surface Mount (SMD) | --- ### 2. Key Features * **Low Profile:** With a height of only 1.2mm, it is ideal for ultra-thin electronics like smartphones, tablets, and wearable tech. * **Magnetic Shielding:** The "shielded" design minimizes Electromagnetic Interference (EMI), preventing the inductor's magnetic field from affecting neighboring components. * **Ferrite Core:** Utilizes a ferrite drum core for high efficiency and stable performance across a wide frequency range. * **RoHS Compliant:** The "-R" suffix indicates that the part is lead-free and meets RoHS environmental standards. --- ### 3. Core Applications The SD12-221-R is typically found in the following circuits: 1. **DC-DC Converters:** Used as an energy storage element in buck, boost, or buck-boost regulators. 2. **Battery Powered Devices:** Ideal for handheld GPS units, digital cameras, and mobile phones due to its small footprint. 3. **EL Panels:** Often used in driver circuits for backlighting. 4. **Noise Filtering:** Acting as a low-pass filter to smooth out ripples in power supply lines. --- ### 4. Part Number Breakdown * **SD12:** Series identifier (5.2 x 5.2 x 1.2mm size). * **221:** Inductance code. The first two digits (22) are the value, and the third digit (1) is the multiplier ($10^1$). $22 \times 10 = 220$ µH. * **R:** Denotes RoHS compliance.