## Detailed Analysis of SD12-R47-R Inductor The **SD12-R47-R** is a specific electronic component belonging to the family of **Surface Mount Device (SMD) Power Inductors**. It is part of the SD series manufactured by **Eaton (formerly Cooper Bussmann)**. --- ### 1. Key Technical Specifications The part number defines the physical and electrical characteristics of the component: | Parameter | Value | Description | | :--- | :--- | :--- | | **Inductance** | 0.47 µH | The nominal inductance value. | | **Tolerance** | ±20% | Deviation allowed from the nominal inductance. | | **Current Rating (Irms)** | ~3.0A to 4.0A | The RMS current that causes a 40°C temperature rise. | | **Saturation Current (Isat)** | ~4.5A to 5.5A | The peak current where inductance drops by 30%. | | **DC Resistance (DCR)** | ~0.025 Ω | The internal resistance of the copper winding. | | **Size / Dimension** | 5.2mm x 5.2mm x 1.2mm | Low-profile square footprint. | --- ### 2. Part Number Breakdown Understanding the nomenclature helps in identifying similar parts: * **SD**: Series name (Shielded Drum Core). * **12**: Size code (approximately 1.2mm in height). * **R47**: Inductance value (R represents the decimal point; 0.47 microhenries). * **-R**: RoHS compliant (lead-free). --- ### 3. Physical Construction & Features * **Shielded Design:** The inductor is magnetically shielded. This minimizes Electromagnetic Interference (EMI) with neighboring components, making it ideal for high-density circuit boards. * **Ferrite Core:** Utilizes a ferrite drum core for high efficiency and low core losses at high frequencies. * **Low Profile:** The "12" height (1.2mm) makes it suitable for ultra-thin electronics like smartphones, tablets, and wearables. --- ### 4. Common Applications Due to its low inductance and high current handling, it is typically used in: 1. **DC-DC Converters:** Buck, boost, and SEPIC converters. 2. **Power Management Units (PMICs):** Distributing power within mobile devices. 3. **Noise Filtering:** Removing high-frequency ripples from power lines. 4. **LED Drivers:** Providing stable current for backlighting. --- ### 5. Equivalent Replacement Considerations If you are looking for an alternative, ensure the following match: * **Footprint:** Must be 5.2mm x 5.2mm to fit the PCB pads. * **Saturation Current:** Replacing it with a part that has a lower `Isat` will cause the circuit to fail under load. * **DCR:** A higher DCR will result in more heat and lower battery efficiency.