### Technical Overview of SD18-1R2-R The **SD18-1R2-R** is a high-power density, low-profile SMT (Surface Mount Technology) power inductor. It is part of the SD series manufactured by **Eaton (formerly Bussmann)**. These inductors are primarily used in DC-DC converters and power management circuits where space is limited but high efficiency is required. --- ### Key Specifications | Feature | Specification | | :--- | :--- | | **Inductance** | 1.2 µH | | **Tolerance** | ±20% | | **Rated Current (Irms)** | 3.56 Amps | | **Saturation Current (Isat)** | 4.64 Amps | | **DC Resistance (DCR)** | 0.0215 Ω (21.5 mΩ) Typical | | **Package / Case** | 5.2mm x 5.2mm x 1.8mm | | **Operating Temp** | -40°C to +125°C | --- ### Core Electronic Characteristics #### 1. Ferrite Core Construction The device uses a ferrite core, which provides a closed magnetic path. This design results in: * **Low EMI:** Minimal electromagnetic interference due to the shielded construction. * **High Efficiency:** Lower core losses at high frequencies compared to iron powder cores. #### 2. Power Handling * **Irms (Root Mean Square Current):** This represents the continuous DC current the inductor can carry while maintaining a temperature rise of roughly 40°C. * **Isat (Saturation Current):** This is the point where the inductance drops by a specific percentage (usually 30%). For the 1R2-R, it can handle spikes up to 4.64A before the magnetic material "saturates" and loses its inductive properties. #### 3. Low Profile Design The "18" in the part number refers to the height (1.8mm). This makes it ideal for: * Mobile phones and handheld electronics. * Slim laptop/tablet power rails. * LED driver circuits. --- ### Part Number Breakdown | Segment | Meaning | | :--- | :--- | | **SD** | Series Name (Shielded Drum) | | **18** | Size/Height Code (1.8mm height) | | **1R2** | Inductance Value (1.2 microhenries) | | **-R** | RoHS Compliant | --- ### Applications The SD18-1R2-R is commonly integrated into the following circuits: 1. **Buck/Boost Converters:** Stepping voltage up or down in battery-powered devices. 2. **Computer Peripherals:** Powering hard drives or GPU sub-sections. 3. **Filtering:** Removing high-frequency noise from power supply lines.