### Technical Overview: SDR1045-331K The **SDR1045-331K** is a specific model of a **Surface Mount Device (SMD) Power Inductor** manufactured by **Bourns Inc.** It is designed for high-density power applications where space is limited but reliability is required. --- ### 1. Part Number Breakdown Understanding the alphanumeric code helps identify the component's specifications: | Part Segment | Meaning | Value / Description | | :--- | :--- | :--- | | **SDR** | Series Name | Standard SMD Power Inductor | | **1045** | Physical Size | Approx. 10mm (Diameter) x 4.5mm (Height) | | **331** | Inductance Code | $33 \times 10^1 = 330$ | | **K** | Tolerance | $\pm 10\%$ | --- ### 2. Key Specifications The electronic characteristics define how the part performs within a circuit: * **Inductance:** $330 \mu H$ (Microhenries). * **Tolerance:** $\pm 10\%$. * **DC Resistance (DCR):** Usually around $0.92 \Omega$ (Max). This determines the power loss (heat) within the inductor. * **Rated Current ($I_{rms}$):** Approximately $0.52 A$. This is the continuous current it can handle without overheating. * **Saturation Current ($I_{sat}$):** Approximately $0.62 A$. This is the point where the inductance drops significantly. --- ### 3. Construction and Materials The SDR1045-331K is built using a non-shielded design: * **Core Material:** Ferrite. This allows for high magnetic permeability and efficiency at high frequencies. * **Winding:** Enamelled copper wire wound around a drum-shaped core. * **Terminals:** Lead-free tin (Sn) plating over a nickel (Ni) barrier, suitable for reflow soldering. * **Form Factor:** "Unshielded" or "Semi-shielded." This means the magnetic field is not fully contained, which is cheaper but can cause Electromagnetic Interference (EMI) with nearby components. --- ### 4. Typical Applications This component is commonly found in power management stages: 1. **DC-DC Converters:** Used in Buck or Boost converters to store energy. 2. **Power Supplies:** Filtering noise in LCD televisions, notebooks, and portable devices. 3. **Filtering:** Used in signal lines to block high-frequency noise while allowing DC to pass. --- ### 5. Summary Table | Feature | Specification | | :--- | :--- | | **Inductance** | 330 $\mu$H | | **Max DCR** | 0.92 Ohms | | **Test Frequency** | 1 kHz / 1V | | **Operating Temp** | -40°C to +125°C | | **Mounting Type** | Surface Mount (SMD) |