The **SDR1045 series** (specifically often referenced as part of the Bourns SDR1045 family) consists of surface-mount (SMD) power inductors. These components are essential in power management circuits for energy storage and noise filtering. Below is a detailed technical breakdown of the SDR1045 series electronics parts. --- ### 1. General Specifications The SDR1045 series is characterized by its physical size and construction. The "1045" suffix typically indicates the dimensions: approximately **10 mm x 10 mm** in footprint and **4.5 mm** in height. | Feature | Specification | | :--- | :--- | | **Component Type** | Non-shielded Power Inductor | | **Inductance Range** | 1.0 $\mu$H to 1000 $\mu$H | | **Operating Temperature** | -40 °C to +125 °C | | **Construction** | Ferrite Drum Core | | **Termination** | Lead-free (RoHS compliant) | --- ### 2. Key Electrical Parameters When selecting an SDR1045 part, engineers focus on three primary metrics: * **Inductance ($L$):** Measured in Microhenries ($\mu$H). This determines the energy storage capacity. * **DCR (DC Resistance):** The internal resistance of the copper wire. Lower DCR is preferred to minimize heat loss and maximize efficiency. * **Isat (Saturation Current):** The current level at which the inductance drops by a specific percentage (usually 10-30%). * **Irms (RMS Current):** The continuous current that causes a specific temperature rise (usually 40 °C) in the component. --- ### 3. Comparison of Common Values Here is a sample table showing how electrical characteristics change based on the inductance value within the SDR1045 series: | Part Number (Example) | Inductance ($\mu$H) | DCR Max ($\Omega$) | Irms (A) | Isat (A) | | :--- | :--- | :--- | :--- | :--- | | SDR1045-1R0M | 1.0 | 0.005 | 9.00 | 11.00 | | SDR1045-100M | 10.0 | 0.025 | 4.50 | 4.40 | | SDR1045-101K | 100.0 | 0.220 | 1.50 | 1.35 | | SDR1045-102K | 1000.0 | 2.500 | 0.45 | 0.40 | --- ### 4. Applications The SDR1045 series is commonly found in the following electronic circuits: 1. **DC-DC Converters:** Used in buck (step-down) or boost (step-up) regulators to smooth current. 2. **Power Supplies:** Found in laptops, telecommunications equipment, and consumer electronics. 3. **Input/Output Filters:** Used to reduce electromagnetic interference (EMI) and ripple voltage. --- ### 5. Part Numbering Nomenclature The suffix usually provides specific details about the tolerance and packaging: * **M:** ±20% Tolerance * **K:** ±10% Tolerance * **L:** Refers to RoHS compliance or specific lead-free plating.