The **SDQ25-330-R** is a specific surface-mount (SMD) power inductor part of the **SDQ series** manufactured by Eaton (formerly Bussmann). It is unique because it is a **dual-winding inductor**, meaning it contains two separate coils within a single package. --- ### 1. Key Technical Specifications The part number "SDQ25-330-R" can be broken down to understand its characteristics: | Parameter | Specification | Description | | :--- | :--- | :--- | | **Inductance** | 33.0 µH | Rated inductance per winding. | | **Series/Size** | SDQ25 | Package size (approx. 5.2 x 5.2 x 2.5 mm). | | **Tolerance** | ±20% | Standard industrial tolerance. | | **DCR (Max)** | 0.385 Ω | Direct Current Resistance per winding. | | **Irms (Amps)** | 0.73 A | RMS Current for a 40°C temperature rise. | | **Isat (Amps)** | 0.81 A | Saturation Current (where inductance drops 30%). | | **Configuration** | Dual Winding | Two identical coils on one core. | --- ### 2. Functional Characteristics The "Dual Winding" nature of this component allows it to be used in several different circuit topologies: * **1:1 Transformer:** Since both coils are identical, it can act as a miniature isolation transformer. * **Coupled Inductor:** Used in SEPIC (Single-Ended Primary-Inductor Converter) or Zeta DC-DC converters to improve efficiency and reduce ripple. * **Series Connection:** Connecting the two coils in series quadruples the inductance ($L_{total} = L_1 + L_2 + 2M$). * **Parallel Connection:** Connecting them in parallel keeps the inductance the same but doubles the current handling capability. * **Common Mode Choke:** It can be used to filter electromagnetic interference (EMI) on power lines. --- ### 3. Physical & Material Properties * **Shielding:** It is magnetically shielded, which minimizes EMI and prevents interference with nearby sensitive components on the PCB. * **Construction:** Ferrite core with copper windings. * **Compliance:** The "-R" suffix indicates that the part is **RoHS compliant** (lead-free). * **Footprint:** Small SMT (Surface Mount Technology) footprint, ideal for high-density mobile or industrial boards. --- ### 4. Common Applications * **DC-DC Converters:** Specifically Buck, Boost, and SEPIC topologies. * **Battery Powered Equipment:** Due to its small size and high efficiency. * **Filtering:** Used in power supply input/output filters to remove high-frequency noise.