The **SDQ25-102-R** is a specific type of electronic component known as a **Dual Winding Toroidal Inductor (or Transformer)**. It is part of the SDQ series manufactured by Eaton (formerly Cooper Bussmann/Coiltronics). These components are unique because they contain two identical windings on a single core, allowing them to be configured in multiple ways depending on the circuit requirements. --- ### 1. Key Technical Specifications Below are the primary electrical characteristics for the SDQ25-102-R: | Parameter | Specification | | :--- | :--- | | **Inductance (L)** | 1.0 $\mu$H | | **Tolerance** | ±20% | | **DC Resistance (DCR)** | ~0.012 $\Omega$ (Parallel) / ~0.048 $\Omega$ (Series) | | **RMS Current ($I_{rms}$)** | ~6.5 Amps (Parallel configuration) | | **Peak Current ($I_{sat}$)** | ~10.4 Amps (Parallel configuration) | | **Mounting Type** | Surface Mount (SMD) | | **Operating Temp** | -40°C to +125°C | --- ### 2. Configuration Options Because the device has two separate windings, it can be wired in three primary ways: 1. **Parallel Mode:** Connect start-to-start and finish-to-finish. This maintains the base inductance ($1.0 \mu$H) but doubles the current handling capability. 2. **Series Mode:** Connect the finish of winding 1 to the start of winding 2. This quadruples the inductance ($4.0 \mu$H) but keeps the current rating of a single winding. 3. **1:1 Transformer Mode:** Use one winding as the primary and the other as the secondary. This provides galvanic isolation. --- ### 3. Construction and Materials * **Core Material:** Ferrite. This ensures high efficiency and low core losses at high frequencies. * **Shielding:** It is a **shielded** design, which minimizes EMI (Electromagnetic Interference) and prevents the magnetic field from affecting nearby sensitive components. * **Form Factor:** The "25" in the part number refers to the physical size (approx. 10mm x 10mm footprint). --- ### 4. Common Applications The SDQ25-102-R is commonly found in power management circuits, specifically: * **SEPIC Converters:** (Single-Ended Primary-Inductor Converters) where two inductors are needed. * **Buck/Boost Converters:** Used for voltage regulation in battery-powered devices. * **Common Mode Chokes:** Used for filtering noise out of power lines. * **Energy Storage:** In high-frequency DC-DC power supplies. ---