## Overview of the DRQ125-331-R The **DRQ125-331-R** is a high-power, shielded dual-winding inductor (coupled inductor) manufactured by **Eaton (formerly Bussmann/Coiltronics)**. It is part of the DRQ series, known for high efficiency and compact surface-mount design. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Inductance (L)** | 330 µH (nominal) | | **Tolerance** | ±20% | | **DC Resistance (DCR)** | 0.902 Ω (Maximum) | | **Rated Current (Irms)** | 0.77 Amps | | **Saturation Current (Isat)** | 0.96 Amps | | **Operating Temperature** | -40°C to +125°C | | **Mounting Type** | Surface Mount (SMD/SMT) | | **Shielding** | Magnetically Shielded | --- ### 2. Physical Construction and Pins The DRQ125 series features a **dual-winding** configuration. This means there are two separate coils wound onto a single core. * **Four Terminals:** The device has four pads. Depending on how you connect these pads on your PCB, the inductor's behavior changes. * **Dimensions:** Roughly 12.5mm x 12.5mm with a height of 6.0mm. * **Shielding:** The magnetic shielding minimizes Electromagnetic Interference (EMI), making it suitable for noise-sensitive environments. --- ### 3. Circuit Configurations Because it has two windings, the DRQ125-331-R is versatile. It can be used in three primary ways: #### A. Series Connection By connecting the two coils in series, you increase the total inductance. * **Total Inductance:** $L_{total} \times 4$ (Approx. 1320 µH). * **Usage:** High-voltage applications where high inductance is required. #### B. Parallel Connection By connecting the two coils in parallel, the inductance stays the same as a single winding, but the current capacity increases. * **Current Capacity:** $I_{rms} \times 2$. * **Usage:** High-current power supplies. #### C. Coupled Inductor (Transformer Mode) Using the windings independently as a 1:1 transformer. * **Usage:** SEPIC converters, flyback converters, or Zeta converters. --- ### 4. Common Applications * **DC-DC Converters:** Specifically SEPIC and Flyback topologies. * **Power Supplies:** Used in industrial, computer, and consumer electronics. * **Energy Storage:** Acts as a filter or energy storage element in switching regulators. * **Battery Powered Systems:** High efficiency helps prolong battery life. ---