## Technical Overview: DR1040-3R8-R The **DR1040-3R8-R** is a high-power, shielded surface-mount (SMT) inductor manufactured by **Eaton (formerly Coiltronics)**. It is part of the DR series, specifically designed for high-density applications requiring low electromagnetic interference (EMI). ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Inductance** | 3.8 µH | | **Tolerance** | ±20% | | **DC Resistance (DCR)** | 11.2 mΩ (Typical) | | **Saturation Current ($I_{sat}$)** | 6.55 A | | **RMS Current ($I_{rms}$)** | 5.43 A | | **Operating Temperature** | -40°C to +125°C | | **Shielding** | Magnetically Shielded | | **Package Size** | 10.3mm x 10.5mm x 4.0mm | --- ### 2. Core Features & Construction * **Magnetic Shielding:** The component is enclosed in a ferrite drum core and sleeve. This design minimizes stray magnetic fields, preventing interference with surrounding sensitive components on a PCB. * **High Efficiency:** With a low DC Resistance (DCR) of approximately 11.2 mΩ, it minimizes power loss due to heat ($I^2R$ losses), making it ideal for high-efficiency power converters. * **Ferrite Core Material:** The use of ferrite ensures stable performance across high frequencies, typically utilized in switching power supplies. --- ### 3. Common Applications The DR1040-3R8-R is primarily used as an energy storage element or a filter in the following circuits: 1. **DC-DC Converters:** Buck (step-down), Boost (step-up), and SEPIC topologies. 2. **Voltage Regulator Modules (VRMs):** Used in computing and server environments to provide stable power to CPUs/GPUs. 3. **Battery Powered Devices:** Due to its high efficiency and compact size. 4. **LED Drivers:** Providing constant current for high-brightness lighting systems. --- ### 4. Part Number Breakdown The nomenclature `DR1040-3R8-R` can be decoded as follows: * **DR:** Product Series (Drum Core, Shielded). * **1040:** Physical Dimensions (Approx. 10mm width/length and 4.0mm height). * **3R8:** Inductance value ($3.8$ µH). The "R" acts as the decimal point. * **-R:** RoHS compliant (Lead-free). ---