## Overview of the DR73-3R3-R Inductor The **DR73-3R3-R** is a high-power density, shielded drum core inductor manufactured by **Eaton (formerly Coiltronics)**. It is part of the DR series, which is specifically designed for surface mount (SMD) applications requiring high efficiency and low electromagnetic interference (EMI). --- ### 1. Key Technical Specifications The following table outlines the primary electrical and physical characteristics of the DR73-3R3-R: | Parameter | Specification | | :--- | :--- | | **Inductance** | 3.3 µH | | **Tolerance** | ±20% | | **Current Rating (Irms)** | 3.96 Amps (Typical) | | **Saturation Current (Isat)** | 4.42 Amps (Typical) | | **DC Resistance (DCR)** | 0.0217 Ohms (Max) | | **Operating Temperature** | -40°C to +125°C | | **Shielding** | Magnetically Shielded | | **Dimensions** | 7.6mm x 7.6mm x 3.55mm | --- ### 2. Core Components and Materials The construction of the DR73 series involves several specific electronic materials to ensure performance: * **Ferrite Drum Core:** Provides high permeability while maintaining low core losses at high frequencies. * **Magnet Wire:** High-temperature copper wire wound around the drum core. * **Magnetic Shielding:** A ferrite sleeve surrounds the winding, which serves two purposes: 1. It concentrates the magnetic flux, increasing inductance. 2. It minimizes EMI (Electromagnetic Interference) radiation, protecting nearby sensitive components. * **Solder Pads:** Matte tin-plated over copper for excellent solderability on PCBs. --- ### 3. Common Applications Because of its high current capability and compact size, this inductor is commonly found in: 1. **DC-DC Converters:** Used as an energy storage element in Buck, Boost, and SEPIC converters. 2. **Voltage Regulator Modules (VRMs):** Found in computer motherboards and servers. 3. **Battery Powered Devices:** Ideal for handheld electronics where space is limited and efficiency is critical. 4. **LED Drivers:** Used to smooth current ripple in lighting applications. --- ### 4. Part Number Breakdown Understanding the nomenclature helps in identifying variants: * **DR:** Series Name (Drum Core, Shielded). * **73:** Size code (Approx. 7mm x 7mm footprint, 3mm height). * **3R3:** Inductance value (3.3 microhenries; "R" acts as the decimal point). * **-R:** RoHS compliant / Lead-free. ---