## Detailed Overview: DR1040-470-R Inductor The **DR1040-470-R** is a specific model of a surface-mount (SMD) power inductor manufactured by **Eaton (formerly Coiltronics)**. It belongs to the DR Series, which is known for its high power density and shielded construction. --- ### 1. Key Technical Specifications The part number itself contains encoded information about its performance characteristics. | Parameter | Specification | | :--- | :--- | | **Inductance** | 47 $\mu$H | | **Tolerance** | ±20% | | **DC Resistance (DCR)** | 0.155 $\Omega$ (Max) | | **RMS Current ($I_{rms}$)** | 1.54 Amps | | **Saturation Current ($I_{sat}$)** | 1.83 Amps | | **Operating Temperature** | -40°C to +125°C | | **Shielding** | Magnetically Shielded | --- ### 2. Physical Dimensions The "1040" in the part number refers to the physical footprint of the component. * **Width/Length:** ~10.3 mm x 10.5 mm * **Height:** 4.0 mm (Max) * **Packaging:** Available in Tape and Reel for automated assembly. --- ### 3. Electronic Characteristics & Functionality #### A. Magnetic Shielding The "DR" series features a ferrite drum core with a ring core (shield). This construction minimizes **Electromagnetic Interference (EMI)**, ensuring that the magnetic field stays contained within the component. This is critical for high-density PCB layouts where components are placed close together. #### B. Saturation Current ($I_{sat}$) vs. RMS Current ($I_{rms}$) * **$I_{sat}$ (1.83A):** This is the point where the inductance drops by a specified percentage (usually 30%). Beyond this current, the inductor loses its ability to store energy efficiently. * **$I_{rms}$ (1.54A):** This represents the continuous DC current that will cause the component temperature to rise by 40°C. #### C. Core Material It utilizes a **Ferrite core**, which provides low core losses at high frequencies, making it ideal for efficient power conversion. --- ### 4. Common Applications The DR1040-470-R is typically found in power management circuits, including: 1. **DC-DC Converters:** Buck (step-down), Boost (step-up), and SEPIC topologies. 2. **Voltage Regulator Modules (VRMs):** Providing stable power to CPUs or FPGAs. 3. **Battery Powered Equipment:** Used in laptops and handheld devices due to its low profile. 4. **Filters:** Used in output stages to smooth out current ripples. --- ### 5. Part Number Breakdown `DR` `10` `40` `-` `470` `-` `R` * **DR:** Product Series (Drum Core, Shielded). * **10:** Approx. 10mm width. * **40:** Approx. 4mm height. * **470:** Inductance code ($47 \times 10^0$ = 47 $\mu$H). * **R:** RoHS compliant.