The **CDB78D73BNP-R27MC** is a high-current, surface-mount (SMD) power inductor manufactured by **Sumida**. It belongs to the CDB series, which is characterized by its high efficiency and magnetic shielding. --- ## 1. Technical Specifications Below are the primary electrical and physical characteristics of the component: | Parameter | Specification | | :--- | :--- | | **Inductance** | 0.27 µH | | **Tolerance** | ±20% (M) | | **Saturation Current (Isat)** | ~40.0 Amperes | | **Temperature Rise Current (Irms)** | ~28.0 Amperes | | **DC Resistance (DCR)** | 0.73 mΩ (Max) | | **Dimensions (L x W x H)** | 7.5 x 7.3 x 7.3 mm | | **Core Material** | Ferrite | | **Operating Temperature** | -40°C to +125°C | --- ## 2. Key Internal Features * **Magnetic Shielding:** The part features a closed magnetic circuit, which minimizes Electromagnetic Interference (EMI) and prevents the inductor from affecting nearby sensitive components on the PCB. * **Flat Wire Technology:** It typically utilizes flat copper wire windings. This reduces skin effect losses and allows for a lower DCR (Direct Current Resistance), which improves efficiency at high frequencies. * **High Current Capability:** Due to its low DCR and ferrite core, it can handle very high saturation currents relative to its small footprint. --- ## 3. Common Applications This inductor is specifically designed for high-density power applications where space is limited but current requirements are high. * **Multi-phase VRMs:** Used in Voltage Regulator Modules for CPUs and GPUs in servers and high-end desktops. * **DC/DC Converters:** Point-of-Load (POL) converters where high efficiency is required. * **Industrial Equipment:** Power supplies for robotics and automation controllers. * **Networking:** Power stages for routers and high-speed switches. --- ## 4. Part Number Breakdown Understanding the Sumida nomenclature helps in identifying variants: 1. **CDB:** Series name (High Current Power Inductor). 2. **78D73:** Physical size/case dimensions. 3. **BNP:** Packaging and assembly style. 4. **R27:** Inductance value ($R27 = 0.27$ µH). 5. **M:** Tolerance ($\pm 20\%$). 6. **C:** Specific manufacturer code or revision.