The **XFHCL4M-R18M** is a high-performance, shielded fixed inductor primarily used in power management circuits. It is part of the XFHCL series, known for its low profile and high current handling capabilities. --- ### 1. Key Technical Specifications The following table highlights the primary electrical characteristics of the XFHCL4M-R18M: | Parameter | Specification | | :--- | :--- | | **Inductance** | 0.18 µH | | **Tolerance** | ±20% (M) | | **DC Resistance (DCR)** | ~1.1 mΩ (Typ) / 1.3 mΩ (Max) | | **Saturation Current (Isat)** | ~30A - 35A | | **Temperature Rise Current (Irms)** | ~22A - 25A | | **Operating Temperature** | -40°C to +125°C | | **Package Size** | 4.0 x 4.0 mm (approx.) | --- ### 2. Core Components and Construction * **Magnetic Core:** Utilizes a metal alloy powder core. Unlike traditional ferrite cores, metal powder offers a "soft saturation" characteristic, meaning the inductance drops gradually rather than abruptly as current increases. * **Shielding:** It is a **magnetically shielded** construction. This minimizes Electromagnetic Interference (EMI) and prevents the magnetic field from affecting neighboring components on a dense PCB. * **Terminations:** Features lead-free (RoHS compliant) solder pads designed for surface mount technology (SMT) reflow soldering. --- ### 3. Application Use Cases Because of its very low inductance (0.18 µH) and high saturation current, this part is ideal for high-frequency switching environments: 1. **DC-DC Converters:** Used in Step-down (Buck) converters for CPUs, GPUs, and FPGAs where low voltage and high current are required. 2. **Voltage Regulator Modules (VRM):** Common in laptops, servers, and high-end workstations. 3. **Mobile Devices:** Its low profile makes it suitable for slim smartphones and tablets. 4. **Battery Powered Systems:** High efficiency due to extremely low DC Resistance (DCR). --- ### 4. Part Number Breakdown While naming conventions vary slightly by manufacturer, the code generally breaks down as follows: | Segment | Meaning | | :--- | :--- | | **XFHCL** | Series Name (Metal Alloy Shielded Inductor) | | **4M** | Physical size code (approx. 4.0mm footprint) | | **R18** | Inductance value (R represents the decimal: 0.18 µH) | | **M** | Tolerance code (M = ±20%) |