### Overview of CMS2-13-R The **CMS2-13-R** is a high-performance, surface-mount (SMD) Common Mode Choke manufactured by **Eaton (formerly Cooper Bussmann/Coiltronics)**. It is part of the CMS series, designed to provide effective noise suppression in power electronics. --- ### 1. Key Specifications The following table highlights the primary electrical and physical characteristics: | Feature | Specification | | :--- | :--- | | **Inductance** | 12.8 µH (Typical) | | **Current Rating (Irms)** | 6.8 Amps | | **DCR (Direct Current Resistance)** | 10.3 mΩ (Max) | | **Number of Windings** | 2 | | **Mounting Type** | Surface Mount (SMD) | | **Operating Temperature** | -40°C to +125°C | | **Package Size** | Size 2 (approx. 11.4mm x 8.9mm) | --- ### 2. Functional Electronic Components The CMS2-13-R is not a single "part" but an assembly of specific electronic elements: #### A. Ferrite Core The device uses a high-frequency ferrite core. Ferrite is chosen for its high magnetic permeability and low electrical conductivity, which helps prevent eddy current losses while concentrating the magnetic field to suppress electromagnetic interference (EMI). #### B. Bifilar/Dual Winding It consists of two separate coils wound on the same core. * **Common Mode Rejection:** When signals flow in the same direction (noise), the magnetic fields add up, creating high impedance that blocks the noise. * **Differential Mode Transparency:** When signals flow in opposite directions (desired current), the magnetic fields cancel out, allowing the current to pass with minimal resistance. #### C. Solder Pad Terminations The "R" in the part number usually denotes **RoHS compliance**. The terminations are finished with matte tin over copper, ensuring reliable solder joints during the reflow process. --- ### 3. Applications Because of its high current capacity and compact SMD design, it is frequently used in: * **Switch Mode Power Supplies (SMPS):** Filtering input/output noise. * **DC-DC Converters:** Reducing ripple current. * **Industrial Electronics:** Protecting sensitive circuits from power line interference. * **Telecommunications:** Signal line filtering. --- ### 4. Part Number Breakdown Understanding the nomenclature helps in identifying variants: * **CMS:** Series Name (Common Mode Suppression). * **2:** Core/Package Size. * **13:** Inductance code (12.8 µH rounded). * **R:** RoHS Compliant.