The **CMS1-13-R** is a specific surface-mount (SMD) common mode choke manufactured by **Eaton (formerly Coiltronics)**. It is part of the CMS series, designed primarily for power line noise filtering and signal transformation. --- ### 1. Technical Specifications Below are the key electrical and physical characteristics of the CMS1-13-R: | Parameter | Specification | | :--- | :--- | | **Inductance** | 13.5 µH (Typical) | | **Current Rating (Irms)** | 3.5 Amps | | **DCR (Direct Current Resistance)** | 22.0 mΩ (Maximum) | | **Mounting Type** | Surface Mount (SMD) | | **Operating Temperature** | -40°C to +125°C | | **Core Material** | Ferrite | | **Dimensions** | ~9.4 mm x 7.0 mm x 5.0 mm | --- ### 2. Key Features * **Common Mode Noise Suppression:** Specifically engineered to reduce electromagnetic interference (EMI) that travels in the same direction on both power/signal lines. * **High Current Capability:** Despite its small footprint, it can handle up to 3.5A, making it suitable for power supplies. * **Dual Winding Construction:** It features two identical windings on a single core. This allows it to be used as: 1. A common mode choke (to filter noise). 2. A 1:1 transformer (for isolation or voltage level shifting). 3. An inductor (by connecting windings in series or parallel). --- ### 3. Common Applications The CMS1-13-R is typically found in the following electronic environments: 1. **DC-DC Converters:** Used as an input or output filter to comply with EMC regulations. 2. **Switching Power Supplies:** To suppress high-frequency noise generated by the switching transistors. 3. **Data Lines:** Protecting sensitive communication lines from external electrical noise. 4. **Signal Isolation:** Utilizing the 1:1 turns ratio to isolate different stages of a circuit. --- ### 4. Part Number Breakdown Understanding the Eaton/Coiltronics naming convention: * **CMS**: Series Name (Common Mode Surface Mount). * **1**: Size/Package dimension code. * **13**: Inductance value code (representing ~13 µH). * **R**: RoHS Compliant (Lead-free). ---