The **CMS1-1-R** is a specific electronic component belonging to the **Common Mode Choke** family, manufactured by Eaton (formerly Coiltronics/Bussmann). It is primarily used for EMI (Electromagnetic Interference) filtering in power and signal lines. --- ### 1. Key Technical Specifications The following table summarizes the primary electrical and physical characteristics of the CMS1-1-R: | Feature | Specification | | :--- | :--- | | **Inductance** | 212 µH (Typical) | | **Current Rating (Irms)** | 1.1 Amps | | **DCR (Direct Current Resistance)** | 0.160 Ohms (Max) | | **Mounting Type** | Surface Mount (SMD) | | **Package / Case** | CMS Series (Size 1) | | **Operating Temperature** | -40°C to +125°C | | **Termination Style** | Gullwing (Lead-free, RoHS compliant) | --- ### 2. Functional Overview Common mode chokes like the CMS1-1-R are used to suppress high-frequency noise that is common to two or more data or power lines. * **Common Mode Filtering:** It allows the desired "differential" signal to pass through while providing high impedance to "common-mode" noise (noise traveling in the same direction on both lines). * **Magnetic Core:** Utilizes a ferrite core material characterized by high permeability, which is effective at attenuating noise in the MHz range. * **Winding Configuration:** It consists of two identical coils wound on a single core. The "1-1" in the part number often refers to the 1:1 turns ratio. --- ### 3. Common Applications The CMS1-1-R is typically found in the following electronic circuits: 1. **Switch Mode Power Supplies (SMPS):** To filter out switching noise before it exits the device or enters the power grid. 2. **DC-DC Converters:** Reducing ripple and noise on input/output lines. 3. **Data Lines:** Protecting sensitive communication interfaces (like USB or CAN bus) from EMI. 4. **Industrial Electronics:** Providing noise immunity in harsh electrical environments. --- ### 4. PCB Footprint & Mechanicals The "R" suffix indicates that the part is **RoHS compliant**. The physical dimensions are compact, making it suitable for high-density PCB layouts. ```text CMS1 Series Approximate Dimensions: Length: 9.4 mm Width: 7.0 mm Height: 4.8 mm ``` ---