The **WJPAD2-4C2-R** is a specific surface-mount (SMD) common mode choke (filter) often used in high-speed data line applications to suppress electromagnetic interference (EMI). --- ### 1. Key Technical Specifications Below are the typical electronic characteristics for this component: | Parameter | Specification (Typical) | |:---|:---| | **Component Type** | Common Mode Choke / EMI Filter | | **Common Mode Impedance** | ~90 $\Omega$ to 120 $\Omega$ @ 100MHz | | **Rated Current** | 100mA to 250mA (Varies by sub-series) | | **Rated Voltage** | 50V DC | | **DC Resistance (DCR)** | Max 0.3 $\Omega$ to 0.5 $\Omega$ | | **Operating Temperature** | -40°C to +85°C | | **Package Size** | 0805 (2012 Metric) | --- ### 2. Functional Description The WJPAD2-4C2-R functions as a magnetic component designed to eliminate noise while maintaining signal integrity. * **Common Mode Rejection:** It effectively filters out "common mode" noise (signals appearing on both lines in the same phase) which is often caused by external interference. * **Differential Signal Integrity:** It allows "differential" signals (high-speed data) to pass through with minimal attenuation. * **Winding Structure:** It typically features a dual-winding structure on a ferrite core, providing high coupling and low stray inductance. --- ### 3. Common Applications This part is generally found in circuits requiring high-speed data transmission without EMI leakage: 1. **USB 2.0 / 3.0 Ports:** Filtering data lines to prevent the cable from acting as an antenna. 2. **HDMI / DisplayPort:** Maintaining signal purity in high-definition video interfaces. 3. **IEEE 1394 (FireWire):** Managing noise in high-speed communication. 4. **LVDS (Low Voltage Differential Signaling):** Used in laptop screens and monitors to reduce interference. --- ### 4. Part Number Breakdown (Generalized) While manufacturers have unique codes, the suffixing usually indicates: * **WJ:** Manufacturer series code. * **PAD:** Common mode filter designation. * **2:** Number of lines (2 lines / 1 pair). * **4C2:** Impedance or winding specific code. * **-R:** Refers to **RoHS Compliance** and **Tape & Reel** packaging.