The **CTX20-3A-R** is a high-performance, surface-mount power inductor from the **OCTA-PAC® PLUS** series, manufactured by Eaton (formerly Cooper Bussmann/Coiltronics). These components are unique because they feature **dual windings**, allowing them to be configured in multiple ways for DC-DC converters and filtering applications. --- ### 1. Key Technical Specifications The performance of the CTX20-3A-R depends on whether the two internal windings are connected in series or in parallel. | Characteristic | Parallel Connection | Series Connection | | :--- | :--- | :--- | | **Inductance ($L$)** | 20.2 $\mu$H | 80.8 $\mu$H | | **Rated Current ($I_{rms}$)** | 2.51 A | 1.25 A | | **Peak Current ($I_{sat}$)** | 3.52 A | 1.76 A | | **DCR (DC Resistance)** | 0.057 $\Omega$ | 0.228 $\Omega$ | ### 2. Physical and Material Properties * **Core Material:** Powered Iron (optimized for high-frequency power applications). * **Package Type:** Surface Mount (SMT). * **Dimensions:** Approximately 11.4mm x 11.4mm x 6.0mm. * **Operating Temperature:** -40°C to +125°C. * **RoHS Compliant:** Yes (indicated by the "-R" suffix). --- ### 3. Functional Applications Because of the dual-winding design, the CTX20-3A-R is highly versatile: 1. **Inductor Mode:** Used for ripple filtering in power supplies. 2. **1:1 Transformer Mode:** Can be used for isolation or in SEPIC (Single-Ended Primary-Inductor Converter) topologies. 3. **Common Mode Choke:** Used to suppress electromagnetic interference (EMI) on power lines. 4. **Voltage Step-up/Step-down:** The windings can be wired to act as a basic autotransformer. --- ### 4. Part Number Breakdown * **CTX:** Series designation (Coiltronics). * **20:** Base inductance value code. * **3A:** Size/Power rating code (Size 3, "A" refers to the high-power PLUS version). * **R:** RoHS compliant. ---