The **CTX33-3-R** is a high-performance, surface-mount (SMT) power inductor/transformer belonging to the **OCTA-PAC** series, manufactured by Eaton (formerly Cooper Bussmann/Coiltronics). ### 1. Technical Specifications The CTX33-3-R is characterized by its "dual-winding" design, which allows it to be used in various circuit configurations. | Parameter | Specification | | :--- | :--- | | **Inductance (Parallel)** | 32.2 µH | | **Inductance (Series)** | 128.8 µH | | **DC Resistance (DCR)** | 0.165 Ω (Parallel) / 0.660 Ω (Series) | | **Current Rating (Isat)** | ~1.60 A (Parallel) | | **Mounting Type** | Surface Mount (SMT) | | **Dimensions** | Approx. 11.43mm x 11.43mm | | **RoHS Compliant** | Yes (indicated by the "-R" suffix) | --- ### 2. Core Functional Features * **Dual Winding Versatility:** It contains two identical windings. Depending on how you connect the pins, it can act as: * **Single Inductor:** High current (Parallel) or High Inductance (Series). * **1:1 Transformer:** For isolation or voltage transformation. * **Common Mode Choke:** For EMI filtering. * **Toroidal Core:** Uses a powdered iron toroidal core, which offers low magnetic radiation (self-shielding) and high efficiency. * **Construction:** The "33" in the part number refers to the specific core size/type, and the "-3" refers to the performance range/inductance value within that size. --- ### 3. Common Applications The CTX33-3-R is widely used in power management circuits where space and efficiency are critical: 1. **DC-DC Converters:** Used in Buck, Boost, and SEPIC topologies. 2. **EMI Filtering:** Acting as a common mode choke to reduce noise in power lines. 3. **Isolation:** Providing electrical isolation between two circuits in low-power signal or power transfer. 4. **Energy Storage:** Storing energy in switching power supplies. --- ### 4. Connection Diagram Example Because it is a dual-winding component, the pinout determines the behavior: ```text Parallel Connection (High Current) Series Connection (High Inductance) 1 o-------+-------o 3 1 o-------o 3 | | L L | | 2 o-------+-------o 4 2 o-------o 4 (Connect 2 to 3) ```