The **CTX1-4A-R** is a specific electronic component belonging to the **OCTA-PAC® PLUS** series, manufactured by Eaton (formerly Bussmann/Coiltronics). It is a high-power density, surface-mount toroidal transformer/inductor. --- ### 1. General Specifications The CTX1-4A-R is designed for versatility, featuring two identical windings that can be connected in series or parallel. | Parameter | Value / Specification | | :--- | :--- | | **Inductance (Parallel)** | 1.05 µH | | **Inductance (Series)** | 4.21 µH | | **Current Rating (Parallel)** | 12.3 Amps | | **Current Rating (Series)** | 6.15 Amps | | **DCR (Direct Current Resistance)** | Low resistance for high efficiency | | **Mounting Type** | Surface Mount (SMD) | | **Core Material** | Powdered Iron (High frequency/Low loss) | --- ### 2. Physical Characteristics The "4A" in the part number refers to the specific package size within the OCTA-PAC series. * **Geometry:** Toroidal (doughnut-shaped). This shape is excellent for EMI (Electromagnetic Interference) shielding because the magnetic field is contained within the core. * **Termination:** Lead-free, RoHS compliant (indicated by the **-R** suffix). * **Footprint:** Typically used in space-constrained PCB designs requiring high power output. --- ### 3. Key Applications Because of its dual-winding nature, the CTX1-4A-R is commonly used in: 1. **DC-DC Converters:** Used as a power inductor in buck, boost, or forward converters. 2. **Transformers:** Can act as a 1:1 isolation transformer or a flyback transformer. 3. **Common-Mode Choke:** When wired correctly, it filters out noise in power lines. 4. **SEPIC Topology:** Frequently used in Single-Ended Primary-Inductor Converters due to the integrated dual-coil design. --- ### 4. Connection Configurations The component features four pins. How you solder them determines its behavior: | Configuration | Connection Method | Effect | | :--- | :--- | :--- | | **Parallel** | Pins 1-4 and 2-3 tied together | High current capacity, lower inductance. | | **Series** | Pin 2 connected to Pin 3 | Higher inductance, lower current capacity. | | **Transformer** | Input on 1-2, Output on 4-3 | Provides 1:1 voltage ratio/isolation. | ---