### Overview of CTX10-4P-R The **CTX10-4P-R** is a high-performance, surface-mount (SMD) power inductor/transformer belonging to the **OCTA-PAC®** series manufactured by Eaton (formerly Cooper Bussmann/Coiltronics). It is unique because it features **dual windings**, allowing it to be configured as a single inductor, two coupled inductors, or a 1:1 transformer. --- ### Key Specifications | Parameter | Value / Range | | :--- | :--- | | **Inductance (Parallel)** | 10.3 $\mu$H | | **Inductance (Series)** | 41.2 $\mu$H | | **Current Rating (Isat)** | ~4.7 A (Parallel) | | **DC Resistance (DCR)** | 0.033 $\Omega$ (Parallel max) | | **Operating Temperature** | -40°C to +125°C | | **Package Size** | OCTA-PAC® Size 4 | | **Termination Style** | Gull-wing (SMD) | --- ### Internal Structure and Configuration The "4P" in the part number indicates the size and power level. The device consists of two separate copper windings on a single toroidal ferrite core. This provides four connection pins, allowing for three main circuit applications: 1. **Parallel Mode:** Connect pins 1-4 and 2-3. This provides maximum current capacity and minimum inductance (10.3 $\mu$H). 2. **Series Mode:** Connect pins 2-3 and use 1-4 as terminals. This quadruples the inductance (41.2 $\mu$H) but halves the current rating. 3. **1:1 Transformer Mode:** Use one winding as the primary and the other as the secondary. This is ideal for isolation or SEPIC converters. --- ### Common Applications Due to its versatile design and low EMI (Electromagnetic Interference) signature of the toroidal core, the CTX10-4P-R is commonly used in: * **DC-DC Converters:** Buck, Boost, and Forward converters. * **SEPIC Topology:** Used as a coupled inductor to save board space. * **Common Mode Chokes:** For filtering noise in power lines. * **Battery Powered Equipment:** Where high efficiency and small footprint are required. --- ### Mechanical Dimensions * **Length:** ~15.0 mm * **Width:** ~12.7 mm * **Height:** ~6.35 mm