The **FP3-150-R** is a high-frequency, high-current power inductor part of the **FP3 series** manufactured by Eaton (formerly Cooper Bussmann/Coiltronics). These are primarily used in high-density power conversion applications. --- ## 1. Technical Specifications The "150" in the part number indicates an inductance of **0.150 µH**. Below is a breakdown of its key electronic characteristics: | Parameter | Value / Specification | | :--- | :--- | | **Inductance (L)** | 150 nH (0.150 µH) | | **Rated Current ($I_{rms}$)** | ~35 - 42 Amperes (depending on temp rise) | | **Saturation Current ($I_{sat}$)** | ~50 - 65 Amperes | | **DC Resistance (DCR)** | Extremely Low (approx. 0.50 - 0.70 mΩ) | | **Operating Temperature** | -40°C to +125°C | | **Package Type** | Surface Mount (SMD) | --- ## 2. Core Material and Construction The FP3 series utilizes **Ferrite core material**. This is critical for its electronic performance: * **Low Core Loss:** Ferrite is designed to handle high switching frequencies (up to 2 MHz) with minimal energy dissipation as heat. * **Vertical Winding:** The "R" usually denotes a specific RoHS-compliant flat-wire construction. The flat wire maximizes the surface area, reducing the **Skin Effect** at high frequencies and lowering the DC Resistance (DCR). --- ## 3. Electronic Behavior and Application Because of its very low inductance and extremely high current handling, the FP3-150-R behaves as follows in a circuit: ### A. Voltage Regulator Modules (VRMs) It is most commonly found in multi-phase buck converters that power CPUs and GPUs. In these circuits: 1. It stores energy during the "on" cycle of a MOSFET. 2. It smooths the output current to provide a steady voltage to sensitive silicon components. ### B. High Saturation Characteristics The "Saturation Current" ($I_{sat}$) is the point where the inductance drops by a specific percentage (usually 20% or 30%). The FP3-150-R is designed for a **soft saturation** curve, meaning it doesn't lose its inductive properties instantly when a current spike occurs, protecting the power stage. ### C. Thermal Management Due to the low DCR, this part generates very little heat from resistive losses ($I^2R$). However, at 40A+, even 0.6 mΩ produces measurable heat, so it is designed to be soldered to large copper planes on a PCB to act as a heat sink. --- ## 4. Part Number Decoder | Code | Meaning | | :--- | :--- | | **FP** | Flat-Pac Series (High current, low profile) | | **3** | Size/Physical Dimensions (Approx. 7.2 x 6.7 x 3.0 mm) | | **150** | Inductance value in nanohenries (150nH) | | **-R** | RoHS Compliant / Lead-Free |