### Technical Overview: UP3B-3R3-R Power Inductor The **UP3B-3R3-R** is a high-performance, shielded power inductor manufactured by **Eaton (formerly Coiltronics/Bussmann)**. It belongs to the Uni-Pac™ (UP) series, designed specifically for surface-mount (SMD) applications requiring high power density and reliability. --- ### 1. Key Technical Specifications | Parameter | Value | | :--- | :--- | | **Inductance** | 3.3 µH | | **Tolerance** | ±20% | | **Current Rating (Irms)** | 6.1 Amps | | **Saturation Current (Isat)** | 8.0 Amps | | **DC Resistance (DCR)** | 0.0121 Ω (Max) | | **Package / Case** | SMD (13.9mm x 9.4mm x 6.8mm) | | **Operating Temperature** | -40°C to +125°C | | **Shielding** | Magnetically Shielded | --- ### 2. Physical and Material Characteristics * **Shielding:** The inductor is **magnetically shielded**, which minimizes Electromagnetic Interference (EMI). This makes it suitable for use near sensitive components on a PCB. * **Construction:** It features a robust drum core design with a ferrite sleeve. The "R" suffix in the part number indicates that the component is **RoHS compliant**. * **Mounting:** Designed for Surface Mount Device (SMD) technology, featuring high-strength solder pads for mechanical stability during thermal cycling. --- ### 3. Functional Applications The UP3B-3R3-R is primarily used in power management circuits where high current handling and low losses are critical: 1. **DC-DC Converters:** Acts as an energy storage element in Buck, Boost, and SEPIC converters. 2. **Voltage Regulator Modules (VRMs):** Used in computers and servers to step down voltage for CPUs and GPUs. 3. **Industrial Electronics:** Ideal for motor drives, battery-powered equipment, and telecommunications infrastructure. 4. **Filtering:** Utilized in LC filters to smooth out ripple current in high-frequency switching power supplies. --- ### 4. Performance Considerations * **Saturation Current ($I_{sat}$):** This is the current level at which the inductance drops by a specific percentage (usually 30%). For this part, exceeding 8.0A will cause the inductor to lose its effectiveness. * **Thermal Management ($I_{rms}$):** The 6.1A rating is based on the temperature rise (usually 40°C) above ambient. Designing for proper airflow or PCB heat-sinking is recommended if running at maximum current. ---