The **FL201209-R56K** is a surface-mount (SMD) multilayer ferrite chip inductor, commonly used for high-frequency filtering and signal conditioning in electronic circuits. --- ### 1. Part Number Breakdown Understanding the nomenclature helps identify the physical and electrical characteristics of the component: | Segment | Meaning | Description | | :--- | :--- | :--- | | **FL** | Series Code | Multilayer Ferrite Inductor (General Purpose) | | **201209** | Size (Metric) | 2.0mm x 1.2mm x 0.9mm (corresponds to **0805** imperial) | | **R56** | Inductance Value | R56 = **0.56 µH** (microhenries) | | **K** | Tolerance | **±10%** | --- ### 2. Key Specifications While specific data can vary slightly by manufacturer (such as TDK, Murata, or Taiyo Yuden), the standard specifications for a R56K 0805 inductor are typically: * **Inductance:** 0.56 µH * **Tolerance:** ±10% * **DC Resistance (DCR):** Usually ranges between 0.30Ω to 0.55Ω. * **Rated Current:** Typically between 150mA and 300mA. * **Self-Resonant Frequency (SRF):** Generally > 100 MHz. * **Operating Temperature:** -40°C to +85°C (standard) or up to +125°C. --- ### 3. Construction and Materials The "FL" series uses a **Multilayer Technology** which differentiates it from wire-wound inductors: * **Core Material:** Ferrite. This provides high magnetic permeability and effectively suppresses electromagnetic interference (EMI). * **Internal Electrode:** Usually Silver (Ag) printed in layers to form the coil structure. * **Termination:** Nickel (Ni) barrier with a Tin (Sn) plating to ensure good solderability and prevent silver migration. --- ### 4. Common Applications Due to its small footprint (0805) and ferrite properties, this part is ideal for: 1. **EMI Suppression:** Filtering high-frequency noise in digital I/O lines. 2. **Power Supply Decoupling:** Preventing noise from entering or leaving sensitive DC-DC converter stages. 3. **Signal Conditioning:** Used in resonance circuits or as a low-pass filter in mobile phones, computers, and consumer electronics. --- ### 5. Equivalent Replacement Guide If sourcing this specific part is difficult, look for inductors with these matching parameters: ```json { "Package": "0805 (2012 Metric)", "Inductance": "0.56uH", "Tolerance": "10% or tighter (e.g., J/5%)", "Type": "Multilayer Ferrite" } ```