The **1812SMS-R15GLC** is a high-performance Surface Mount Device (SMD) inductor, specifically a square-core air core inductor manufactured by **Coilcraft**. These components are designed for high-frequency applications where high Q-factors and tight tolerances are required. --- ### 1. Key Technical Specifications | Parameter | Value / Description | | :--- | :--- | | **Manufacturer** | Coilcraft | | **Series** | 1812SMS (Surface Mount Spring) | | **Inductance** | 0.15 µH (150 nH) | | **Tolerance** | ±2% (indicated by 'G') | | **Case Size** | 1812 (4.57 x 3.81 x 3.30 mm) | | **Quality Factor (Q)** | 100 (at 150 MHz) | | **SRF (Self Resonant Freq)** | 1.15 GHz | | **DCR (DC Resistance)** | 0.16 Ohms (Max) | | **Current Rating (Irms)** | 2.5 Amps | --- ### 2. Part Number Breakdown Understanding the nomenclature helps in identifying variants within the same family: * **1812**: Represents the physical dimensions (approx. 0.18 x 0.12 inches). * **SMS**: Surface Mount Spring (Air Core construction). * **R15**: The inductance value. "R" acts as a decimal point (0.15 µH). * **G**: Tolerance code (G = ±2%, J = ±5%). * **L**: Termination style (L = RoHS compliant Silver-Palladium-Platinum-Glass frit). * **C**: Packaging code (C = 7" machine-ready reel). --- ### 3. Physical Construction & Features * **Air Core Inductor:** Unlike ferrite core inductors, air cores have no magnetic core. This ensures **zero core loss** and no saturation, making them exceptionally stable across different currents and frequencies. * **Flat Top:** The component features a high-temperature polyimide film "cap" on top, which provides a flat surface for automated pick-and-place machinery. * **High Q-Factor:** Because there is no core to dissipate energy, these inductors offer very low losses at high frequencies, essential for RF tuning. --- ### 4. Common Applications The 1812SMS series is typically found in RF and high-frequency circuitry: 1. **Impedance Matching:** Used in power amplifiers to match the output stage to the antenna. 2. **Filter Networks:** Ideal for bandpass or low-pass filters in wireless communication devices. 3. **Frequency Tuning:** Used in Voltage Controlled Oscillators (VCOs) and RF synthesizers. 4. **MRI Equipment:** Often used in medical imaging due to the absence of magnetic materials (non-magnetic versions available). ---