The part number **0402CS-R12XJEQ** refers to a high-frequency wire-wound chip inductor manufactured by **Coilcraft**. This specific component is part of the 0402CS series, which is widely used in RF (Radio Frequency) and wireless communication circuits. --- ### 1. Part Number Breakdown To understand the specifications, we can decode the part number: | Segment | Code | Description | | :--- | :--- | :--- | | **Size/Series** | 0402CS | 0402 (1.0 x 0.5 mm) Ceramic Series Inductor | | **Inductance** | R12 | 120 nH (R denotes decimal point, value in $\mu H$) | | **Tolerance** | J | ±5% | | **Termination** | E | Silver-palladium-platinum-glass frit | | **Packaging** | Q | 7″ machine-ready plastic tape (approx. 2000 per reel) | --- ### 2. Technical Specifications These components are designed for high-performance RF applications where high Q-factors and stable inductance are required. | Parameter | Value | | :--- | :--- | | **Inductance** | 120 nH | | **Tolerance** | ±5% | | **Quality Factor (Q min)** | 32 at 250 MHz | | **Self-Resonant Frequency (SRF)** | 1.30 GHz (Typical) | | **DCR (Direct Current Resistance)** | 1.90 Ohms (Max) | | **IDC (Rated Current)** | 170 mA | | **Operating Temperature** | -40°C to +125°C | --- ### 3. Key Features * **Wire-Wound Construction:** Unlike multilayer inductors, the wire-wound design provides significantly higher Q-factors and higher current handling capabilities. * **Miniature Footprint:** The 0402 (1005 metric) size is ideal for high-density PCB layouts in mobile devices. * **Ceramic Core:** Provides excellent thermal stability and very low loss at high frequencies. ### 4. Common Applications * **RF Impedance Matching:** Used in the front-end of cellular phones and Wi-Fi modules to match antenna impedance. * **Filter Circuits:** High-pass, low-pass, and band-pass filters for signal processing. * **Oscillators:** Frequency stabilization in VCOs (Voltage Controlled Oscillators). --- ### 5. Land Pattern Example (0402) ```text [ 0.66 mm ] <------> +---+ +---+ | | | | [ 0.46 mm ] +---+ +---+ <------> [ 0.36 mm ] Gap ```