The **CT0805HT-R39K** is a high-temperature, surface-mount (SMD) wire-wound chip inductor. It is designed for high-frequency applications where stability and reliability under heat are critical. --- ### 1. Technical Specifications | Parameter | Value | | :--- | :--- | | **Inductance** | 0.39 µH (390 nH) | | **Tolerance** | ±10% (Indicated by 'K') | | **Case Size** | 0805 (2.0mm x 1.25mm) | | **DC Resistance (DCR)** | Max 0.85 Ω | | **Rated Current (Idc)** | ~400 mA | | **Self-Resonant Frequency (SRF)** | Min 600 MHz | | **Operating Temperature** | -40°C to +150°C (HT Series) | --- ### 2. Part Number Breakdown Understanding the nomenclature helps identify the component's characteristics: * **CT**: Series prefix (Ceramic core/Wire-wound). * **0805**: Physical dimensions (0.08 x 0.05 inches). * **HT**: **High Temperature** rating (capable of withstanding up to 150°C). * **R39**: Inductance value ($R$ acts as a decimal point; $0.39$ µH). * **K**: Tolerance code (K = ±10%). --- ### 3. Key Features and Construction * **Wire-Wound Construction:** Unlike multilayer inductors, wire-wound versions offer much higher **Q-factors** (quality factor) and lower DC resistance, making them more efficient for RF signals. * **Ceramic Core:** Provides excellent thermal stability and high-frequency performance. * **High Temperature (HT) Capability:** Standard inductors often fail or drift at 125°C. This part is rated for 150°C, making it suitable for "under-the-hood" automotive or industrial applications. * **Encapsulation:** Usually coated with a clear epoxy or resin to protect the fine copper wire from mechanical stress and environmental moisture. --- ### 4. Common Applications 1. **Automotive Electronics:** Sensors and control units located near the engine or exhaust systems. 2. **RF Communication:** Impedance matching and filtering in high-frequency circuits. 3. **Broadband Filtering:** Used in power supply lines to suppress high-frequency noise while allowing DC current to pass. 4. **Industrial IoT:** Devices deployed in harsh environments where ambient temperatures are elevated.