The **ST1280C..K** series refers to high-power, hockey-puck style **Phase Control Thyristors (SCRs)** manufactured by Vishay (formerly International Rectifier). These devices are designed for heavy-duty industrial applications requiring high current and voltage regulation. --- ## 1. Key Technical Specifications The "1280C" indicates the average current rating, while the "K" denotes the package type (A-24 / K-PUK). | Parameter | Typical Value | | :--- | :--- | | **IT(AV)** (Max Average On-state Current) | ~1280 A @ $T_c = 55^\circ C$ | | **IT(RMS)** (Max RMS On-state Current) | ~2380 A | | **VDRM / VRRM** (Repetitive Peak Voltage) | 400V to 1600V (depending on sub-model) | | **ITSM** (Non-repetitive Surge Current) | ~22,000 A (at 50Hz) | | **Package Style** | K-PUK (Press-pack / Hockey-puck) | --- ## 2. Structural and Functional Components ### A. The Semiconductor Die * **Material:** High-purity Silicon. * **Structure:** P-N-P-N four-layer device. * **Gate Type:** Usually features an "Amplifying Gate" to handle high di/dt (rate of rise of current) during turn-on. ### B. The Package (K-PUK) * **Hermetic Seal:** The ceramic housing is vacuum-sealed to protect the silicon from moisture and contaminants. * **Pressure Contact:** Unlike soldered components, these rely on external mechanical pressure to maintain electrical and thermal contact. * **Double-Sided Cooling:** The flat metal surfaces (Anode and Cathode) allow heat to be dissipated from both sides, which is essential for managing the massive thermal load at >1000A. --- ## 3. Terminal Identification Because it is a "Hockey-puck" style, the terminals are identified by their physical faces and a small lead: | Part | Description | | :--- | :--- | | **Anode** | One large flat metal face (usually marked). | | **Cathode** | The opposite large flat metal face. | | **Gate (Red Lead)** | Small wire used to trigger the device. | | **Auxiliary Cathode (White Lead)** | Used as a reference point for the gate signal to ensure accurate triggering. | --- ## 4. Typical Applications These parts are used in "heavy" electrical engineering where switching needs to be robust and efficient: * **High Power DC Supplies:** Used in electrochemical processes (plating, electrolysis). * **Motor Starters:** Large industrial AC motor soft-starters. * **HVDC Transmission:** Power grid load management. * **Welding:** High-current resistance welding controllers. --- ## 5. Critical Installation Note **Clamping Force:** These devices **must** be installed using a calibrated heat sink clamp. If the pressure is too low, the electrical resistance increases, causing the part to burn out. If the pressure is too high, the silicon wafer may crack. *Required Force for K-PUK usually ranges between **22kN to 24kN**.*