The **C4SMM-RJF** is a high-brightness, through-hole Oval LED manufactured by **Cree LED** (now part of SGH). It is specifically designed for full-color outdoor video screens and digital signage. --- ### 1. Key Technical Specifications The following table highlights the primary electronic and optical characteristics of the C4SMM-RJF (Red LED). | Parameter | Specification | | :--- | :--- | | **Color** | Red (621nm - 624nm) | | **Luminous Intensity** | 770 mcd (min) - 2130 mcd (max) | | **Forward Current ($I_F$)** | 50 mA (Maximum) | | **Forward Voltage ($V_F$)** | 2.1V (Typical) / 2.6V (Maximum) | | **Viewing Angle** | 100° Horizontal / 45° Vertical (Oval) | | **Package Type** | 4mm Through-Hole (Radial) | | **Operating Temperature** | -40°C to +100°C | --- ### 2. Physical Design Features * **Oval Shape:** The 4mm oval lens is engineered to provide a wide horizontal viewing angle (100°) and a narrower vertical angle (45°). This is optimized for spectators viewing large screens from the ground or sides. * **Standoffs:** The "RJF" suffix often refers to the specific lead frame design, typically including **standoffs** (small protrusions on the legs) to ensure proper spacing from the PCB during soldering. * **Epoxy Material:** It uses an optical-grade epoxy that contains UV inhibitors to prevent yellowing or degradation when exposed to direct sunlight. --- ### 3. Electronic Behavior * **Current Sensitivity:** As a Red LED (AlGaInP technology), its brightness is highly dependent on the forward current. It is typically driven at 20mA for standard use, but can handle up to 50mA for peak brightness. * **Reverse Voltage:** The device has a maximum reverse voltage ($V_R$) of 5V. Exceeding this can cause permanent damage to the junction. * **Thermal Management:** Because this LED can be driven at relatively high currents for its size, proper PCB airflow is required to prevent "thermal runaway," where heat causes the forward voltage to drop, leading to even more current draw. --- ### 4. Common Applications * **Outdoor Signs:** Electronic Bus/Train destination signs. * **Video Screens:** Large-scale LED billboards (like those in Times Square). * **Traffic Signals:** Variable message signs (VMS) on highways.