The **CLM4B-RKW-CWBYA363** (commonly referred to as the CLM4B-RKW series) is a high-brightness Surface Mount Device (SMD) LED manufactured by **Cree LED**. It belongs to the PLCC4 (Plastic Leaded Chip Carrier) family and is specifically designed for high-reliability applications like automotive signage and illumination. --- ### 1. Key Technical Specifications The following table summarizes the primary electrical and optical characteristics of the CLM4B-RKW: | Parameter | Specification | | :--- | :--- | | **Color** | Red (624 nm - 634 nm) | | **Package Type** | PLCC4 SMD | | **Luminous Intensity** | 560 mcd - 1400 mcd | | **Forward Voltage ($V_f$)** | 1.8V (Typ) / 2.6V (Max) | | **Forward Current ($I_f$)** | 30 mA (Continuous) | | **Viewing Angle** | 120 Degrees | | **Operating Temperature** | -40°C to +100°C | --- ### 2. Physical Construction and Pins Unlike standard 2-pin LEDs, the **PLCC4** package has four leads. This design offers several structural advantages: * **Heat Dissipation:** The four leads allow for better thermal transfer to the PCB, ensuring the LED doesn't overheat during continuous operation. * **Circuit Redundancy:** In many configurations, the internal chip is connected to multiple pins to ensure a stable electrical path. * **Dimensions:** The package typically measures **3.2 x 2.8 mm**, making it compact enough for high-density arrays. --- ### 3. Electronic Behavior and Circuitry To integrate this part into an electronic circuit, consider the following: #### A. Driving the LED To prevent burnout, a current-limiting resistor is required. Using Ohm's Law ($R = (V_{source} - V_f) / I_f$): * **For a 5V Supply:** $R = (5V - 1.8V) / 0.02A = 160 \, \Omega$. * **Dimming:** Pulse Width Modulation (PWM) is the preferred method for dimming these LEDs to maintain color consistency. #### B. Binning and Color Consistency Cree utilizes "Binning," meaning these LEDs are sorted by intensity and color wavelength during manufacturing. When ordering for a large display or automotive light, it is critical to use parts from the same "Bin" to ensure uniform brightness across the entire panel. --- ### 4. Common Applications * **Automotive:** Dashboard backlighting, stop lamps, and turn signals. * **Signs/Signals:** Variable-message signs (VMS) and channel letters. * **Industrial:** Status indicators on control panels where high visibility is required.