The **SMP4-RGY** is a specific type of surface-mount (SMD) LED. It is categorized as a **PLCC-4** package multi-color LED, capable of emitting Red, Green, and Yellow light. Below is a detailed breakdown of its electronic characteristics and specifications. --- ## 1. Technical Specifications The SMP4-RGY typically follows these standard electrical parameters: | Parameter | Red (R) | Green (G) | Yellow (Y) | | :--- | :--- | :--- | :--- | | **Forward Voltage ($V_F$)** | 1.8V - 2.4V | 1.9V - 2.5V | 1.8V - 2.4V | | **Luminous Intensity** | ~50 - 100 mcd | ~40 - 80 mcd | ~50 - 100 mcd | | **Peak Wavelength** | ~630 nm | ~570 nm | ~590 nm | | **Forward Current ($I_F$)** | 20mA - 30mA | 20mA - 30mA | 20mA - 30mA | | **Viewing Angle** | 120° | 120° | 120° | --- ## 2. Pin Configuration (PLCC-4) The "4" in SMP4 refers to the four leads on the package. Because this is a multi-color LED, the internal wiring is usually configured in a **Common Cathode** or **Common Anode** arrangement, or as a dual-chip series depending on the specific sub-manufacturer (like Bivar). ### Typical Pinout Diagram | Pin Number | Function | | :--- | :--- | | **Pin 1** | Cathode (Common) | | **Pin 2** | Anode - Red | | **Pin 3** | Anode - Green | | **Pin 4** | Anode - Yellow (or combined R+G) | *Note: In many RGY models, the "Yellow" is achieved by lighting Red and Green simultaneously, but the SMP4-RGY often includes a dedicated Yellow die or a specific phosphor/wafer combination.* --- ## 3. Key Features * **Package Type:** PLCC-4 (Plastic Leaded Chip Carrier). These are robust, heat-resistant, and suitable for automated SMT (Surface Mount Technology) assembly. * **Color Mixing:** By PWM (Pulse Width Modulation) controlling the Red and Green channels, you can achieve various shades of orange and lime in addition to the primary R, G, and Y. * **Form Factor:** Small footprint (typically 3.2mm x 2.8mm), making it ideal for high-density circuit boards. * **Reliability:** Designed for industrial and automotive indicator applications with a wide operating temperature range (-40°C to +85°C). --- ## 4. Example Driving Circuit (Arduino/Microcontroller) To safely operate the SMP4-RGY, current-limiting resistors must be used for each anode. ```cpp // Example: Setting a Yellow-ish color using PWM int redPin = 9; int greenPin = 10; void setup() { pinMode(redPin, OUTPUT); pinMode(greenPin, OUTPUT); } void loop() { // Mix Red and Green to enhance Yellow output analogWrite(redPin, 255); analogWrite(greenPin, 150); } ``` --- ## 5. Applications * **Status Indicators:** Used in networking equipment (Routers/Switches) to show Link, Activity, or Error status. * **Control Panels:** Industrial machinery displays where different states (Stop, Go, Caution) are required. * **Automotive:** Dashboard illumination and button backlighting.