## Technical Overview: QTLP321C-R LED The **QTLP321C-R** is a surface-mount technology (SMT) Light Emitting Diode (LED). It belongs to the subminiature chip LED family, specifically designed in a **1206 (3216 Metric)** package. It is primarily used for status indication, backlighting, and panel illumination. --- ### 1. Key Technical Specifications The following table outlines the fundamental electronic and optical characteristics of the QTLP321C-R: | Parameter | Characteristic | Typical Value | | :--- | :--- | :--- | | **Material** | Semiconductor Type | GaAsP on GaP | | **Color** | Emitted Color | **Red** | | **Wavelength** | Peak Emission | 635 nm | | **Forward Voltage ($V_F$)** | Typical Operating Voltage | 2.0 V (Max 2.8 V) | | **Forward Current ($I_F$)** | Recommended Operating Current | 20 mA | | **Luminous Intensity ($I_V$)** | Brightness | 15 mcd | | **Viewing Angle** | Beam Spread | 130° | | **Package Style** | Case Size | 1206 (3.2mm x 1.6mm) | --- ### 2. Physical Design & Construction * **Clear Lens:** The device typically features a water-clear lens to maximize light output and clarity. * **Subminiature Profile:** Its low profile (approx. 1.1mm height) makes it ideal for compact electronic assemblies where space is at a premium. * **Tape and Reel:** It is usually supplied in 8mm tape on 7" diameter reels for automated pick-and-place machinery. --- ### 3. Absolute Maximum Ratings To ensure the longevity of the component, the following limits should not be exceeded: | Limit Description | Value | | :--- | :--- | | **Power Dissipation** | 100 mW | | **Continuous Forward Current** | 30 mA | | **Peak Forward Current** (1/10 Duty Cycle) | 160 mA | | **Reverse Voltage** | 5 V | | **Operating Temperature** | -40°C to +85°C | --- ### 4. Implementation Example When integrating the QTLP321C-R into a circuit (e.g., using a 5V power source), you must use a current-limiting resistor to prevent burnout. **Calculation:** $R = (V_{source} - V_F) / I_F$ $R = (5V - 2.0V) / 0.02A = 150 \Omega$ ```cpp // Typical Hardware Logic // [Source 5V] ---> [150 Ohm Resistor] ---> [QTLP321C-R Anode] // [QTLP321C-R Cathode] ---> [GND] ```