The **LST776-R** is a specific surface-mount technology (SMT) Light Emitting Diode (LED) belonging to the **TOPLED** family, manufactured primarily by ams OSRAM. It is widely used in automotive and industrial applications due to its reliability and standard footprint. --- ### 1. Key Technical Specifications The "R" suffix typically refers to the "Super-Red" color variant. Below are the primary electronic characteristics: | Parameter | Specification | | :--- | :--- | | **Color** | Super-Red (633 nm peak wavelength) | | **Package Type** | PLCC-2 (Standard SMT package) | | **Luminous Intensity** | 11.2 mcd to 28.0 mcd (at 10mA) | | **Forward Voltage ($V_f$)** | Typ. 2.0V (Max 2.6V) | | **Forward Current ($I_f$)** | 30 mA (Maximum continuous) | | **Viewing Angle** | 120° (Lambertian emitter) | | **Operating Temperature** | -40°C to +100°C | --- ### 2. Component Composition The LST776-R is composed of several critical electronic and structural elements: * **Semiconductor Die:** Uses **InGaAlP** (Indium Gallium Aluminum Phosphide) technology, which provides high efficiency for red and amber wavelengths. * **Package (PLCC-2):** A white thermoplastic body that reflects light forward, increasing the effective brightness. * **Encapsulation:** A clear epoxy resin that protects the semiconductor chip from moisture and mechanical stress. * **Lead Frame:** Silver-plated copper alloy for optimal electrical conductivity and heat dissipation. --- ### 3. Application Use Cases Because of its AEC-Q101 qualification (automotive grade), it is found in: 1. **Automotive Interiors:** Backlighting for switches, buttons, and dashboard clusters. 2. **Industrial Controls:** Status indicators on control panels and PLCs. 3. **Consumer Electronics:** Power indicators or display backlighting for white goods (washers/dryers). 4. **Signal Logic:** Often paired with a current-limiting resistor (typically 330Ω to 1kΩ depending on the supply voltage) to indicate logic high/low states. --- ### 4. Typical Circuit Integration When designing with the LST776-R, a series resistor is required to prevent thermal runaway. ```cpp // Basic Calculation for Resistor (R) // R = (V_source - V_forward) / I_forward // Example: 5V Source, 10mA Target Current // R = (5.0V - 2.0V) / 0.010A = 300 Ohms ```