The **QBLP655-R** is a surface-mount (SMD) Light Emitting Diode (LED) manufactured by **QT-Brightek**. It is a sub-miniature, red-colored LED commonly used in indicators and backlighting due to its compact footprint. --- ### 1. Technical Specifications The following table summarizes the key electrical and optical characteristics of the QBLP655-R: | Parameter | Specification | | :--- | :--- | | **Emitted Color** | Red | | **Package Type** | 1205 (3212 Metric) | | **Material** | AlGaInP (Aluminum Gallium Indium Phosphide) | | **Peak Wavelength** | 630 nm - 635 nm | | **Luminous Intensity** | 50 mcd - 130 mcd @ 20mA | | **Forward Voltage ($V_f$)** | 1.7V (Min) - 2.5V (Max) | | **Viewing Angle** | 140° | | **Operating Temp** | -40°C to +85°C | --- ### 2. Key Features * **Reverse Mount Design:** The "655" series is specifically designed for reverse mounting, where the LED shines through a hole in the PCB. * **High Reliability:** Built using AlGaInP technology, ensuring long life and stable light output. * **Low Profile:** The thin package makes it ideal for height-constrained applications. * **Moisture Sensitivity:** Typically rated at MSL 3, requiring proper handling and storage. --- ### 3. Pinout and Dimensions The QBLP655-R uses a standard 1205 package footprint. Designers must pay close attention to the polarity marking (usually a green line or notch on the cathode side). * **Anode (+):** Connected to the positive side of the DC supply. * **Cathode (-):** Connected to the ground or current-limiting resistor. #### Typical Circuit Connection ```c [VCC] --- [Resistor] --- [Anode (LED) Cathode] --- [GND] // To calculate the resistor (R): // R = (V_source - V_f) / I_f // For 5V supply at 20mA: // R = (5V - 2.0V) / 0.020A = 150 Ohms ``` --- ### 4. Common Applications 1. **Status Indicators:** Power lights for consumer electronics. 2. **Backlighting:** Illuminating membrane switches or LCD panels from behind the PCB. 3. **Wearables:** Low power consumption and small size are ideal for portable devices. 4. **Automotive:** Interior dashboard lighting and button illumination.