The **QTLP320C-R** is a specific surface-mount technology (SMT) Light Emitting Diode (LED) manufactured by Fairchild Semiconductor (now part of ON Semiconductor). It belongs to the subminiature chip LED category, commonly used for status indication in compact electronics. --- ### 1. Key Technical Specifications The following table summarizes the primary electrical and optical characteristics of the QTLP320C-R: | Parameter | Specification | | :--- | :--- | | **Color** | Red | | **Material** | GaAsP on GaP (Gallium Arsenide Phosphide) | | **Package Type** | Subminiature (Right Angle Mount) | | **Peak Wavelength** | 635 nm | | **Luminous Intensity** | 2.0 mcd (typical) @ 20mA | | **Forward Voltage ($V_F$)** | 2.0V (typical) / 2.8V (max) | | **Forward Current ($I_F$)** | 20 mA (recommended) | | **Viewing Angle** | 120° | --- ### 2. Physical and Mechanical Features * **Form Factor:** It is a "Right Angle" LED. This means the light is emitted parallel to the PCB surface rather than perpendicular to it. This is ideal for edge-lighting or indicators visible from the side of a device. * **Dimensions:** Usually follows a standard subminiature footprint (approximately 3.0mm x 2.0mm), allowing for high-density mounting. * **Packaging:** Typically supplied in Tape and Reel (T&R) format for automated pick-and-place assembly. ### 3. Circuit Integration When designing a circuit for the QTLP320C-R, a current-limiting resistor is required to prevent the LED from burning out. **Calculation Example:** If using a 5V power supply: $$R = \frac{V_{source} - V_F}{I_F} = \frac{5V - 2.0V}{0.02A} = 150 \Omega$$ --- ### 4. Common Applications Due to its small size and right-angle orientation, it is frequently found in: 1. **Network Hardware:** Link/Activity lights on routers and switches. 2. **Handheld Devices:** Battery status or power indicators. 3. **Backlighting:** Small LCD panels or membrane switches. 4. **Edge Indicators:** Mounting on the edge of a PCB to shine through a hole in a plastic enclosure.