## Understanding the LTRB-RASF (OSRAM Multi TOPLED®) The **LTRB-RASF** is a high-performance Surface Mount Device (SMD) LED manufactured by **ams OSRAM**. It is categorized as a "Multi TOPLED" because it integrates four separate LED chips within a single package to provide versatile color mixing and high brightness. --- ### 1. Key Technical Specifications The LTRB-RASF is an **RGBW (Red, Green, Blue, White)** LED. This configuration allows for high-quality white light as well as a full spectrum of colors. | Feature | Specification | | :--- | :--- | | **Package Size** | 3.5 mm x 3.2 mm x 2.3 mm (PLCC-6) | | **Colors Integrated** | Red (623nm), True Green (527nm), Blue (470nm), White | | **Common Anode/Cathode** | Independent chips (6-pin configuration) | | **Operating Temperature** | -40°C to +85°C | | **Technology** | Thinfilm (Red), ThinGaN (Green, Blue, White) | | **Viewing Angle** | 120° (Lambertian emitter) | --- ### 2. Functional Components The "Electronic Parts" of this LED refer to the internal semiconductor dies and the package architecture: * **Red Die (InGaAlP):** Uses Thinfilm technology to provide high luminous flux at a dominant wavelength of 623nm. * **Green & Blue Dies (InGaN):** Utilize Indium Gallium Nitride technology for high efficiency. * **White Die:** An InGaN blue chip covered with a yellow phosphor converter to produce white light. * **Lead Frame:** A PLCC-6 (Plastic Leaded Chip Carrier) with 6 pins, allowing for individual control of each color channel. * **Encapsulant:** Clear silicone resin that protects the chips while allowing maximum light extraction. --- ### 3. Typical Driving Characteristics To operate the LTRB-RASF correctly, each color must be driven according to its specific electrical requirements: | Color | Forward Voltage ($V_F$) Typ. | Test Current ($I_F$) | Luminous Intensity ($I_V$) Typ. | | :--- | :--- | :--- | :--- | | **Red** | 2.1 V | 20 mA | 600 mcd | | **True Green** | 3.2 V | 20 mA | 1500 mcd | | **Blue** | 3.2 V | 20 mA | 350 mcd | | **White** | 3.2 V | 20 mA | 1400 mcd | --- ### 4. Applications The LTRB-RASF is primarily used where space is limited but high color quality is required: * **Automotive Interiors:** Dashboard lighting, ambient lighting, and console displays. * **Industrial Lighting:** Status indicators and color-changing signals. * **Backlighting:** Illumination for switches and LCD displays. * **Smart Home:** Mood lighting and decorative RGBW accents. ---