The **SFH 4256-R** is a high-power Infrared (IR) Emitter manufactured by ams OSRAM. It belongs to the Power TOPLED® family and is specifically designed for high-performance optical sensing and data transmission. --- ### ## Technical Specifications Below are the primary electronic characteristics of the SFH 4256-R: | Parameter | Symbol | Typical Value | Unit | | :--- | :--- | :--- | :--- | | **Peak Wavelength** | $\lambda_{peak}$ | 850 | nm | | **Forward Current** | $I_F$ | 70 | mA | | **Forward Voltage** | $V_F$ | 1.5 (max 1.8) | V | | **Radiant Intensity** | $I_e$ | 10 - 20 | mW/sr | | **Switching Times** | $t_r / t_f$ | 12 / 12 | ns | | **Viewing Angle** | $\phi$ | ± 60 | Degrees | --- ### ### Key Electronic Features 1. **High Speed:** With rise and fall times of approximately 12 nanoseconds, this component is suitable for high-frequency modulation and fast data links. 2. **850nm Technology:** It operates in the near-infrared spectrum. While 850nm is mostly invisible to the human eye, it can sometimes show a faint red glow, and it is highly sensitive to standard silicon phototransistors. 3. **Power TOPLED Package:** The "R" in the suffix often denotes specific binning or tape-and-reel orientation. The package is designed for Surface Mount Technology (SMT) and offers excellent thermal management. 4. **ESD Robustness:** It features a high ESD withstand voltage (up to 2 kV according to ANSI/ESDA/JEDEC JS-001), protecting the internal Gallium Aluminum Arsenide (GaAlAs) chip. --- ### ### Typical Applications * **Infrared Illumination:** Used for cameras and CCTV night vision. * **Data Transmission:** High-speed IR communication (IrDA). * **Proximity Sensors:** Used in industrial automation and consumer electronics. * **Touchscreens:** Specifically infrared-based touch frames. --- ### ### Circuit Design Considerations When integrating the SFH 4256-R into a circuit, consider the following: * **Current Limiting:** Always use a series resistor to prevent thermal runaway. * **Heat Dissipation:** Although it is a small SMT device, continuous operation at 70mA requires a proper PCB copper area for heat sinking. * **Polarity:** Ensure the cathode (marked with a notch or corner chamfer on the package) is connected to the negative terminal.