SMD Infrared LED 0.8mm Height Flat Top - 1.6V - 875nm - 110mW - English Technical Datasheet

1. Product Overview

This document provides the complete technical specifications for a miniature, surface-mount infrared (IR) emitting diode. The device is designed for applications requiring a compact, reliable source of infrared light matched to silicon photodetectors.

1.1 Core Features and Positioning

The LED is characterized by its exceptionally low profile of 0.8mm, making it suitable for space-constrained PCB designs. It features a flat-top lens molded from clear plastic, which provides a specific radiation pattern. The device is constructed using a GaAlAs (Gallium Aluminum Arsenide) chip material, which is optimized for infrared emission. A key design advantage is its spectral output, which is closely matched to the sensitivity curve of common silicon photodiodes and phototransistors, maximizing detection efficiency in sensor systems.

1.2 Compliance and Environmental Specifications

The component is compliant with major environmental and safety directives. It is manufactured as a Pb-free (lead-free) product. It also complies with halogen-free requirements, specifically limiting Bromine (Br) and Chlorine (Cl) content to less than 900 ppm individually and a combined total of less than 1500 ppm. The product is designed to remain within the parameters of the RoHS (Restriction of Hazardous Substances) directive.

2. Technical Parameter Analysis

This section details the absolute limits and standard operating characteristics of the infrared LED. All parameters are specified at an ambient temperature (Ta) of 25°C unless otherwise noted.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation under or at these limits is not guaranteed.

• Continuous Forward Current (I_F): 65 mA
• Reverse Voltage (V_R): 5 V
• Operating Temperature (T_opr): -25°C to +85°C
• Storage Temperature (T_stg): -40°C to +85°C
• Soldering Temperature (T_sol): 260°C for a duration not exceeding 5 seconds.
• Power Dissipation (P_d): 110 mW (at or below 25°C free air temperature).

2.2 Electro-Optical Characteristics

These parameters define the typical performance of the device under standard test conditions (I_F = 20mA, Ta=25°C).

• Radiant Intensity (I_e): 0.2 mW/sr (Minimum), 0.5 mW/sr (Typical). This measures the optical power emitted per unit solid angle.
• Peak Wavelength (λ_p): 875 nm (Typical). This is the wavelength at which the optical output is strongest.
• Spectral Bandwidth (Δλ): 80 nm (Typical). This indicates the range of wavelengths emitted, typically measured at half the peak intensity (FWHM).
• Forward Voltage (V_F): 1.3 V (Typical), 1.6 V (Maximum). The voltage drop across the LED when conducting 20mA.
• Reverse Current (I_R): 10 µA (Maximum). The leakage current when 5V is applied in reverse bias.
• View Angle (2θ_1/2): 145° (Typical). The full angle at which the radiant intensity is half of the peak intensity (at 0°). The flat-top lens contributes to this wide viewing angle.

3. Performance Curve Analysis

The datasheet includes several graphs illustrating the device's behavior under varying conditions. These curves are essential for design engineers to predict performance in real-world applications.

3.1 Forward Current vs. Ambient Temperature

This curve shows the derating of the maximum allowable forward current as the ambient temperature increases. To prevent thermal damage, the forward current must be reduced when operating above 25°C. The power dissipation rating of 110mW is a critical factor in this derating calculation.

3.2 Spectral Distribution

The graph depicts the relative optical power output across the wavelength spectrum. It confirms the peak emission at approximately 875nm and the ~80nm spectral bandwidth, highlighting the match with silicon detector sensitivity (which peaks around 800-900nm).

3.3 Relative Intensity vs. Forward Current

This plot illustrates the relationship between the drive current and the light output. It typically shows a sub-linear trend, where increasing the current yields diminishing returns in radiant intensity, especially as thermal effects become significant. This informs decisions on drive current for desired output versus efficiency and device lifetime.

3.4 Forward Current vs. Forward Voltage

The IV (Current-Voltage) curve is fundamental for circuit design. It shows the exponential relationship, allowing designers to calculate the necessary series resistor for a given supply voltage to achieve the target drive current (e.g., 20mA). The typical V_F of 1.3V is a key value for these calculations.

3.5 Relative Radiant Intensity vs. Angular Displacement

This polar plot visually represents the radiation pattern or view angle. The 145° viewing angle is confirmed here, showing how intensity decreases as the angle from the central axis (0°) increases. This is crucial for aligning the LED with a detector in sensor applications.

4. Mechanical and Packaging Information

4.1 Package Dimensions

The device is housed in a very compact surface-mount package. Key dimensions include a body size of approximately 1.6mm x 1.2mm with a total height of 0.8mm. The anode and cathode pads are located on the bottom of the package. Detailed mechanical drawings in the datasheet provide all critical dimensions with a standard tolerance of ±0.1mm unless otherwise specified. A suggested land pattern (footprint) for PCB design is provided as a reference, but designers are advised to modify it based on their specific assembly process and reliability requirements.

4.2 Polarity Identification

The package includes a polarity indicator, typically a notch or a mark on one end, to distinguish the anode from the cathode. Correct orientation is vital for circuit operation.

4.3 Packaging for Assembly

The components are supplied on tape and reel for compatibility with automated pick-and-place assembly equipment. The tape width is 8mm, wound on a standard 7-inch diameter reel. Each reel contains 3000 pieces. Carrier tape dimensions are provided to ensure compatibility with feeder systems.

5. Soldering and Assembly Guidelines

Proper handling is critical to maintain device reliability and performance.

5.1 Storage and Moisture Sensitivity

The LEDs are packaged in a moisture-proof bag with desiccant. The bag should not be opened until the components are ready for use. Before opening, store at 10-30°C with ≤90% RH. After opening, the "floor life" is 168 hours (7 days) when stored at 10-30°C and ≤60% RH. Unused parts must be re-bagged with desiccant. If the floor life or shelf life is exceeded, baking at 60°C ±5°C for 96 hours is required before use to remove absorbed moisture and prevent "popcorning" during reflow soldering.

5.2 Reflow Soldering Profile

A recommended Pb-free reflow soldering temperature profile is provided. Key parameters include a preheat stage, a defined ramp-up rate, a peak temperature not exceeding 260°C, and a time above liquidus (TAL) appropriate for the solder paste. Reflow soldering should not be performed more than two times on the same device. Stress on the LED body during heating and warping of the PCB after soldering must be avoided.

5.3 Hand Soldering and Rework

If hand soldering is necessary, extreme care is required. The soldering iron tip temperature should be below 350°C, applied to each terminal for no more than 3 seconds. A low-power iron (≤25W) is recommended. A cooling interval of at least 2 seconds should be allowed between soldering the two terminals. Rework is strongly discouraged after the LED is soldered. If unavoidable, a specialized dual-tip soldering iron must be used to simultaneously heat both terminals and lift the component without applying mechanical stress. The impact of rework on device characteristics must be verified beforehand.

6. Application Notes and Design Considerations

6.1 Primary Application Scenarios

• PCB-Mounted Infrared Sensors: Proximity sensing, object detection, line following.
• Infrared Remote Control Units: Suitable for designs requiring higher output power for extended range.
• Scanners: Barcode readers, document scanners.
• General Infrared Systems: Any application requiring a compact, efficient IR source paired with a silicon detector.

6.2 Critical Design Considerations

• Current Limiting: An external series resistor is MANDATORY. The LED's exponential IV characteristic means a small increase in voltage can cause a large, destructive increase in current. The resistor value is calculated using R = (V_supply - V_F) / I_F.
• Thermal Management: The 110mW power dissipation limit must be respected. Consider PCB copper area (thermal pads) for heat sinking, especially when driving at higher currents or in elevated ambient temperatures.
• Optical Alignment: The wide 145° viewing angle simplifies alignment but reduces intensity at a specific point. For focused beams, external optics may be required.
• Electrical Protection: The low reverse voltage rating (5V) means care must be taken to avoid reverse bias conditions, which could be caused by inductive loads or incorrect PCB layout.

6.3 Comparison and Selection Factors

When selecting an IR LED, key differentiating factors include:
Package Size/Height: This device's 0.8mm profile is a major advantage for ultra-thin designs.
Viewing Angle: The flat-top, wide-angle lens is ideal for broad coverage, whereas domed lenses offer more focused beams.
Wavelength: The 875nm peak is a standard matched to silicon. Other wavelengths (e.g., 940nm) offer lower visibility but may have slightly lower detector response.
Radiant Intensity: The 0.5mW/sr typical output is suitable for many medium-range applications. Higher-output devices are available but may trade off size or viewing angle.

7. Labeling and Ordering Information

The reel label contains essential information for traceability and production control. Fields typically include: Customer Part Number (CPN), Manufacturer Part Number (P/N), Lot Number (LOT No), Quantity (QTY), Peak Wavelength (H.E.), Performance Rank (CAT), Reference Code (REF), Moisture Sensitivity Level (MSL-X), and Country of Manufacture (Made In). The specific part number for this device is SIR19-21C/TR8, where "TR8" indicates the 8mm tape on reel packaging.

8. Technical Principles and Trends

8.1 Operating Principle

An infrared LED is a semiconductor p-n junction diode. When forward biased, electrons and holes recombine in the active region (the GaAlAs chip), releasing energy in the form of photons. The specific bandgap energy of the GaAlAs material determines the photon wavelength, resulting in infrared light around 875nm. The clear epoxy lens protects the chip and shapes the emitted light pattern.

8.2 Industry Trends

The trend in SMD optoelectronics continues toward miniaturization, higher efficiency, and greater integration. There is increasing demand for even smaller package footprints and lower heights to enable thinner consumer electronics. Advances in chip design and packaging materials aim to deliver higher radiant intensity from smaller devices while maintaining or improving reliability. Integration with drivers and sensors in multi-chip modules (MCMs) or system-in-package (SiP) solutions is also a growing area, simplifying design and saving board space.