Sidelooker Infrared LED IR928-6C-F Datasheet - 2.54mm Lead Spacing - 940nm Wavelength - 50mA Current - 75mW Power - English Technical Document

1. Product Overview

The IR928-6C-F is a high-intensity, side-emitting infrared light-emitting diode (LED). It is designed for applications requiring a compact, side-facing radiation source. The device is molded in a clear plastic package, allowing the infrared radiation from the GaAs chip to be emitted from the side of the component. This package style is particularly useful in space-constrained designs where a top-emitting LED is not suitable.

Key advantages of this device include its high radiant intensity, low forward voltage, and high reliability. It is manufactured to be lead-free (Pb-free), compliant with RoHS, EU REACH, and halogen-free substance restrictions (Br < 900ppm, Cl < 900ppm, Br+Cl < 1500ppm). The standard 2.54mm lead spacing makes it compatible with common through-hole PCB layouts.

2. Technical Specifications Deep Dive

2.1 Absolute Maximum Ratings

The device must not be operated beyond these limits to prevent permanent damage. The continuous forward current (IF) is rated at 50 mA. The maximum reverse voltage (VR) that can be applied is 5 V. The device can operate within an ambient temperature (Topr) range of -25°C to +85°C and can be stored (Tstg) from -40°C to +85°C. The maximum soldering temperature (Tsol) is 260°C for less than 5 seconds. The maximum power dissipation (Pd) at or below 25°C free air temperature is 75 mW.

2.2 Electro-Optical Characteristics

These parameters are specified at a standard test condition of Ta=25°C. The peak emission wavelength (λp) is typically 940nm, with a spectral bandwidth (Δλ) of 50nm, making it suitable for applications in the near-infrared spectrum. The forward voltage (VF) is typically 1.25V at a forward current of 20mA, with a maximum of 1.60V, indicating good electrical efficiency. The reverse current (IR) is a maximum of 10 µA at the full 5V reverse bias. The viewing angle (2θ1/2) is 20 degrees, defining a relatively narrow beam of infrared light emitted from the side of the package.

A critical parameter is the light current (IC(ON)), which is the photocurrent generated in a test phototransistor under specified conditions (IF=4mA, VCE=3.5V). This parameter is used to bin the LEDs into different intensity ranks.

3. Binning System Explanation

The IR928-6C-F is sorted into different ranks based on its radiant intensity, measured as IC(ON). This ensures consistency in performance for end applications. The binning table provides minimum and maximum values for each rank code. For example, rank 5-2 has an IC(ON) range of 1053 to 1870 µA, while rank 7-2 has a range of 306 to 441 µA. It is important to note that this bin table is for reference only, and specific bin shipments are not guaranteed unless specified during ordering. Designers should account for the possible variation in output within the selected rank.

4. Performance Curve Analysis

The datasheet includes several typical characteristic curves that are essential for circuit design and thermal management.

4.1 Forward Current vs. Ambient Temperature

This derating curve shows how the maximum allowable continuous forward current decreases as the ambient temperature increases above 25°C. This is crucial for ensuring long-term reliability and preventing thermal runaway.

4.2 Spectral Distribution

This graph illustrates the relative radiant intensity as a function of wavelength, centered around the 940nm peak. The 50nm bandwidth is visible, showing the spread of emitted wavelengths.

4.3 Forward Current vs. Forward Voltage

The IV curve shows the relationship between the current flowing through the LED and the voltage across it. It is non-linear, typical of a diode. This curve is necessary for designing the current-limiting circuitry.

4.4 Relative Radiant Intensity vs. Angular Displacement

This polar plot visually represents the 20-degree viewing angle, showing how the intensity of the emitted infrared light falls off as you move away from the central axis perpendicular to the side of the package.

5. Mechanical and Package Information

The package is a side-viewing, through-hole design. The anode and cathode are clearly identified in the package drawing. A detailed dimensioned drawing is provided, with all units in millimeters and standard tolerances of ±0.3mm unless otherwise specified. The leads have a standard 2.54mm (0.1 inch) spacing. The drawing specifies critical distances, such as the recommended minimum distance (3mm) from the epoxy bulb to any point of lead bending or soldering to avoid mechanical and thermal stress on the package.

6. Soldering and Assembly Guidelines

6.1 Lead Forming

Leads must be formed before soldering. Bending must occur at least 3mm from the bottom of the epoxy resin bulb. The lead frame must be held securely during bending to avoid stressing the epoxy, which can crack the LED or damage the internal wire bonds. Cutting of leads should be done at room temperature.

6.2 Soldering Process

Both hand soldering and dip/wave soldering parameters are specified. For hand soldering, an iron tip temperature of 300°C max (30W max) with a soldering time of 3 seconds max is recommended. For wave soldering, a preheat of 100°C max for 60 seconds max, followed by a solder bath at 260°C max for 5 seconds max is specified. In all cases, the solder joint must be at least 3mm from the epoxy bulb. A soldering profile diagram is provided, showing the recommended temperature vs. time relationship for wave soldering. Soldering should not be performed more than once. After soldering, the LED must be protected from mechanical shock until it cools to room temperature.

6.3 Storage Conditions

After shipment, LEDs should be stored at 10-30°C and ≤70% relative humidity (RH) for up to 3 months. For longer storage (up to one year), they should be kept in a sealed container with a nitrogen atmosphere at 10-25°C and 20-60% RH. Once the original package is opened, devices should be used within 24 hours or as soon as possible, and stored at 10-25°C and 20-60% RH. Rapid temperature changes in high humidity should be avoided to prevent condensation.

6.4 Cleaning and ESD

Ultrasonic cleaning is not recommended as it can damage the package. The device is sensitive to electrostatic discharge (ESD). Proper ESD precautions, such as using grounded workstations and wrist straps, are strongly recommended during handling.

6.5 Heat Management

Proper thermal design is essential. The operating current must be derated according to the derating curve when the ambient temperature exceeds 25°C. The temperature around the LED in the final application must be controlled to maintain performance and reliability.

7. Packaging and Ordering Information

The standard packing quantity is 1000 pieces per bag, 8 bags per box, and 10 boxes per carton, totaling 80,000 pieces per carton. A label specification is provided, detailing the information printed on the packaging, including fields for Customer Part Number (CPN), Part Number (P/N), Quantity (QTY), Rank (CAT), Reference (REF), and Lot Number (LOT No.).

8. Application Suggestions

8.1 Typical Application Scenarios

The IR928-6C-F is ideal for applications requiring a compact, side-emitting infrared source. Common uses include optical computer mice, where the side emission reflects off a surface to a sensor. It is also used in optoelectronic switches, object detection systems, proximity sensors, and various infrared remote control or data transmission systems where its specific wavelength and form factor are advantageous.

8.2 Design Considerations

When designing with this LED, consider the following: Ensure the PCB hole alignment matches the LED leads perfectly to avoid mechanical stress. Implement appropriate current-limiting resistors based on the forward voltage and desired operating current (staying within the 50mA maximum). Use the derating curve to select a safe operating current for the expected maximum ambient temperature. Position the LED so its side-emitting face is correctly oriented towards the target or sensor. Account for the intensity variation defined by the binning system in the sensitivity of the receiving circuit (e.g., phototransistor or photodiode).

9. Technical Comparison and Differentiation

The primary differentiation of the IR928-6C-F lies in its side-looking package geometry, which is not common among standard infrared LEDs. Compared to top-emitting LEDs, it allows for a lower profile installation when the radiation needs to be directed horizontally. Its 940nm wavelength is a common standard, offering good compatibility with silicon-based photodetectors which have high sensitivity in this range. The combination of relatively high radiant intensity (as defined by its bins) and a narrow 20-degree viewing angle provides a more directed beam compared to LEDs with wider viewing angles, potentially increasing signal strength in aligned systems.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the purpose of the IC(ON) parameter and the binning system?
A: IC(ON) is a measure of the LED's radiant output under standardized test conditions. The binning system groups LEDs with similar output levels. This allows designers to select a consistency level for their application; for critical applications, a tighter bin (e.g., 6-1) may be specified to ensure uniform performance across all units in a production run.

Q: Why is the 3mm distance for lead bending and soldering so important?
A: The epoxy resin bulb and the internal connections (wire bonds) from the chip to the leads are sensitive to heat and mechanical stress. Applying heat or force too close to the bulb can melt the epoxy, crack it, or break the delicate wire bonds, leading to immediate or latent failure of the LED.

Q: Can I drive this LED with a constant voltage source?
A: It is not recommended. LEDs are current-driven devices. Their forward voltage has a tolerance and varies with temperature. Driving with a constant voltage can lead to large, uncontrolled variations in current, potentially exceeding the maximum rating and destroying the LED. Always use a constant current driver or a simple series resistor with a voltage source to set the current.

Q: What does "Pb-free" and "Halogen-Free" mean for my application?
A: These are environmental and regulatory compliance statements. Pb-free means the device does not contain lead, complying with regulations like RoHS. Halogen-free means it contains very low levels of bromine (Br) and chlorine (Cl), which are substances of concern in some environmental regulations and for certain high-reliability or high-temperature applications where halogen byproducts could be problematic.

11. Practical Design and Usage Case

Case: Object Detection Sensor
In a simple break-beam sensor, an IR928-6C-F can be paired with a phototransistor placed opposite it. The LED is driven with a constant current of, for example, 20mA. When an object passes between the LED and the phototransistor, it interrupts the 940nm infrared beam. The phototransistor's output changes, which can be detected by a comparator or microcontroller to trigger an action. The side-emitting package allows both the LED and sensor to be mounted flat on the same PCB, with their active sides facing each other across a gap, creating a very compact sensor assembly. The 20-degree viewing angle helps concentrate the light towards the receiver, improving signal-to-noise ratio. The designer must select an appropriate IC(ON) bin to ensure sufficient signal strength reaches the phototransistor over the desired sensing distance.

12. Principle of Operation

An infrared LED is a semiconductor p-n junction diode. When a forward voltage exceeding its threshold is applied, electrons and holes recombine in the active region of the semiconductor material (Gallium Arsenide, GaAs, in this case). This recombination process releases energy in the form of photons (light). The specific wavelength of 940nm is determined by the bandgap energy of the GaAs material. The clear epoxy package acts as a lens, shaping the emitted light into the specified 20-degree viewing angle from the side of the component. The "sidelooker" design is achieved by mounting the semiconductor chip vertically within the package so that its light-emitting surface faces the side wall.

13. Industry Trends and Developments

The trend in infrared LEDs, including side-emitting types, is towards higher efficiency (more radiant output per electrical watt input), which reduces power consumption and heat generation. There is also a drive for increased reliability and longevity, especially for automotive and industrial applications. Miniaturization continues, although through-hole packages like the IR928-6C-F remain popular for prototyping, hobbyist use, and applications where manual assembly or higher mechanical strength is required. Surface-mount device (SMD) versions of side-emitting IR LEDs are becoming more common for automated high-volume production. The 940nm wavelength remains a industry standard due to its good match with silicon detectors and its relative invisibility compared to visible or 850nm IR light, which can have a faint red glow.