IR204-A 3.0mm Infrared LED Datasheet - 3mm Package - 940nm Wavelength - 100mA Current - English Technical Document

1. Product Overview

The IR204-A is a high-intensity infrared emitting diode housed in a standard 3mm (T-1) blue plastic package. It is designed to emit light at a peak wavelength of 940nm, making it spectrally matched with common phototransistors, photodiodes, and infrared receiver modules. This device is characterized by its high reliability, high radiant intensity, and low forward voltage, making it suitable for various infrared transmission applications.

1.1 Core Advantages

• High Radiant Intensity: Delivers strong infrared output for reliable signal transmission.
• Wavelength Matching: The 940nm peak wavelength is optimized for compatibility with standard IR receivers.
• Compact and Standardized: The 3mm package with 2.54mm lead spacing allows for easy integration into standard PCB layouts.
• Compliance: The product is compliant with RoHS, EU REACH, and halogen-free standards (Br < 900ppm, Cl < 900ppm, Br+Cl < 1500ppm).

1.2 Target Applications

This infrared LED is primarily intended for systems requiring non-visible light communication. Key application areas include infrared remote control units with high power requirements, free-air transmission systems, smoke detectors, and other general infrared-based sensing or communication systems.

2. Technical Parameters: In-Depth Objective Interpretation

2.1 Absolute Maximum Ratings

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

• Continuous Forward Current (IF): 100 mA. The maximum DC current that can be continuously applied.
• Peak Forward Current (IFP): 1.0 A. This high current is permissible only under pulsed conditions (Pulse Width ≤ 100μs, Duty Cycle ≤ 1%).
• Reverse Voltage (VR): 5 V. Exceeding this voltage in reverse bias can damage the diode junction.
• Operating & Storage Temperature (Topr/Tstg): -40°C to +85°C. The device is rated for industrial temperature ranges.
• Power Dissipation (Pd): 150 mW at 25°C. The maximum power the package can dissipate without exceeding its thermal limits.

2.2 Electro-Optical Characteristics

These parameters are measured at a standard junction temperature of 25°C and define the device's performance under specified conditions.

• Radiant Intensity (Ie): A key performance metric. At a standard drive current of 20mA, the typical radiant intensity is 5.6 mW/sr. Under high-current pulsed operation (100mA, 1A), the output increases significantly to 38 mW/sr and 350 mW/sr respectively, enabling long-range or high-brightness pulsed applications.
• Peak Wavelength (λp): 940 nm (typical). This is in the near-infrared spectrum, invisible to the human eye but efficiently detected by silicon-based sensors.
• Spectral Bandwidth (Δλ): Approximately 45 nm. This defines the spectral width of the emitted light around the peak wavelength.
• Forward Voltage (VF): Typically 1.2V at 20mA, increasing with current. This low voltage contributes to lower power consumption in designs.
• View Angle (2θ1/2): 35 degrees. This is the angular spread at which the radiant intensity drops to half of its peak value, defining the beam pattern.

3. Binning System Explanation

The datasheet includes a radiant intensity binning structure. LEDs are sorted into groups (K, L, M, N) based on their measured output at IF=20mA. For example, bin 'L' has a minimum intensity of 5.6 mW/sr and a maximum of 8.9 mW/sr. This allows designers to select parts with guaranteed minimum performance levels for consistent system behavior. The datasheet does not indicate binning for wavelength or forward voltage for this specific part number.

4. Performance Curve Analysis

The datasheet provides several characteristic curves that are crucial for design.

4.1 Forward Current vs. Ambient Temperature (Fig.1)

This curve shows how the maximum allowable continuous forward current derates as the ambient temperature increases above 25°C. Designers must use this graph to ensure the operating current does not exceed the safe limit at the application's maximum ambient temperature.

4.2 Spectral Distribution (Fig.2)

Illustrates the relative radiant power as a function of wavelength, centered around the 940nm peak with the specified ~45nm bandwidth.

4.3 Peak Emission Wavelength vs. Temperature (Fig.3)

Shows the shift in peak wavelength with changes in ambient (and thus junction) temperature. This is important for applications where precise spectral matching with a detector is critical.

4.4 Forward Current vs. Forward Voltage (IV Curve) (Fig.4)

Depicts the non-linear relationship between current and voltage. The curve is essential for designing the current-limiting circuitry (e.g., series resistor calculation).

4.5 Relative Intensity vs. Forward Current (Fig.5)

Demonstrates that the light output is not linearly proportional to current, especially at higher currents where efficiency may drop due to heating and other effects.

4.6 Relative Radiant Intensity vs. Angular Displacement (Fig.6)

This is the spatial radiation pattern, graphically showing the 35-degree view angle. It is vital for optical design to ensure proper alignment and coverage.

5. Mechanical and Package Information

5.1 Package Dimensions

The device uses a standard T-1 (3mm) round package. The detailed mechanical drawing in the datasheet provides all critical dimensions including body diameter (3.0mm typical), lead spacing (2.54mm), and lead diameter. Tolerances are typically ±0.25mm unless otherwise specified. The package material is blue-tinted plastic, which acts as a built-in filter.

5.2 Polarity Identification

The longer lead is the anode (+), and the shorter lead is the cathode (-). This is the standard convention for LEDs. The flat side on the rim of the package may also indicate the cathode side.

6. Soldering and Assembly Guidelines

• Soldering Temperature: The maximum soldering temperature is 260°C.
• Soldering Time: The leads should not be exposed to soldering temperatures above 260°C for more than 5 seconds.
• General Handling: Standard ESD (Electrostatic Discharge) precautions should be observed during handling and assembly to prevent damage to the semiconductor junction.
• Storage Conditions: The device should be stored within its specified temperature range of -40°C to +85°C in a dry environment.

7. Packaging and Ordering Information

7.1 Packing Specification

The LEDs are typically packed in bags (200-1000 pieces per bag). Four bags are placed in a box, and ten boxes constitute one carton.

7.2 Label Information

The label on the packaging includes key information such as the Part Number (P/N), quantity (QTY), rank/bin (CAT), peak wavelength (HUE), lot number (LOT No.), and a reference code. This traceability is important for quality control.

8. Application Suggestions

8.1 Typical Application Circuits

In a basic circuit, the LED is driven by a voltage source through a current-limiting resistor. The resistor value (R) is calculated using Ohm's Law: R = (Vcc - Vf) / If, where Vcc is the supply voltage, Vf is the LED's forward voltage (e.g., 1.2V at 20mA), and If is the desired forward current. For pulsed operation (e.g., in remote controls), a transistor switch is typically used to provide the high peak current (up to 1A) from a capacitor or directly from the power supply.

8.2 Design Considerations

• Current Driving: Always drive an LED with a controlled current, not a fixed voltage. Use a series resistor or a constant current driver.
• Thermal Management: While the package has low thermal resistance, continuous operation at high currents (approaching 100mA) or in high ambient temperatures requires consideration of the derating curve to avoid overheating.
• Optical Alignment: The 35-degree view angle requires proper alignment with the receiving sensor for optimal signal strength. Lenses or reflectors can be used to modify the beam pattern if needed.
• Power Supply Noise: In sensitive analog sensing applications, ensure the LED driver circuit does not introduce electrical noise that could interfere with the weak signal from the detector.

9. Technical Comparison and Differentiation

The IR204-A's primary differentiators are its combination of a standard 3mm package, high pulsed radiant intensity (up to 350 mW/sr), and a precisely defined 940nm wavelength. Compared to generic IR LEDs, it offers guaranteed minimum performance (via binning) and compliance with modern environmental regulations. Its GaAlAs chip material is standard for efficient infrared emission.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 Can I drive this LED directly from a 5V or 3.3V microcontroller pin?

No, not directly. A microcontroller pin typically cannot source 20mA continuously (check your MCU's datasheet), and it certainly cannot provide the 1A peak current. More importantly, you must use a series resistor to limit the current to the desired value (e.g., 20mA). A transistor (BJT or MOSFET) is required to switch the higher currents needed for the LED.

10.2 Why is the radiant intensity so much higher under pulsed conditions?

The higher pulsed ratings (100mA, 1A) allow the junction to be driven with much more current for very short durations. This generates more light without causing the average junction temperature to rise to destructive levels, as the thermal mass of the chip and package has time to cool between pulses. This is ideal for burst communication like remote controls.

10.3 What does \"spectrally matched with phototransistor\" mean?

Silicon-based phototransistors and photodiodes have peak sensitivity in the near-infrared region, around 800-900nm. The IR204-A's 940nm emission falls within this high-sensitivity band, ensuring the detector receives a strong signal, which improves the signal-to-noise ratio and operating distance of the system.

11. Practical Design and Usage Case

Case: Simple Infrared Remote Control Transmitter. A common use is in a TV remote. A microcontroller generates a modulated digital code (e.g., 38kHz carrier). This signal drives the base of a transistor. The transistor switches the collector current through the IR204-A. A capacitor near the LED may provide the brief high current pulse (up to 100mA or more) needed for a strong signal. The LED is pulsed at the 38kHz frequency. The 940nm light is invisible, and the high pulsed intensity allows the signal to be reflected off walls and still be detected by the receiver across a room. The low forward voltage helps conserve battery power.

12. Principle Introduction

An Infrared Light Emitting Diode (IR LED) is a semiconductor p-n junction diode. When a forward voltage is applied, electrons from the n-region and holes from the p-region are injected into the junction region. When these charge carriers recombine, they release energy. In this specific device, the semiconductor material (Gallium Aluminum Arsenide - GaAlAs) is chosen so that this energy is released primarily as photons of light in the infrared spectrum (wavelength of 940 nanometers). The blue plastic package acts as a filter, potentially blocking some visible light and may also serve as a lens to shape the output beam.

13. Development Trends

Trends in infrared LED technology include the development of devices with even higher wall-plug efficiency (more light output per electrical watt input), which enables longer battery life or longer range. There is also ongoing work to produce LEDs with narrower spectral bandwidths for applications requiring precise wavelength control and to reduce sensitivity to ambient light noise. Integration of the LED with a driver IC or a photodetector into a single module is another trend, simplifying system design. The push for higher power density in smaller packages continues, alongside the universal industry drive for full compliance with environmental and safety regulations.