5mm Infrared LED SIR333-A Datasheet - 5.0mm Package - 1.65V Forward Voltage - 875nm Wavelength - 150mW Power Dissipation - English Technical Document

1. Product Overview

The SIR333-A is a high-intensity 5mm Infrared (IR) Emitting Diode. It is molded in a blue plastic package and is designed for applications requiring reliable infrared emission. The device's spectral output is matched with common phototransistors, photodiodes, and infrared receiver modules, making it suitable for various sensing and transmission systems.

1.1 Core Features and Advantages

• High Reliability: Designed for consistent long-term performance.
• High Radiant Intensity: Delivers strong infrared output for effective signal transmission.
• Specific Wavelength: Peak emission wavelength (λp) of 875nm.
• Standard Lead Spacing: 2.54mm pin spacing for easy PCB mounting.
• Low Forward Voltage: Contributes to energy-efficient operation.
• Environmental Compliance: The product is Pb-Free, compliant with RoHS, EU REACH, and Halogen-Free standards (Br < 900ppm, Cl < 900ppm, Br+Cl < 1500ppm).

1.2 Target Applications

• Free air transmission systems.
• Infrared remote control units with high power requirements.
• Smoke detectors.
• General infrared applied systems.

2. Technical Specifications and 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.

2.2 Electro-Optical Characteristics

These are the typical performance parameters measured at an ambient temperature (Ta) of 25°C.

Measurement Tolerances: Forward Voltage: ±0.1V, Radiant Intensity: ±10%, Peak Wavelength: ±1.0nm.

2.3 Thermal Considerations

The device's performance is temperature-dependent. The maximum power dissipation of 150mW is specified at or below 25°C free air temperature. As ambient temperature increases, the allowable power dissipation decreases, which must be considered in thermal design to ensure reliability and prevent overheating.

3. Binning System Explanation

The SIR333-A is available in different performance grades, or \"bins,\" based on its Radiant Intensity measured at a forward current (IF) of 20mA. This allows designers to select a component that precisely matches their application's sensitivity requirements.

There is no separate binning indicated for forward voltage or peak wavelength in the provided data; typical values are used.

4. Performance Curve Analysis

4.1 Forward Current vs. Ambient Temperature

This curve shows the derating of the maximum allowable continuous forward current as the ambient temperature rises above 25°C. Designers must reference this graph to avoid exceeding safe operating limits in elevated temperature environments.

4.2 Spectral Distribution

The graph plots relative radiant intensity against wavelength. It confirms the typical peak wavelength of 875nm and the spectral bandwidth of approximately 80nm (Full Width at Half Maximum). This narrow bandwidth is beneficial for minimizing interference from ambient light and matching optical filters in receivers.

3.3 Peak Emission Wavelength vs. Ambient Temperature

This characteristic shows how the peak wavelength shifts with temperature. Understanding this shift is crucial for applications where the receiver is tuned to a specific wavelength, as system performance may vary across the operating temperature range.

4.4 Forward Current vs. Forward Voltage (IV Curve)

The IV curve is fundamental for circuit design. It shows the non-linear relationship between current and voltage. The typical forward voltage is 1.3V at 20mA, but it increases with current and can vary between units. A current-limiting resistor or constant-current driver is essential.

4.5 Radiant Intensity vs. Forward Current

This plot demonstrates that radiant output increases with forward current, but not linearly. It highlights the significant gain in output when driving the LED at its maximum pulsed current (100mA) compared to the standard 20mA, which is useful for applications requiring longer range or higher signal strength.

4.6 Relative Radiant Intensity vs. Angular Displacement

This polar plot illustrates the view angle or emission pattern. The typical half-angle is 20 degrees, meaning the intensity drops to 50% of its on-axis value at ±20 degrees from the center. This defines the LED's beam width and is critical for aligning it with a receiver or sensor.

5. Mechanical and Package Information

5.1 Package Dimensions

The device is housed in a standard 5mm round LED package. Key dimensions include the overall diameter (5.0mm), the lead spacing (2.54mm), and the lead diameter. A detailed dimensioned drawing is provided in the datasheet for precise PCB footprint design. All unspecified tolerances are ±0.25mm.

5.2 Polarity Identification

The LED has a flat side on the rim of the package, which typically indicates the cathode (negative) lead. The longer lead is usually the anode (positive). Correct polarity must be observed during installation.

6. Soldering and Assembly Guidelines

6.1 Lead Forming

• Bend leads at a point at least 3mm from the base of the epoxy bulb.
• Perform lead forming before soldering.
• Avoid stressing the package during bending.
• Cut leads at room temperature.
• Ensure PCB holes align perfectly with LED leads to avoid mounting stress.

6.2 Soldering Parameters

Hand Soldering: Iron tip temperature: 300°C Max. (30W Max.). Soldering time: 3 sec Max. Maintain a minimum distance of 3mm from the solder joint to the epoxy bulb.
Wave/DIP Soldering: Preheat temperature: 100°C Max. (60 sec Max.). Solder bath temperature: 260°C Max., time: 5 sec Max. Distance from joint to bulb: 3mm Min.
General Rules: Avoid stress on leads at high temperature. Do not solder more than once. Protect the LED from shock while cooling. Avoid rapid cooling processes.

6.3 Cleaning

If necessary, clean only with isopropyl alcohol at room temperature for no more than one minute. Do not use ultrasonic cleaning, as it can damage the internal structure. If ultrasonic cleaning is unavoidable, extreme caution regarding power and assembly condition is required.

6.4 Storage Conditions

Store at 30°C or less and 70% Relative Humidity or less. The recommended storage life after shipping is 3 months. For longer storage (up to one year), use a sealed container with a nitrogen atmosphere and moisture absorbent material. Avoid rapid temperature transitions in humid environments to prevent condensation.

7. Packaging and Ordering Information

7.1 Label Specification

The product label includes several codes: CPN (Customer's Product Number), P/N (Product Number), QTY (Packing Quantity), CAT (Luminous Intensity Rank/Bin), HUE (Dominant Wavelength Rank), REF (Forward Voltage Rank), LOT No. (Lot Number), and a date code (Month).

7.2 Packing Quantities

• 200 to 500 pieces per bag.
• 5 bags per inner carton.
• 10 inner cartons per master (outside) carton.

8. Application Suggestions

8.1 Typical Application Circuits

For basic operation, the LED should be driven with a series current-limiting resistor. The resistor value (R) can be calculated using Ohm's Law: R = (Vsupply - VF) / IF, where VF is the forward voltage from the datasheet (use max value for safety) and IF is the desired forward current (e.g., 20mA). For pulsed operation for longer range (e.g., in remote controls), a transistor switch driven by a microcontroller can be used to provide the high peak current (up to 1A under specified duty cycle).

8.2 Design Considerations

• Optical Alignment: Use the 20-degree view angle to properly align the LED with the receiver's field of view.
• Current Drive: Always use a constant current or a current-limiting resistor. Connecting directly to a voltage source will destroy the LED.
• Thermal Management: Ensure the PCB and environment allow for adequate heat dissipation, especially if operating near maximum ratings.
• Receiver Matching: Choose a photodetector or receiver module whose peak sensitivity aligns with the 875nm emission of this LED.
• Ambient Light Immunity: For systems used in environments with varying light, consider modulating the IR signal and using a receiver with a matching modulation frequency to reject ambient noise.

9. Technical Comparison and Differentiation

The SIR333-A differentiates itself through its combination of high radiant intensity (up to 90 mW/sr pulsed) and a relatively narrow 20-degree view angle. This makes it particularly suitable for applications requiring directed, high-power IR beams, such as long-range remote controls or specific sensor applications. Its compliance with modern environmental standards (RoHS, REACH, Halogen-Free) is also a key advantage for products targeting global markets. The availability in intensity bins allows for cost optimization based on performance needs.

10. Frequently Asked Questions (FAQs)

10.1 What is the difference between continuous and pulsed forward current ratings?

The continuous forward current (100mA) is the maximum current the LED can handle indefinitely at 25°C. The peak forward current (1.0A) is a much higher current it can tolerate only for very short pulses (≤100μs) at a very low duty cycle (≤1%). This allows for brief, high-intensity bursts of light for long-range transmission without overheating.

10.2 How do I select the correct current-limiting resistor?

Use the formula R = (Vsupply - VF) / IF. For a 5V supply and driving at 20mA, using the maximum VF of 1.65V: R = (5 - 1.65) / 0.02 = 167.5 Ohms. A standard 180 Ohm or 150 Ohm resistor would be a safe choice. Always calculate using the maximum VF to ensure the current does not exceed the desired limit.

10.3 Can I use this LED for data transmission?

Yes, its fast GaAlAs chip material allows it to be modulated at high speeds, suitable for IR data links. The high radiant intensity also supports longer link distances. The design must use appropriate driver circuitry to achieve the required modulation speed.

10.4 Why is the storage condition important?

The epoxy package can absorb moisture from the air. During the high-temperature soldering process, this trapped moisture can rapidly expand, causing internal cracks or delamination (\"popcorning\"), which can lead to immediate or latent failure. Proper storage minimizes this risk.

11. Practical Design and Usage Case

11.1 Case Study: Long-Range IR Remote Control

Objective: Design a remote control that works reliably from up to 15 meters in a typical living room environment.
Solution: Use the SIR333-A driven in pulsed mode. A microcontroller generates a 38kHz carrier signal modulated with the command data. A transistor switch drives the LED with pulses at the peak current of 1A (with ≤1% duty cycle). This high-intensity pulsed output provides the necessary signal strength for the longer range. The receiver module on the TV is tuned to 38kHz, providing excellent rejection of ambient light and noise.

12. Principle Introduction

An Infrared Light Emitting Diode (IR LED) is a semiconductor p-n junction diode that emits non-visible infrared light when electrically biased in the forward direction. Electrons recombine with holes within the device, releasing energy in the form of photons. The wavelength of the emitted light is determined by the energy bandgap of the semiconductor material. The SIR333-A uses Gallium Aluminum Arsenide (GaAlAs), which provides an efficient emission in the near-infrared spectrum around 875nm.

13. Development Trends

The general trend in IR LED technology is towards higher efficiency (more radiant output per electrical watt input), increased power density for longer-range applications, and smaller package sizes for integration into compact devices. There is also a focus on developing LEDs with specific, narrow wavelength peaks for advanced sensing applications (like gas sensing) and improving the speed of modulation for high-bandwidth optical communication (Li-Fi). The drive for environmental sustainability continues to push for broader adoption of halogen-free and other green manufacturing standards.