5mm Infrared LED SIR383C Datasheet - 5mm Package - 1.6V Forward Voltage - 875nm Wavelength - 150mW Power - English Technical Document

1. Product Overview

The SIR383C is a high-intensity 5mm Infrared (IR) Emitting Diode. It is molded in a water-clear plastic package and is designed to emit light at a peak wavelength of 875 nanometers (nm). This device is spectrally matched with common silicon phototransistors, photodiodes, and infrared receiver modules, making it an ideal source for various IR sensing and transmission applications.

Key advantages of this component include its high reliability, high radiant intensity output, and low forward voltage requirement. It is constructed using lead-free (Pb-Free) materials and complies with relevant environmental regulations including RoHS, EU REACH, and halogen-free standards (Br < 900ppm, Cl < 900ppm, Br+Cl < 1500ppm). The standard 2.54mm lead spacing facilitates easy integration into standard printed circuit boards (PCBs).

2. Technical Parameter Deep Dive

2.1 Absolute Maximum Ratings

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

• Continuous Forward Current (I_F): 100 mA
• Peak Forward Current (I_FP): 1.0 A (Pulse Width ≤ 100μs, Duty Cycle ≤ 1%)
• Reverse Voltage (V_R): 5 V
• Operating Temperature (T_opr): -40°C to +85°C
• Storage Temperature (T_stg): -40°C to +100°C
• Soldering Temperature (T_sol): 260°C (for ≤ 5 seconds)
• Power Dissipation (P_d): 150 mW (at or below 25°C free air temperature)

2.2 Electro-Optical Characteristics (T_a = 25°C)

These are the typical performance parameters under specified test conditions.

• Radiant Intensity (I_e): Typically 20 mW/sr at I_F = 20mA. Under pulsed conditions (I_F = 100mA, Pulse ≤ 100μs, Duty ≤ 1%), it can reach 95 mW/sr, and up to 950 mW/sr at I_F = 1A with the same pulse constraints.
• Peak Wavelength (λ_p): 875 nm (at I_F = 20mA)
• Spectral Bandwidth (Δλ): 80 nm (at I_F = 20mA)
• Forward Voltage (V_F): 1.3 V (Typical), 1.6 V (Maximum) at I_F = 20mA
• Reverse Current (I_R): 10 μA (Maximum) at V_R = 5V
• View Angle (2θ_1/2): 20 degrees (at I_F = 20mA)

Note: Measurement uncertainties are ±0.1V for V_F, ±10% for I_e, and ±1.0nm for λ_p.

3. Performance Curve Analysis

The datasheet provides several characteristic curves essential for design engineers.

3.1 Forward Current vs. Ambient Temperature

This derating curve shows how the maximum permissible continuous forward current decreases as the ambient temperature increases above 25°C. Proper heat management requires consulting this graph to prevent overheating and ensure long-term reliability.

3.2 Spectral Distribution

The graph illustrates the relative radiant power output across the wavelength spectrum, centered around the 875nm peak. The 80nm bandwidth indicates the range of wavelengths emitted, which is important for matching with the sensitivity curve of the receiving sensor.

3.3 Peak Emission Wavelength vs. Ambient Temperature

This curve demonstrates the shift in the peak wavelength (λ_p) with changes in the ambient temperature. Understanding this thermal drift is critical for applications requiring precise wavelength alignment.

3.4 Forward Current vs. Forward Voltage (I-V Curve)

The I-V curve is fundamental for circuit design, showing the nonlinear relationship between the current through the LED and the voltage across it. It helps in selecting appropriate current-limiting resistors and power supply requirements.

3.5 Radiant Intensity vs. Forward Current

This graph shows the optical output (radiant intensity) as a function of the drive current. It is typically sub-linear at higher currents due to thermal and efficiency effects, highlighting the importance of driving the LED within its optimal range.

3.6 Relative Radiant Intensity vs. Angular Displacement

This polar plot defines the spatial emission pattern or view angle of the LED. The 20-degree viewing angle indicates a relatively focused beam, which is suitable for directed IR applications.

4. Mechanical and Packaging Information

4.1 Package Dimension

The SIR383C is housed in a standard 5mm round LED package. Key dimensions include a body diameter of 5.0mm, a typical lead spacing of 2.54mm, and an overall length. The cathode is typically identified by a flat side on the LED lens and/or a shorter lead. All dimensions have a tolerance of ±0.25mm unless otherwise specified. Engineers must refer to the detailed mechanical drawing in the datasheet for exact placement and footprint design.

5. Soldering and Assembly Guidelines

Proper handling is crucial to maintain device integrity and performance.

5.1 Lead Forming

• Bending should occur at least 3mm from the base of the epoxy bulb.
• Form leads before soldering and avoid stressing the package.
• Cut leads at room temperature, not when hot.
• Ensure PCB holes align perfectly with LED leads to avoid mounting stress.

5.2 Storage

• Store at ≤ 30°C and ≤ 70% Relative Humidity (RH). Shelf life is 3 months under these conditions.
• For longer storage (up to 1 year), use a sealed container with a nitrogen atmosphere and desiccant.
• Avoid rapid temperature changes in humid environments to prevent condensation.

5.3 Soldering

Maintain a minimum distance of 3mm from the solder joint to the epoxy bulb.

• Hand Soldering: Iron tip temperature ≤ 300°C (for 30W max iron), soldering time ≤ 3 seconds.
• Wave/DIP Soldering: Preheat ≤ 100°C (max 60 sec), solder bath ≤ 260°C for ≤ 5 seconds.
• Avoid stress on leads during and immediately after soldering while the device is hot.
• Do not perform dip/hand soldering more than once.
• Allow the LED to cool gradually to room temperature, protecting it from shock or vibration during cooling.

5.4 Cleaning

• If necessary, clean only with isopropyl alcohol at room temperature for ≤ 1 minute. Air dry.
• Avoid ultrasonic cleaning. If absolutely required, pre-qualify the process parameters to ensure no damage occurs.

5.5 Heat Management

Thermal management must be considered during the application design phase. The operating current should be derated according to the Forward Current vs. Ambient Temperature curve to prevent excessive junction temperature, which can degrade performance and lifespan.

6. Packaging and Ordering Information

6.1 Label Specification

The product label includes information such as Customer Part Number (CPN), Product Number (P/N), Packing Quantity (QTY), and various performance ranks (CAT for intensity, HUE for wavelength, REF for voltage), along with Lot Number and date codes.

6.2 Packing Quantity

The standard packing is 500 pieces per bag, with 5 bags per inner box. A standard carton contains 10 inner boxes, totaling 5000 pieces.

7. Application Suggestions

7.1 Typical Application Scenarios

• Infrared Remote Control Units: Its high radiant intensity, especially under pulsed operation, makes it suitable for long-range or high-power remote controls.
• Smoke Detectors: Used in photoelectric smoke detectors where an IR beam is scattered by smoke particles onto a receiver.
• Infrared Applied Systems: General purpose IR transmission for data links, proximity sensors, object counters, and industrial automation.

7.2 Design Considerations

• Current Driving: Use a constant current source or a current-limiting resistor in series with the LED. Refer to the I-V and derating curves.
• Pulsing for Higher Output: For applications requiring very high instantaneous intensity (e.g., long-range transmission), use the pulsed driving specifications (I_FP up to 1A with strict duty cycle limits).
• Spectral Matching: Ensure the receiver (phototransistor, photodiode, or IR module) has peak sensitivity around 875nm for optimal signal strength.
• Optical Design: The 20-degree viewing angle may require lenses or reflectors to achieve the desired beam pattern.
• PCB Layout: Follow the mechanical dimensions precisely and adhere to the 3mm minimum solder-to-body distance rule.

8. Technical Comparison and Differentiation

Compared to generic 5mm IR LEDs, the SIR383C offers a balanced combination of features:

• High Intensity: Its typical radiant intensity of 20 mW/sr at 20mA is competitive for standard 5mm packages.
• Precise Wavelength: The 875nm peak is a common standard, ensuring wide compatibility with receivers.
• Robust Specifications: Clearly defined pulsed operation ratings (up to 1A) provide design flexibility for high-burst applications.
• Comprehensive Compliance: RoHS, REACH, and Halogen-Free compliance future-proofs designs for global markets.
• Detailed Application Notes: The datasheet provides extensive guidance on handling, soldering, and storage, which is crucial for manufacturing yield and product reliability.

9. Frequently Asked Questions (FAQs)

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

The Continuous Forward Current (100mA) is the maximum DC current the LED can handle indefinitely without damage, considering thermal limits. The Peak Forward Current (1A) is a much higher current allowed only for very short pulses (≤100μs) at a low duty cycle (≤1%). This allows for brief, high-intensity bursts of light without overheating the LED die.

9.2 How do I identify the cathode (negative lead)?

The cathode is typically indicated by two features: 1) A flat side on the rim of the round LED lens, and 2) The cathode lead is usually shorter than the anode lead. Always verify polarity before soldering to avoid reverse bias.

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

No, you should not connect it directly. The LED's forward voltage is around 1.3-1.6V. Connecting it directly to a higher voltage source without a current-limiting resistor will cause excessive current to flow, potentially destroying the LED instantly. Always use a series resistor calculated as R = (V_supply - V_F) / I_F.

9.4 Why is the storage condition limited to 3 months?

The plastic package can absorb moisture from the air. During subsequent high-temperature processes like soldering, this trapped moisture can rapidly expand, causing internal delamination or cracking ("popcorning"). The 3-month limit assumes standard factory floor conditions. For longer storage, the dry-bag (nitrogen with desiccant) method is prescribed to prevent moisture absorption.

10. Practical Design Case

Scenario: Designing a Long-Range IR Remote Control Transmitter.

Goal: Achieve a range of over 30 meters in a typical living room environment.

Design Steps:

1. Drive Method Selection: To maximize range, we need high instantaneous optical power. Therefore, we will use pulsed driving at the maximum rated I_FP of 1A.
2. Pulse Parameters: Set the pulse width to 100μs and the duty cycle to 1% (e.g., 100μs ON, 9900μs OFF). This ensures we stay within the Absolute Maximum Ratings.
3. Circuit Design: A simple transistor switch (e.g., NPN or N-channel MOSFET) controlled by a microcontroller GPIO pin can be used. A small base/gate resistor limits the control current. A series resistor may still be needed between the power supply and the LED to set the exact 1A pulse current, considering the transistor's saturation voltage.
4. Power Supply: The supply voltage must be high enough to overcome V_F (≈1.5V at high current) plus the voltage drop across the transistor and any series resistor. A 5V supply is typically sufficient.
5. Modulation: The IR pulses should be modulated at a carrier frequency (e.g., 38kHz) compatible with the intended receiver. This is done by turning the 1A pulses on and off at the 38kHz rate within the 100μs envelope.
6. Thermal Consideration: Although the duty cycle is very low, verify that the average power (P_avg = V_F * I_{F_avg}) is within the 150mW rating. With 1A pulses at 1% duty, I_{F_avg} = 10mA. P_avg ≈ 1.5V * 0.01A = 15mW, which is well within limits.

This approach leverages the LED's pulsed capability to achieve significantly higher range than a continuous 20mA drive would allow.

11. 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 specific wavelength of the emitted light (e.g., 875nm) is determined by the energy bandgap of the semiconductor material used, which in this case is Gallium Aluminum Arsenide (GaAlAs). The water-clear epoxy lens does not filter the IR light, allowing for high transmission efficiency. The radiant intensity is a measure of the optical power emitted per unit solid angle, indicating how focused and powerful the emitted beam is.

12. Development Trends

The field of infrared LEDs continues to evolve. General trends observable in the industry include:

• Increased Efficiency: Development of new semiconductor materials and chip structures (e.g., flip-chip, thin-film) to achieve higher radiant intensity and wall-plug efficiency (optical power out / electrical power in) from the same or smaller package sizes.
• Miniaturization: Demand for smaller package footprints (e.g., 0402, 0603 SMD) to enable more compact electronic devices, especially in consumer electronics and wearables.
• Enhanced Reliability: Improvements in packaging materials and processes to withstand higher soldering temperatures (compatible with lead-free requirements), harsher environmental conditions, and longer operational lifetimes.
• Integrated Solutions: Growth of combined emitter-sensor modules and application-specific integrated circuits (ASICs) that include drivers, modulators, and logic, simplifying system design for end-users.
• Wavelength Diversification: Availability of IR LEDs at various peak wavelengths (e.g., 850nm, 940nm, 1050nm) to suit different applications, such as avoiding interference with ambient light (940nm is less visible) or matching specific sensor sensitivities.