3.0mm Infrared LED IR204C-A Datasheet - 3mm T-1 Package - 940nm Peak Wavelength - 100mA Forward Current - English Technical Document

1. Product Overview

The IR204C-A is a high-intensity infrared emitting diode housed in a standard 3mm (T-1) water-clear plastic package. Its primary function is to emit infrared light at a peak wavelength of 940nm, making it spectrally matched with common silicon phototransistors, photodiodes, and infrared receiver modules. This device is designed for applications requiring reliable and efficient infrared transmission.

1.1 Core Advantages

• High Radiant Intensity: Delivers strong optical output, suitable for medium to long-range applications.
• High Reliability: Engineered for stable and long-term performance.
• Low Forward Voltage: Typically 1.5V at 20mA, contributing to energy-efficient operation.
• Environmental Compliance: The product is Pb-free, compliant with EU REACH, and meets halogen-free standards (Br < 900ppm, Cl < 900ppm, Br+Cl < 1500ppm).
• Standard Package: The familiar T-1 (3mm) form factor with 2.54mm lead spacing ensures easy integration into existing designs and prototyping boards.

1.2 Target Applications

• Infrared remote control units with high power requirements.
• Free-air optical data transmission systems.
• Smoke detection sensors.
• General infrared sensing and barrier systems.
• Industrial automation and object detection.

2. In-Depth Technical Parameter Analysis

This section provides a detailed, objective interpretation of the key electrical and optical parameters specified in the datasheet. Understanding these limits and typical values is crucial for robust circuit design.

2.1 Absolute Maximum Ratings

These are stress limits that must not be exceeded under any conditions, even momentarily. Operation beyond these ratings may cause permanent damage.

• Continuous Forward Current (I_F): 100 mA. The LED can be operated continuously at this current level, provided the power dissipation and temperature limits are respected.
• Peak Forward Current (I_FP): 1.0 A. This high current is permissible only under pulsed conditions (pulse width ≤ 100μs, duty cycle ≤ 1%). This is useful for achieving very high instantaneous radiant output in burst-mode applications like long-range remote controls.
• Reverse Voltage (V_R): 5 V. The LED has limited reverse voltage tolerance. Care must be taken in circuit design to prevent reverse biasing beyond this limit, which could be caused by inductive loads or improper power sequencing.
• Power Dissipation (P_d): 150 mW at or below 25°C free air temperature. This rating decreases as ambient temperature increases. The actual operating current must be derated based on the junction temperature to stay within safe limits.
• Soldering Temperature (T_sol): 260°C for a maximum of 5 seconds. This defines the reflow soldering profile constraints.

2.2 Electro-Optical Characteristics

These parameters define the device's performance under normal operating conditions (Ta=25°C).

• Radiant Intensity (I_e): This is the primary measure of optical output power per solid angle (mW/sr).
  • At I_F = 20mA (DC): Typical value is 7.8 mW/sr, with a minimum of 4.0 mW/sr.
  • At I_F = 100mA (Pulsed): Typical radiant intensity rises significantly.
  • At I_F = 1A (Pulsed): Can deliver a typical output of 390 mW/sr, showcasing its capability for high-power pulsed operation.
• Peak Wavelength (λ_p): 940 nm (typical). This wavelength is ideal as it aligns well with the peak sensitivity of silicon-based photodetectors while being largely invisible to the human eye and having good atmospheric transmission.
• Spectral Bandwidth (Δλ): Approximately 45 nm (typical). This defines the spectral width of the emitted light at half its maximum intensity (FWHM).
• Forward Voltage (V_F):
  • At 20mA: 1.5V typical, 1.2V min, crucial for calculating series resistor values.
  • At 100mA (pulsed): 1.4V typical, 1.8V max. V_F increases with current due to diode resistance.
  • At 1A (pulsed): 2.6V typical, 4.0V max, showing significant increase under high-current pulse conditions.
• Viewing Angle (2θ_1/2): 40 degrees (typical). This is the full angle at which the radiant intensity drops to half of its on-axis value. A 40° angle provides a good balance between beam concentration and coverage.

3. Binning System Explanation

The datasheet includes a binning table for radiant intensity, which is a common practice to categorize LEDs based on measured performance.

3.1 Radiant Intensity Binning

Under the condition I_F = 20mA, the LEDs are sorted into bins (K, L, M, N) based on their measured radiant intensity.

• Bin K: 4.0 - 6.4 mW/sr
• Bin L: 5.6 - 8.9 mW/sr
• Bin M: 7.8 - 12.5 mW/sr
• Bin N: 11.0 - 17.6 mW/sr

Design Implication: For applications requiring consistent optical signal strength (e.g., remote controls with a defined range), specifying a tighter bin (like a single bin) or a higher minimum bin ensures more uniform performance across production units. The bin code is typically indicated in the ordering information or on the product label.

4. Performance Curve Analysis

The typical characteristic curves provide valuable insights into the device's behavior under varying conditions.

4.1 Forward Current vs. Forward Voltage (Fig.4)

This IV curve shows the exponential relationship. The curve will shift with temperature; forward voltage typically decreases as junction temperature increases for a given current.

4.2 Relative Intensity vs. Ambient Temperature (Fig.7)

This graph is critical for thermal management. The radiant output of an LED decreases as its junction temperature rises. The curve quantifies this derating, informing designers that higher ambient temperatures or inadequate heat sinking will result in lower optical output. This must be accounted for in systems designed to operate over the full -40°C to +85°C range.

4.3 Spectral Distribution & Peak Wavelength vs. Temperature (Fig.2 & Fig.3)

Fig.2 shows the typical emission spectrum centered at 940nm. Fig.3 illustrates how the peak wavelength shifts with temperature. Infrared LEDs typically exhibit a positive temperature coefficient for wavelength (i.e., λ_p increases with temperature). This shift is important in applications where the detector has a narrow spectral response.

4.4 Angular Radiation Pattern (Fig.6)

This polar plot depicts the relative radiant intensity as a function of angular displacement from the central axis. The 40° viewing angle is confirmed here. The pattern is generally Lambertian or near-Lambertian for this package type, meaning intensity is approximately proportional to the cosine of the viewing angle.

5. Mechanical and Package Information

5.1 Package Dimensions

The device uses a standard T-1 (3mm diameter) round package. Key dimensional notes from the datasheet include:

• All dimensions are in millimeters (mm).
• Standard tolerances are ±0.25mm unless otherwise specified.
• Lead spacing is 2.54mm (0.1 inches), compatible with standard perforated boards and many sockets.

A detailed dimensioned drawing would typically be included, showing body diameter, lens shape, lead length and diameter, and seating plane.

5.2 Polarity Identification

For a standard T-1 LED, the cathode is typically identified by a flat spot on the plastic lens rim and/or by the shorter lead. The datasheet should be consulted for the specific marking of this part.

6. Soldering and Assembly Guidelines

• Reflow Soldering: The maximum soldering temperature is 260°C, and the time at or above this temperature must not exceed 5 seconds. A standard lead-free reflow profile is applicable.
• Hand Soldering: If hand soldering is necessary, a temperature-controlled iron should be used, and the soldering time per lead should be minimized (typically < 3 seconds at 350°C) to prevent thermal damage to the plastic package and the semiconductor die.
• Storage Conditions: The storage temperature range is -40°C to +85°C. Components should be kept in their original moisture-barrier bags until use to prevent moisture absorption, which can cause \"popcorning\" during reflow.

7. Packaging and Ordering Information

7.1 Packing Specifications

• Standard packing: 200 to 1000 pieces per bag.
• 5 bags are packed into 1 box.
• 10 boxes are packed into 1 carton.

7.2 Label Information

The product label contains key traceability and specification data:

• CPN (Customer Part Number)
• P/N (Manufacturer Part Number: IR204C-A)
• QTY (Packing Quantity)
• Ranks/Bin Codes (e.g., for Radiant Intensity)
• HUE (Peak Wavelength information)
• LOT No. (Traceable lot number)

8. Application Design Recommendations

8.1 Driving Circuit Design

The LED must be driven with a current-limiting element, typically a resistor in series with a voltage source. The resistor value (R_s) is calculated as: R_s = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet for the chosen operating current to ensure the current does not exceed the desired value. For example, for a 5V supply and a target I_F of 20mA using the max V_F of 1.5V: R_s = (5 - 1.5) / 0.02 = 175 Ω. A standard 180 Ω resistor would be suitable. For pulsed operation at high currents, a transistor switch (BJT or MOSFET) is required.

8.2 Thermal Considerations

While the T-1 package has limited thermal dissipation capability, at continuous currents up to 100mA, ensuring adequate airflow or considering the power dissipation (P_d = V_F * I_F) is important. If operated continuously near the maximum current in a high ambient temperature, the junction temperature may rise, reducing output and potentially affecting longevity.

8.3 Optical Design

The water-clear lens is suitable for use with external lenses or reflectors to collimate or shape the beam for specific applications like long-range transmission. The 940nm wavelength is well-transmitted by many common plastics used in lenses and windows.

9. Technical Comparison and Differentiation

The IR204C-A positions itself with key differentiators:

• High Pulsed Power Capability: The 1A peak current rating allows for very high instantaneous optical output, an advantage over LEDs rated only for lower pulsed currents.
• Standardized Package with Performance: It offers higher radiant intensity in the common, easy-to-use T-1 package compared to many basic infrared LEDs.
• Environmental Compliance: Full compliance with modern environmental regulations (RoHS, REACH, Halogen-Free) is a significant advantage for products targeting global markets.
• Spectral Matching: The explicit mention of being spectrally matched to common detectors simplifies the selection process for designers building complete optical systems.

10. Frequently Asked Questions (Based on Technical Parameters)

1. Q: Can I drive this LED directly from a 3.3V microcontroller pin?
   A: No. A microcontroller pin cannot source 20mA continuously safely, and it lacks current limiting. You must use a series resistor and a transistor switch. The LED's V_F (1.5V) is less than 3.3V, so it is compatible voltage-wise, but current must be controlled externally.
2. Q: What is the difference between Radiant Intensity (mW/sr) and Radiant Power (mW)?
   A: Radiant Intensity is angular density—power per unit solid angle. Radiant Power (or Flux) is the total power emitted in all directions. To find total power, you would integrate the intensity over the entire emission pattern. The datasheet provides intensity, which is more useful for calculating irradiance at a distance in a given direction.
3. Q: Why is the peak wavelength 940nm preferred over 850nm?
   A: 940nm is less visible to the human eye (darker red glow) than 850nm, making it less distracting in consumer devices. Both are well-detected by silicon, but 940nm may have slightly lower ambient light interference from some sources like sunlight and incandescent bulbs, which have strong emissions in the 850nm region.
4. Q: How do I select the correct bin?
   A: If your application has a minimum required signal strength at the receiver, use the minimum value of a bin to ensure all parts meet it. For example, if you need at least 6 mW/sr, specify Bin L or higher. For cost-sensitive applications where some variation is acceptable, a wider bin or the default offering may be sufficient.

11. Practical Design and Usage Examples

11.1 Long-Range Infrared Remote Control

Scenario: Designing a remote control that must work reliably at a distance of 15 meters in a moderately lit living room.
Implementation: Use the LED in pulsed mode. Drive it with short (e.g., 50μs), high-current pulses (e.g., 500mA) using a MOSFET switch controlled by an encoder IC. This delivers high peak radiant intensity (refer to the 1A pulsed data) for long-range transmission while keeping average power low. A simple plastic lens can be added to collimate the beam further. The 940nm wavelength minimizes visible glow.

11.2 Proximity or Object Detection Sensor

Scenario: Creating a non-contact object detection system with a range of 10-50 cm.
Implementation: Pair the IR204C-A with a matched phototransistor. Drive the LED with a moderate continuous current (e.g., 50mA) using a constant current source for a stable light output. Modulate the LED current at a specific frequency (e.g., 38kHz) and use a tuned receiver on the phototransistor side. This modulation technique makes the system highly immune to ambient light fluctuations (like from sunlight or room lights), greatly improving signal-to-noise ratio and reliability.

12. Operating Principle

An Infrared Light Emitting Diode (IR LED) is a semiconductor p-n junction diode. When forward biased, electrons from the n-region recombine with holes from the p-region in the active region. For an infrared LED like the IR204C-A, the energy bandgap of the semiconductor material (typically Gallium Aluminum Arsenide - GaAlAs as indicated) is such that the energy released during this recombination process corresponds to a photon in the infrared spectrum (around 940nm wavelength). The water-clear epoxy package acts as a lens, shaping the emitted light into the characteristic viewing angle. The intensity of the emitted light is directly proportional to the forward current flowing through the diode, up to the device's physical limits.

13. Technology Trends

Infrared LED technology continues to evolve alongside visible LED technology. Key trends influencing devices like the IR204C-A include:

• Increased Efficiency: Ongoing material science research aims to improve the wall-plug efficiency (optical power out / electrical power in) of IR LEDs, allowing for higher output at lower drive currents or reduced heat generation.
• Higher Power Density: Development of chip-scale packages and improved thermal management materials enables IR LEDs to handle higher continuous and pulsed currents in smaller form factors.
• Integration: There is a trend towards integrating the IR emitter with a driver IC, photodetector, or even a microcontroller into single modules for specific applications (e.g., proximity sensors, gesture recognition).
• Wavelength Precision and Stability: Advances in epitaxial growth techniques allow for tighter control over peak wavelength and spectral width, which is critical for applications like gas sensing or optical communications that use wavelength-division multiplexing.
• Expanding Application Space: The growth of areas like LiDAR for automotive/robotics, facial recognition, and health monitoring (e.g., pulse oximetry) drives demand for high-performance, reliable IR emitters across various wavelengths and power levels.

The IR204C-A, with its balanced specifications and standard package, represents a mature and reliable solution within this evolving technological landscape.