LTE-3223L-062A IR Emitter Datasheet - Package 5.0mm - Peak Wavelength 940nm - High Current 2A Pulse - Clear Package - English Technical Document

1. Product Overview

The LTE-3223L-062A is a high-performance infrared (IR) light-emitting diode (LED) designed for applications requiring robust optical output and reliable operation under demanding electrical conditions. This device is engineered to deliver high radiant intensity while maintaining a low forward voltage drop, making it efficient for both continuous and pulsed driving schemes. Its primary function is to emit infrared radiation at a peak wavelength of 940 nanometers, which is commonly used in remote control systems, proximity sensors, optical switches, and various industrial sensing applications. The emitter is housed in a clear, transparent package that maximizes light output and provides a wide radiation pattern.

1.1 Core Advantages and Target Market

The key advantages of this IR emitter stem from its optimized design for high-current operation. It is specifically suited for applications where high instantaneous optical power is required, such as in long-range IR data transmission or high-sensitivity detection systems. The ability to handle significant pulse currents allows for the creation of very bright, short-duration light bursts, which can improve signal-to-noise ratios in sensing applications. The wide viewing angle ensures a broad and uniform radiation field, beneficial for area illumination or sensors with less stringent alignment requirements. The clear package eliminates the filtering effect of tinted resin, resulting in higher overall radiant efficiency. The target market includes consumer electronics (e.g., TV remotes), industrial automation (e.g., object detection, counting), security systems (e.g., beam break sensors), and communication devices.

2. In-Depth Technical Parameter Analysis

This section provides a detailed, objective interpretation of the electrical and optical parameters specified in the datasheet, explaining their significance for circuit design and application performance.

2.1 Absolute Maximum Ratings

The Absolute Maximum Ratings define the stress limits beyond which permanent damage to the device may occur. These are not conditions for normal operation but are critical for understanding the device's robustness during assembly (e.g., soldering) and under fault conditions.

• Power Dissipation (150 mW): This is the maximum amount of power the package can dissipate as heat at an ambient temperature (Ta) of 25°C. Exceeding this limit risks overheating the semiconductor junction, leading to accelerated degradation or catastrophic failure. Designers must ensure the operating forward current and voltage product does not exceed this value, considering derating at higher ambient temperatures.
• Peak Forward Current (2 A @ 300pps, 10µs pulse): This rating highlights the device's capability for intense pulsed operation. It can withstand very high currents (2 Amperes) for extremely short durations (10 microseconds) at a moderate pulse repetition rate (300 pulses per second). This is crucial for applications like IR remote controls, where brief, high-power pulses are used to transmit codes.
• Continuous Forward Current (100 mA): The maximum DC current that can be passed through the LED indefinitely without exceeding the power dissipation or junction temperature limits. For reliable long-term operation, it is advisable to operate below this maximum, typically at the recommended operating current of 20mA or 50mA as shown in the characteristics.
• Reverse Voltage (5 V): IR LEDs, like most diodes, have a relatively low reverse breakdown voltage. Applying a reverse bias greater than 5V can cause a sudden increase in reverse current, potentially damaging the device. Circuit protection, such as a series resistor or a parallel protection diode, may be necessary if the LED is exposed to voltage transients or bidirectional signals.
• Operating & Storage Temperature Ranges: The device is rated for operation from -40°C to +85°C, suitable for industrial and extended commercial environments. The wider storage range (-55°C to +100°C) indicates the device's resilience when not powered.
• Lead Soldering Temperature (260°C for 5 seconds): This specifies the maximum thermal profile the leads can withstand during wave or reflow soldering, measured 1.6mm from the package body. Adhering to this is vital to prevent internal bond wire damage or package cracking.

2.2 Electro-Optical Characteristics

These parameters are measured under standard test conditions (Ta=25°C) and define the device's performance in normal operation.

• Radiant Intensity (I_E): 8.0 (Min) to 15.0 (Typ) mW/sr at I_F=20mA. Radiant intensity measures the optical power emitted per unit solid angle (steradian). The typical value of 15 mW/sr indicates a powerful emitter. The minimum value guarantees a baseline performance level for production units.
• Peak Emission Wavelength (λ_Peak): 940 nm (Typical). This is the wavelength at which the LED emits the most optical power. 940nm is in the near-infrared spectrum, invisible to the human eye but well-detected by silicon photodiodes and many CMOS/CCD sensors. It is a common standard for IR systems.
• Spectral Line Half-Width (Δλ): 50 nm (Typical). This parameter, also called Full Width at Half Maximum (FWHM), describes the bandwidth of the emitted light. A value of 50nm means the optical power is spread across wavelengths from approximately 915nm to 965nm. This is important when matching with optical filters on the detector side.
• Forward Voltage (V_F): Two values are given: 1.25V (Min) / 1.6V (Typ) at 50mA, and 1.65V (Min) / 2.1V (Typ) at 250mA. V_F increases with current due to the diode's internal resistance. The low V_F is a key feature, reducing power loss and heat generation, especially beneficial in battery-powered or high-current applications.
• Reverse Current (I_R): 100 µA (Max) at V_R=5V. This is the small leakage current that flows when the diode is reverse-biased at its maximum rated voltage. A low value is desirable.
• Viewing Angle (2θ_1/2): 30° (Typical). Defined as the full angle where the radiant intensity drops to half of its peak value (on-axis). A 30° angle provides a reasonably focused beam, offering a good balance between intensity and coverage area.

3. Performance Curve Analysis

The datasheet includes several graphs that illustrate the device's behavior under varying conditions. These curves are essential for predictive modeling and robust design.

3.1 Spectral Distribution (Fig.1)

This curve plots relative radiant intensity against wavelength. It visually confirms the peak wavelength of 940nm and the spectral half-width. The shape is typical for an AlGaAs-based IR LED, showing a relatively symmetric distribution around the peak. Designers use this to ensure compatibility with the spectral sensitivity of the intended photodetector.

3.2 Forward Current vs. Ambient Temperature (Fig.2)

This derating curve shows how the maximum allowable continuous forward current decreases as the ambient temperature increases. At 25°C, the full 100mA is permissible. As temperature rises, the power dissipation limit is reached at lower currents to prevent junction overheating. This graph is critical for designing systems that operate in elevated temperature environments, ensuring thermal reliability.

3.3 Forward Current vs. Forward Voltage (Fig.3)

The I-V characteristic curve of the diode. It is non-linear, showing the exponential relationship typical of a PN junction. The curve allows designers to determine the exact V_F for a given operating I_F, which is necessary for calculating series resistor values or driver circuit requirements. The graph shows the low V_F characteristic clearly.

3.4 Relative Radiant Intensity vs. Ambient Temperature (Fig.4) & Forward Current (Fig.5)

Figure 4 demonstrates the temperature dependence of optical output. The radiant intensity decreases as temperature increases, a common phenomenon in LEDs known as thermal droop. This must be compensated for in applications requiring stable optical output over a wide temperature range, potentially by using temperature feedback in the driver circuit. Figure 5 shows how radiant intensity increases with forward current. The relationship is generally linear at lower currents but may sub-linearly saturate at very high currents due to thermal and efficiency effects. This curve helps in selecting the drive current to achieve a desired optical output level.

3.5 Radiation Diagram (Fig.6)

This polar plot provides a detailed visualization of the spatial emission pattern. The concentric circles represent relative intensity. The plot confirms the 30° viewing angle (half-angle of 15°) and shows the beam profile is quite smooth and symmetrical, which is desirable for uniform illumination.

4. Mechanical and Packaging Information

4.1 Package Dimensions and Polarity Identification

The device uses a standard 5mm radial leaded package (often referred to as T-1¾). The anode and cathode are identified by lead length in the drawing (with the note that the final length after taping may differ). Typically, the longer lead denotes the anode (+). The package features a flange for mechanical stability during insertion and a flat side on the lens for polarity orientation. The clear, domed lens is designed to optimize light extraction and viewing angle.

4.2 Tape and Reel Specifications

For automated assembly, the components are supplied on embossed carrier tape. The detailed table on page 4 specifies all critical tape dimensions: pocket pitch (P: 12.4-13.0mm), component positioning (P1, P2, H), tape width (W3: 17.5-19.0mm), and feed hole specifications (D, P). Adhesive tape (width W1) seals the cover tape over the components. These dimensions are standardized to ensure compatibility with pick-and-place machines and reel feeders.

5. Soldering and Assembly Guidelines

While specific reflow profiles are not provided, the absolute maximum rating for lead soldering (260°C for 5 seconds at 1.6mm from the body) provides a key constraint. For wave soldering, this rating must not be exceeded. For reflow soldering, a standard profile for through-hole components with a peak temperature ≤ 260°C and time above liquidus (TAL) controlled to minimize thermal stress is recommended. The leads should be clipped and soldered without applying excessive mechanical stress to the package body. Prolonged exposure to high humidity before soldering should be avoided, and standard moisture sensitivity level (MSL) handling practices are advised, though not explicitly stated in this datasheet.

6. Packaging and Ordering Information

The packing illustration shows a standard shipping box. The label area on the datasheet's last page indicates fields for the device number (LTE-3223L-062A), bin quantity (e.g., 20K), customer name, device type, order quantity, and a quality control stamp. The device follows a logical part numbering scheme: likely indicating the series (LTE-3223), a variant code (L), and a specific bin or optical characteristic code (062A). For precise ordering, the complete part number LTE-3223L-062A must be used.

7. Application Suggestions and Design Considerations

7.1 Typical Application Circuits

Simple DC Drive: A series current-limiting resistor is mandatory. Calculate R = (V_CC - V_F) / I_F. Use the V_F from the datasheet at your chosen I_F. For example, for 20mA from a 5V supply: R = (5V - 1.6V) / 0.02A = 170Ω (use 180Ω standard value). Ensure the resistor's power rating is sufficient (P = I_F² * R).

Pulsed Drive for High Intensity: To utilize the 2A peak current capability, a transistor (BJT or MOSFET) switch is used. A small series resistor may still be needed to control current rise time or provide minor limiting. The pulse width must be kept ≤ 10µs and the duty cycle low enough to keep the average power dissipation within limits. For example, at 300pps and 10µs pulse width, the duty cycle is 0.3%, so average current is very low.

7.2 Optical Design Considerations

• Lensing: Secondary optics (plastic lenses) can be used to collimate the beam for longer range or to shape the pattern.
• Alignment: The wide viewing angle eases alignment with detectors in proximity sensing. For focused beam applications, mechanical fixtures are crucial.
• Interference: Sunlight and other IR sources (incandescent bulbs) contain 940nm radiation. Use modulated (pulsed) signals and synchronous detection in the receiver to reject ambient light noise.

7.3 Thermal Management

Although the package is small, at higher continuous currents (e.g., 50-100mA), power dissipation becomes significant (up to 150mW). Providing adequate airflow or, in extreme cases, considering the PCB as a heat sink via the leads can improve long-term reliability and maintain output stability.

8. Technical Comparison and Differentiation

The LTE-3223L-062A differentiates itself in the market of 5mm IR emitters through its combination of high pulse current capability (2A) and low forward voltage. Many comparable emitters may have similar continuous current ratings but lower peak pulse ratings. This makes it uniquely suited for applications requiring very high instantaneous brightness. The clear package offers marginally higher efficiency than diffused or tinted packages. Its 30° viewing angle is narrower than some "wide angle" variants (which can be 40-60°) but provides higher on-axis intensity, offering a trade-off between beam concentration and coverage area.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED directly from a microcontroller GPIO pin?

A: No. A typical GPIO pin can source/sink 20-50mA, which is within the continuous range, but it cannot provide the ~1.6V forward voltage drop. You must use a transistor as a switch. For the 2A pulse, a dedicated driver circuit is essential.

Q: What is the difference between Radiant Intensity (mW/sr) and Luminous Intensity (mcd)?

A: Radiant Intensity measures total optical power, while Luminous Intensity measures power as perceived by the human eye, weighted by the photopic response curve. Since this is an IR LED invisible to humans, its luminous intensity is effectively zero or not specified. Radiant Intensity is the correct metric.

Q: How do I choose a matching photodetector?

A: Select a photodiode or phototransistor with peak sensitivity around 940nm. Silicon devices typically have peak sensitivity between 800-900nm, making them a good match. Ensure the detector's active area and field of view are appropriate for your optical design.

10. Practical Application Example

Design Case: Long-Range Infrared Barrier Sensor.

Objective: Detect an object breaking a beam over a 5-meter distance.

Design: Use the LTE-3223L-062A in pulsed mode. Drive it with a MOSFET switch at 1A pulses (well below the 2A max), 10µs width, 1kHz frequency. A collimating lens is placed in front to create a narrow beam. On the receiver side, a focused lens collects light onto a matched photodiode with a narrow-bandpass optical filter centered at 940nm. The receiver circuit is tuned to the 1kHz modulation frequency, rejecting constant ambient light and low-frequency noise. The high pulse current ensures a strong signal reaches the distant detector, while the low duty cycle keeps average power low.

11. Operating Principle

The device operates on the principle of electroluminescence in a semiconductor PN junction. When forward-biased, electrons from the N-type region and holes from the P-type region are injected across the junction. These carriers recombine in the active region, releasing energy in the form of photons. The specific semiconductor materials (typically Aluminum Gallium Arsenide - AlGaAs) are chosen so that the energy bandgap corresponds to photon emission at a wavelength of 940nm, which is in the infrared spectrum. The clear epoxy package encapsulates the semiconductor chip, provides mechanical protection, and acts as a lens to shape the output beam.

12. Technology Trends

Infrared emitter technology continues to evolve alongside visible LED technology. Trends include:

Increased Power Density: Development of chip-scale packages and advanced thermal management to deliver higher optical power from smaller footprints.

Wavelength Specificity: Emitters with narrower spectral bandwidths for improved signal-to-noise ratio in spectroscopic sensing and optical communication.

Integrated Solutions: Combining the emitter, driver, and sometimes a detector or sensor into a single module (e.g., proximity sensor modules, gesture recognition chips).

High-Speed Modulation: Optimizing devices for very fast switching (nanoseconds) to support high-speed data transmission over IR, such as in IrDA-compliant communication or Li-Fi prototypes.

The LTE-3223L-062A represents a mature, high-reliability solution within this evolving landscape, particularly strong in applications demanding high pulse power.