IR LED 735nm Specification Sheet - Dimensions 2.8x3.5x0.65mm - Voltage 2.2V - Power 0.4W - English Technical Document

1. Product Overview

This document provides detailed specifications for an infrared light-emitting diode (LED) utilizing a PLCC-2 surface-mount package. The device is engineered for applications requiring near-infrared radiation, particularly in controlled agricultural and horticultural environments.

1.1 Product Positioning and Core Advantages

The LED is positioned as a reliable source of 735nm infrared light, a wavelength often utilized in plant physiology studies and growth stimulation. Its core advantages stem from the compact PLCC-2 package, which offers a wide 120-degree viewing angle, compatibility with standard SMT assembly processes, and adherence to RoHS environmental standards. The moisture sensitivity level is rated at Level 3, indicating standard handling precautions are required.

1.2 Target Market

The primary target markets include professional horticulture (e.g., flower production, tissue culture labs, vertical farms/plant factories), and general electronics where infrared emitters are needed for sensing or signaling purposes.

2. In-Depth Technical Parameter Analysis

The electrical and optical characteristics define the operational envelope and performance expectations of the device.

2.1 Photometric and Radiometric Characteristics

At a forward current (I_F) of 150mA and a junction temperature (T_s) of 25°C, the key parameters are:

• Peak Wavelength (λ_p): 735nm (typical), with a range from 730nm to 740nm. This places the emission firmly in the near-infrared spectrum.
• Total Radiant Flux (Φ_e): 112mW (typical), ranging from 90mW to 140mW. This measures the total optical power output.
• Viewing Angle (2θ_1/2): 120 degrees (typical), providing a broad emission pattern suitable for area illumination.

2.2 Electrical Characteristics

• Forward Voltage (V_F): 2.2V (typical) at I_F=150mA, within a range of 1.8V to 2.6V. This parameter is crucial for driver circuit design.
• Reverse Current (I_R): Less than 10µA at a reverse voltage (V_R) of 5V, indicating good diode integrity.

2.3 Thermal and Reliability Characteristics

• Thermal Resistance (R_θJ-S): 15°C/W (typical) from junction to solder point. This value is critical for thermal management to prevent overheating.
• Absolute Maximum Ratings: These define the limits beyond which permanent damage may occur.
  • Power Dissipation (P_D): 0.4W
  • Continuous Forward Current (I_F): 150mA
  • Peak Forward Current (I_FP): 200mA (at 1/10 duty cycle, 0.1ms pulse width)
  • Reverse Voltage (V_R): 5V
  • Electrostatic Discharge (ESD) Human Body Model (HBM): 2000V (with over 90% yield, but protection during handling is advised)
  • Operating Temperature (T_OPR): -40°C to +85°C
  • Storage Temperature (T_STG): -40°C to +100°C
  • Maximum Junction Temperature (T_J): 115°C

3. Binning System Explanation

While a formal binning code is not explicitly provided in the document, the product parameters are guaranteed within specified minimum, typical, and maximum values. This constitutes an implicit electrical and optical binning system. Key parameters subject to this variance include forward voltage (V_F), peak wavelength (λ_p), and total radiant flux (Φ_e). Designers should account for these tolerances: ±0.1V for V_F, ±2nm for λ_p, and ±10% for Φ_e. For applications requiring tight consistency, selection or testing of individual units may be necessary.

4. Performance Curve Analysis

The typical characteristic curves provide insight into device behavior under varying conditions.

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

The curve shows a non-linear relationship, typical for diodes. The forward voltage increases with current, starting around 1.65V at low currents and approaching 1.9V at the maximum rated 150mA. This curve is essential for determining the voltage drop across the LED in operation.

4.2 Relative Radiant Power vs. Forward Current

This graph demonstrates that the optical output is relatively linear with current up to the maximum rating. However, efficiency may decrease at higher currents due to increased junction temperature.

4.3 Relative Radiant Power vs. Solder Point Temperature

The output power decreases as the solder point temperature (T_s) increases. This thermal quenching effect is a fundamental property of LEDs and underscores the importance of effective heat sinking to maintain consistent light output.

4.4 Forward Current vs. Solder Point Temperature

This curve illustrates the permissible forward current derating as ambient temperature rises. To keep the junction temperature within safe limits, the maximum allowable continuous current must be reduced in high-temperature environments.

4.5 Spectral Distribution

The spectrum plot confirms a dominant peak at approximately 735nm with a typical full width at half maximum (FWHM) common to infrared LEDs. The emission is monochromatic enough for applications targeting specific photoreceptor responses in plants.

5. Mechanical and Packaging Information

5.1 Physical Dimensions

The device uses a PLCC-2 (Plastic Leaded Chip Carrier) package. Key dimensions are (all in millimeters, tolerance ±0.2mm unless noted):

• Overall Length: 3.5 mm
• Overall Width: 2.8 mm
• Overall Height: 0.65 mm
• Lead dimensions and pad spacing are as per the detailed drawings in the specification.

5.2 Pad Design and Polarity Identification

The bottom view shows two solder pads. The polarity is clearly marked; the pad associated with the anode (+) is typically larger or indicated in the footprint diagram. Correct orientation during placement is critical for functionality.

5.3 Recommended Soldering Land Pattern

A suggested PCB footprint (soldering pattern) is provided to ensure reliable solder fillets and mechanical stability after reflow. Following this pattern helps achieve proper thermal and electrical connection.

6. Soldering and Assembly Guidelines

6.1 SMT Reflow Soldering Process

The device is suitable for standard lead-free reflow soldering processes. A typical reflow profile with a peak temperature not exceeding 260°C is recommended. The specific time above liquidus should be controlled according to industry standards (e.g., IPC/JEDEC J-STD-020) to prevent package damage.

6.2 Manual Soldering and Rework

If manual soldering is necessary, use a temperature-controlled soldering iron with a tip temperature below 350°C. The contact time should be minimized (less than 3 seconds) to avoid excessive heat transfer to the LED chip. For rework, local heating is preferred over reheating the entire board.

6.3 Critical Cautions

• ESD Protection: The device is sensitive to electrostatic discharge. Use ESD-safe practices during all handling and assembly stages.
• Moisture Sensitivity: As an MSL Level 3 component, the product must be used within 168 hours after the dry bag is opened, unless baked according to standard procedures.
• Mechanical Stress: Avoid applying direct mechanical force to the lens or body of the package.
• Cleaning: If cleaning is required after soldering, use compatible solvents that do not damage the plastic package or lens.

7. Packaging and Ordering Information

7.1 Standard Packaging

The product is supplied on tape and reel for automated pick-and-place assembly. The carrier tape width, pocket dimensions, and reel size (e.g., 7-inch or 13-inch reel) conform to EIA standard specifications to ensure compatibility with SMT equipment.

7.2 Moisture-Resistant Bagging

The reels are sealed in aluminum moisture barrier bags with desiccant and a humidity indicator card to maintain dryness during storage and transport, per the MSL Level 3 requirement.

7.3 Outer Carton

Multiple reels are packed in a sturdy cardboard box for shipment, providing protection against physical damage.

8. Application Recommendations

8.1 Typical Application Scenarios

• Plant Growth and Horticulture: The 735nm wavelength can influence plant photomorphogenesis, potentially promoting stem elongation or flowering in certain species when used in combination with other light spectra.
• Biomedical and Scientific Equipment: Used as a light source in spectroscopy, particle sensing, or medical devices requiring non-visible illumination.
• General Infrared Illumination: For night-vision systems, surveillance cameras, or proximity sensors where visible light is undesirable.

8.2 Design Considerations

• Current Driving: Use a constant current driver for stable optical output. The forward voltage variation must be considered when designing the driver circuit.
• Thermal Management: Ensure the PCB has adequate thermal relief and, if necessary, use a heatsink to maintain the solder point temperature as low as possible, maximizing light output and longevity.
• Optical Design: The 120-degree viewing angle provides wide coverage. For focused beams, secondary optics (lenses) may be required.

9. Technical Comparison with Similar Products

Compared to generic infrared LEDs in different packages (e.g., 5mm through-hole or smaller chip-scale packages), this PLCC-2 device offers a balance of ease of handling for SMT assembly, good thermal path via its leads, and a standardized footprint. Its typical radiant flux of 112mW at 150mA is competitive for its package size. The primary differentiator is the combination of a specific 735nm wavelength, a robust package suitable for automated assembly, and a well-defined thermal characteristic.

10. Frequently Asked Questions (FAQs)

10.1 What is the main purpose of this LED?

This LED is primarily designed to emit infrared light at 735nm, making it suitable for applications in controlled environment agriculture and general infrared sensing/illumination where this specific wavelength is beneficial.

10.2 Can I drive it with a constant voltage source?

It is not recommended. LEDs are current-driven devices. A constant voltage source with only a series resistor can be used for simple setups, but a dedicated constant current driver is superior for maintaining consistent performance over temperature and unit-to-unit variations.

10.3 How critical is thermal management?

Very critical. Excessive junction temperature will reduce light output efficiency, shift the wavelength slightly, and significantly shorten the operational lifetime. The provided thermal resistance value (15°C/W) should be used to calculate the expected temperature rise under your operating conditions.

10.4 Is this LED eye-safe?

Infrared radiation is invisible to the human eye, but it can still pose a hazard at high power densities. Always follow appropriate laser and LED safety standards for your application, which may include enclosure design or output power limitations.

11. Practical Use Cases

11.1 Case Study: Supplemental Lighting in a Vertical Farm

In a multi-layer vertical farming system, arrays of these LEDs could be integrated into growth racks to provide a specific far-red (735nm) light treatment during the final stage of lettuce cultivation. This treatment, when timed correctly, can influence plant morphology and potentially enhance certain qualities without increasing visible light intensity, saving energy.

11.2 Case Study: Proximity Sensor in an Appliance

The LED can be paired with a photodetector to create a simple proximity or object detection sensor in a home appliance (e.g., automatic soap dispenser). Its 735nm wavelength is less likely to cause interference from ambient visible light compared to red LEDs, improving signal-to-noise ratio.

12. Principle Introduction

Light-emitting diodes are semiconductor devices that emit light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons and holes recombine, releasing energy in the form of photons. The wavelength (color) of the emitted light is determined by the bandgap energy of the semiconductor materials used. For this infrared LED, materials like aluminum gallium arsenide (AlGaAs) are commonly employed to achieve emission in the 730-740nm range. The PLCC package houses the semiconductor chip, provides electrical connections via leads, and includes a plastic lens that shapes the light output beam.

13. Development Trends in LED Technology

The broader LED industry continues to evolve in several directions relevant to such components:

• Increased Efficiency: Ongoing research aims to improve the wall-plug efficiency (electrical-to-optical power conversion) of all LEDs, including infrared types, reducing energy consumption for the same optical output.
• Enhanced Thermal Performance: New package designs and materials are being developed to lower thermal resistance, allowing for higher drive currents or more compact designs without overheating.
• Precision Wavelength Control: Advances in epitaxial growth techniques enable tighter control over emission wavelengths, which is crucial for scientific and specialized agricultural applications where specific photoreactions are targeted.
• Integration and Smart Systems: Trends point towards LEDs being integrated with drivers, sensors, and communication interfaces into \"smart\" modules for IoT-enabled agricultural or industrial systems.
• Sustainability: There is a growing emphasis on using more environmentally friendly materials in LED packaging and improving recyclability.

This specification document details a component that fits within these ongoing trends, offering a standardized, reliable infrared source for current technological needs.