1. Product Overview
This document details the technical specifications and application guidelines for a high-reliability surface-mount deep red LED. The device utilizes an EMC (Epoxy Molding Compound) package, offering robust performance for demanding environments. Its primary application is within the horticulture lighting sector, providing the specific light spectra required for plant physiological processes.
1.1 Core Features and Positioning
The LED's defining characteristic is its emission at a peak wavelength of 660 nanometers, situating it within the far-red spectrum. This wavelength is crucial for photosynthesis and photomorphogenesis in plants, influencing flowering, stem elongation, and fruit development. The compact 3.00mm x 3.00mm x 3.08mm footprint (3030 package) allows for high-density array designs in grow light fixtures. Key selling points include its compatibility with standard Pb-free reflow soldering processes, compliance with RoHS directives, and a Moisture Sensitivity Level (MSL) of 3, which informs handling and storage protocols prior to assembly.
1.2 Target Applications
This component is engineered explicitly for controlled-environment agriculture (CEA) and advanced horticulture. Its typical use cases include:
- Supplemental Lighting in Greenhouses: To extend the photoperiod or boost light intensity during low-light seasons.
- Vertical Farms and Plant Factories: As part of multi-spectral LED arrays in fully artificial growth environments.
- Tissue Culture Laboratories: Providing specific light qualities to regulate plantlet growth and development in sterile conditions.
- Specialized Growth Chambers: For research on plant physiology and optimized growth recipes.
2. In-Depth Technical Parameter Analysis
Understanding the absolute maximum ratings and typical operating characteristics is vital for reliable circuit design and ensuring long-term LED performance.
2.1 Absolute Maximum Ratings (Ts=25°C)
These limits must never be exceeded, even momentarily, as they define the boundary conditions for safe operation. Exceeding these values may cause permanent damage.
- Power Dissipation (PD): 1.3W. This is the maximum allowable power converted to heat at the junction. Design must ensure thermal management keeps the junction temperature well below its maximum.
- Forward Current (IF): 500mA (continuous). A pulsed current rating might be higher but is not specified here for continuous operation.
- Reverse Voltage (VR): 5V. LEDs have very low reverse breakdown voltage. Circuit protection (e.g., a diode in parallel) is essential if reverse voltage is possible.
- Electrostatic Discharge (ESD): 2000V (Human Body Model). Proper ESD handling procedures are mandatory during assembly.
- Junction Temperature (TJ): 115°C maximum. The core design constraint; all thermal design aims to keep TJ as low as possible under operating conditions.
- Operating & Storage Temperature: -40°C to +85°C / -40°C to +100°C.
2.2 Electro-Optical Characteristics (Ts=25°C, IF=350mA)
These are typical performance parameters measured under standardized test conditions.
- Peak Wavelength (λp): 660nm (Typical), with a range from 655nm to 670nm. This tight binning ensures consistent spectral output for horticultural efficacy.
- Forward Voltage (VF): 1.8V to 2.6V at 350mA. Designers must account for this variance when planning driver circuits and power supplies. The typical curve shows VF increases with current and temperature.
- Total Radiant Flux (Φe): 230mW to 530mW. This is the total optical power output in the radiant spectrum, not weighted by human eye sensitivity. Efficiency can be inferred from this value relative to the electrical input power (VF * IF).
- Viewing Angle (2θ1/2): 30 degrees (Typical). This narrow beam angle is beneficial for directing light downward onto plant canopies in focused lighting applications.
- Thermal Resistance (RθJ-S): 14°C/W (Typical). This is the junction-to-solder point resistance. A lower value indicates better heat transfer from the semiconductor die to the board. System thermal resistance (junction-to-ambient) will be higher and depends heavily on PCB design (copper area, vias) and external heatsinking.
3. Performance Curves and Graphical Analysis
The provided curves offer critical insights into the LED's behavior under varying electrical and thermal conditions.
3.1 Forward Voltage vs. Forward Current (I-V Curve)
This graph shows a non-linear relationship. The forward voltage increases logarithmically with current. At the recommended 350mA drive current, the voltage typically falls between 2.0V and 2.2V for most units. Designers use this curve to size current-limiting resistors or design constant-current drivers accurately.
3.2 Relative Intensity vs. Forward Current
The optical output is highly dependent on drive current. The curve is generally linear in the mid-range but can saturate or experience efficiency droop at very high currents due to increased heat and other semiconductor effects. Operating at or below 350mA ensures stable, efficient output.
3.3 Relative Intensity vs. Junction/Solder Point Temperature
LED efficiency decreases as temperature rises. This curve quantifies the thermal derating. For example, output may drop to 80% of its room-temperature value when the solder point reaches 80-90°C. Effective thermal management is therefore directly linked to maintaining light output and longevity.
3.4 Spectral Distribution
The spectrum plot confirms a dominant peak at ~660nm with a typical full width at half maximum (FWHM) characteristic of AlGaInP semiconductor material. There is minimal emission in other wavelengths, making it spectrally pure for targeted plant photoreceptor activation (e.g., phytochrome PFR).
3.5 Spatial Radiation Pattern
The polar diagram illustrates the 30-degree viewing angle, showing how intensity diminishes towards the edges of the beam. This pattern is important for calculating light distribution uniformity on a growth plane.
4. Mechanical Dimensions & Package Information
The physical design ensures compatibility with automated assembly and reliable solder joints.
4.1 Package Outline Drawings
The LED has a square footprint with dimensions of 3.00mm ± 0.20mm per side and a height of 3.08mm ± 0.20mm. The cathode is identified by a marked corner on the top and a larger pad/thermal pad on the bottom view. The side view shows the lens structure atop the EMC package.
4.2 Recommended Soldering Pad Layout
A land pattern design is provided to ensure a reliable solder fillet and proper thermal connection. The anode and cathode pads are specified, along with a central thermal pad (if applicable, though not explicitly shown in the excerpt, it is common for power LEDs). Following this footprint is critical for mechanical stability and heat dissipation.
5. SMT Reflow Soldering Instructions
This device is designed for surface-mount technology assembly using lead-free solder paste.
5.1 Process Guidelines
As an MSL Level 3 component, the device must be baked if the moisture barrier bag has been opened for more than 168 hours (7 days) prior to reflow. A standard lead-free reflow profile should be used, with a peak temperature not exceeding 260°C. The profile should include adequate preheat to activate flux and minimize thermal shock, followed by a controlled ramp to peak temperature and cooling.
5.2 Handling and Storage Precautions
Always handle LEDs with ESD-safe equipment and procedures. Store in original, unopened moisture barrier bags in a controlled environment. If baking is required, follow the manufacturer's recommended time and temperature (typically 125°C for 24 hours). Avoid mechanical stress on the lens. Do not clean with ultrasonic cleaners after soldering, as this may damage the package.
6. Packaging and Ordering Specifications
6.1 Tape and Reel Packaging
The product is supplied in embossed carrier tape on reels for automated pick-and-place machines. Each reel contains 2500 pieces. The carrier tape dimensions (pocket size, pitch) and reel dimensions (hub diameter, flange diameter, width) conform to standard EIA-481 guidelines to ensure compatibility with mainstream SMT equipment.
6.2 Reliability Testing
The product undergoes standard reliability tests to ensure performance under stress. While specific test conditions are not listed in the excerpt, typical tests for such LEDs include: High Temperature Operating Life (HTOL), Temperature Humidity Bias (THB), Thermal Shock, and solderability tests. These validate the product's robustness for commercial applications.
7. Application Design Considerations
7.1 Driving the LED
Always drive LEDs with a constant current source, not a constant voltage. This ensures stable light output and protects the LED from thermal runaway. The driver should be sized for the forward voltage range (1.8-2.6V) and the desired operating current (e.g., 350mA). Pulse Width Modulation (PWM) dimming is preferred over analog current reduction for maintaining spectral characteristics.
7.2 Thermal Management Design
Thermal design is paramount. Use the thermal resistance (14°C/W) to calculate the temperature rise from the solder point to the junction: ΔT = RθJ-S * PD. The actual power dissipated as heat is PD ≈ VF * IF. Design the PCB with ample copper area connected to the thermal pad using multiple vias to spread heat into the board. For high-power arrays, consider metal-core PCBs (MCPCBs) or active cooling.
7.3 Optical Integration
The 30-degree viewing angle provides directivity. For broader coverage, secondary optics (reflectors or diffusers) may be required. When designing light fixtures, consider the specific photon flux density (PPFD) requirements of the target plants and the necessary hanging height to achieve uniform coverage.
8. Technical Comparison and Advantages
Compared to broader-spectrum white LEDs or fluorescent lamps for horticulture, this deep red LED offers distinct advantages:
- Spectral Efficiency: Emits almost all its energy in the photosynthetically active radiation (PAR) region that plants use most efficiently for photosynthesis, minimizing wasted energy in non-useful spectra.
- Phytochrome Control: The 660nm wavelength specifically converts phytochrome to its active form (PFR), allowing precise control over flowering and other photomorphogenic responses.
- Reduced Heat Load: While radiant efficiency is high, the narrow spectrum means less energy is converted to long-wave infrared (heat radiation) that could overheat plant leaves, compared to some broad-spectrum sources.
- Long Lifetime: Properly driven and cooled, AlGaInP LEDs typically offer lifetimes (L70/B50) exceeding 50,000 hours, significantly longer than HPS or fluorescent alternatives.
9. Frequently Asked Questions (FAQ)
9.1 Can I drive this LED at 500mA continuously?
While the absolute maximum rating is 500mA, the recommended operating condition is 350mA. Operating at 500mA will generate significantly more heat (higher junction temperature), which will reduce efficiency (luminous/radiant flux), accelerate wavelength shift, and shorten the operational lifetime. It is not recommended for continuous use without exceptional thermal management.
9.2 Why is the wavelength 660nm important for plants?
Chlorophyll absorption peaks in the red and blue regions. More importantly, plant photoreceptors called phytochromes are sensitive to red (660nm) and far-red (730nm) light. The ratio of these wavelengths triggers developmental processes like seed germination, stem elongation, and flowering. A 660nm source provides the key signal for promoting flowering and fruiting in many plants.
9.3 How do I interpret the Total Radiant Flux range (230-530mW)?
This reflects production binning. Higher-performing LEDs (higher radiant flux) are sorted into different bins, often corresponding to different product order codes. Designers should specify the required minimum flux for their application and select the appropriate bin. System design should be based on the minimum value to guarantee performance.
9.4 Is a heatsink necessary?
For a single LED at 350mA (dissipating roughly 0.7-1W), a well-designed PCB with sufficient copper may suffice if ambient temperatures are moderate. For arrays of LEDs or operation in high ambient temperatures, a dedicated heatsink attached to the PCB is almost always necessary to maintain a safe junction temperature.