LED Component Specification - Lifecycle Revision 2 - Forever Expiry - English Technical Document

1. Product Overview

This technical document provides comprehensive specifications for a light-emitting diode (LED) component. The primary focus of this document is to detail the product's lifecycle management, revision control, and long-term availability status. The component is designed for general illumination and indicator applications, offering reliable performance and stable characteristics over its operational lifetime. The core advantage of this product lies in its documented "Forever" expiry period, indicating indefinite availability or support for this specific revision, which is a critical factor for long-term product designs and supply chain planning in industries such as consumer electronics, automotive lighting, and industrial controls. The target market includes manufacturers of lighting fixtures, electronic assemblies, and any application requiring consistent, long-term sourcing of optoelectronic components.

2. In-Depth Technical Parameter Interpretation

While the provided PDF excerpt focuses on administrative data, a complete LED datasheet would typically include detailed technical parameters. The following sections outline the standard parameters that are critical for design engineers, based on industry-standard LED specifications.

2.1 Photometric and Color Characteristics

Photometric characteristics define the light output and quality. Key parameters include luminous flux (measured in lumens, lm), which indicates the total perceived power of light emitted. The correlated color temperature (CCT), measured in Kelvin (K), defines whether the light appears warm (e.g., 2700K-3000K), neutral (e.g., 4000K-4500K), or cool (e.g., 5000K-6500K). Color Rendering Index (CRI) is a measure of a light source's ability to reveal the colors of various objects faithfully in comparison to a natural light source, with a higher Ra value (typically >80 for general lighting) being desirable. Dominant wavelength or peak wavelength specifies the perceived color of the emitted light (e.g., 450nm for blue, 525nm for green, 630nm for red). For white LEDs, the chromaticity coordinates (x, y) on the CIE 1931 color space diagram are provided to ensure color consistency.

2.2 Electrical Parameters

Electrical parameters are fundamental for circuit design. The forward voltage (Vf) is the voltage drop across the LED when it is emitting light at a specified forward current (If). This parameter has a typical value and a range (e.g., 3.0V to 3.4V at 20mA). The forward current (If) is the recommended operating current, and exceeding the absolute maximum rating can drastically reduce lifespan or cause immediate failure. Reverse voltage (Vr) is the maximum voltage the LED can withstand when connected in reverse bias without damage. Power dissipation is calculated as Vf * If and must be managed thermally.

2.3 Thermal Characteristics

LED performance and longevity are heavily dependent on junction temperature (Tj). The thermal resistance from junction to ambient (RθJA) or junction to solder point (RθJS) indicates how easily heat can escape from the semiconductor junction. A lower thermal resistance is better. The maximum allowable junction temperature (Tj max) is the highest temperature the LED chip can sustain without permanent degradation. Proper heat sinking is required to keep Tj within safe limits, as elevated temperatures lead to lumen depreciation, color shift, and reduced operational life.

3. Binning System Explanation

LED manufacturing yields variations. Binning is the process of sorting LEDs into groups (bins) based on key parameters to ensure consistency within a production lot.

3.1 Wavelength/Color Temperature Binning

LEDs are binned according to their chromaticity coordinates on the CIE diagram. For white LEDs, this often corresponds to MacAdam ellipses (e.g., 2-step, 3-step, 5-step), where a smaller step number indicates tighter color consistency. For monochromatic LEDs, bins are defined by dominant wavelength ranges (e.g., 620-625nm, 626-630nm).

3.2 Luminous Flux Binning

LEDs are sorted by their light output at a standard test current. Bins are labeled with codes (e.g., L1, L2, M1, M2) representing minimum and maximum flux values. This allows designers to select the appropriate brightness grade for their application.

3.3 Forward Voltage Binning

To simplify driver design and ensure uniform brightness in arrays, LEDs are also binned by forward voltage (Vf). Common bins group Vf within a specific range (e.g., 2.8V-3.0V, 3.0V-3.2V). Using LEDs from the same Vf bin helps prevent current hogging in parallel configurations.

4. Performance Curve Analysis

Graphical data provides deeper insight into LED behavior under varying conditions.

4.1 Current-Voltage (I-V) Characteristic Curve

This curve plots the relationship between forward current (If) and forward voltage (Vf). It is non-linear, exhibiting a knee voltage below which very little current flows. The curve's slope in the operating region helps determine dynamic resistance. This graph is essential for designing constant current drivers.

4.2 Temperature Dependency Characteristics

Several graphs illustrate temperature effects. Luminous flux vs. junction temperature typically shows output decreasing as temperature increases. Forward voltage vs. junction temperature usually shows a negative coefficient (Vf decreases as Tj increases). Understanding these relationships is crucial for thermal management and optical design.

4.3 Spectral Power Distribution (SPD)

The SPD graph shows the relative intensity of light emitted at each wavelength. For white LEDs (typically phosphor-converted), it shows a blue peak from the chip and a broader yellow/red peak from the phosphor. This graph is used to calculate CCT, CRI, and other color metrics.

5. Mechanical and Package Information

Physical dimensions and construction details ensure proper PCB layout and assembly.

5.1 Outline Dimension Drawing

A detailed mechanical drawing provides all critical dimensions: package length, width, height, lens shape, and any tolerances. Common surface-mount device (SMD) packages include 2835, 3535, 5050, etc., where the numbers often refer to length and width in tenths of a millimeter (e.g., 2.8mm x 3.5mm).

5.2 Pad Layout and Solder Land Pattern

The recommended PCB footprint (land pattern) is provided, including pad size, shape, spacing, and any thermal pad recommendations. A proper land pattern ensures good solder joint reliability and effective heat transfer to the PCB.

5.3 Polarity Identification

The method for identifying the anode (+) and cathode (-) terminals is specified. This is typically a marking on the package (e.g., a green dot, a notch, a cut corner, or a "T" mark) or a difference in lead length or pad size.

6. Soldering and Assembly Guidelines

Proper handling ensures component integrity and long-term reliability.

6.1 Reflow Soldering Profile

A detailed temperature vs. time profile is provided, specifying preheat, soak, reflow, and cooling stages. Key parameters include peak temperature (typically 260°C maximum for Pb-free solder), time above liquidus (TAL), and ramp rates. Adherence to this profile prevents thermal shock and damage.

6.2 Precautions and Handling Notes

Guidelines include: avoiding mechanical stress on the lens, using ESD precautions as LEDs are static-sensitive devices, cleaning recommendations (avoiding certain solvents that may damage the lens or encapsulant), and not touching the optical surface with bare hands.

6.3 Storage Conditions

Recommended storage conditions to prevent moisture absorption (which can cause "popcorning" during reflow) and material degradation. This often includes storing in a dry environment (<40°C and <60% relative humidity) in moisture barrier bags with desiccant.

7. Packaging and Ordering Information

Information for procurement and logistics.

7.1 Packaging Specifications

Describes the packaging format, such as tape and reel (standard sizes: 7", 13", 15" reels), antistatic properties, quantity per reel (e.g., 2000 pcs/reel), and reel dimensions.

7.2 Labeling and Marking

Explains the markings on the component itself (often a 2- or 3-character code indicating binning information) and the labels on the packaging (including part number, lot code, date code, quantity, and bin codes).

7.3 Part Numbering System

Decodes the part number structure. A typical part number includes codes for package type, color, flux bin, color temperature bin, voltage bin, and sometimes special features. Understanding this allows precise ordering of the required specification.

8. Application Recommendations

Guidance for implementing the component effectively.

8.1 Typical Application Circuits

Schematics for basic drive circuits, such as using a series resistor with a constant voltage source or employing a dedicated constant-current LED driver IC. Considerations for series/parallel connections are discussed.

8.2 Design Considerations

Key points include: thermal management via PCB copper area or external heatsinks, optical design for desired beam pattern, dimming method compatibility (PWM vs. analog), and protection against electrical transients (ESD, surge).

9. Technical Comparison and Differentiation

While specific competitor names are omitted, this section objectively highlights the potential advantages of this component's design based on its specified parameters. This could include higher efficacy (lumens per watt), better color consistency (tighter binning), lower thermal resistance, superior reliability data (L70/B50 lifetime), or a unique feature like the "Forever" lifecycle status mentioned in the PDF, which assures long-term design stability.

10. Frequently Asked Questions (FAQs)

Answers to common technical queries based on the datasheet parameters.

• Q: What does "Lifecycle Phase: Revision 2" mean?
  A: It indicates this is the second major revision of the product's documentation and/or specifications. Changes from Revision 1 would be documented in a revision history section.
• Q: What is implied by "Expired Period: Forever"?
  A: This suggests the component, in this specific revision, is not planned for obsolescence and will remain available for purchase indefinitely, or its specification is frozen and valid permanently for reference.
• Q: How do I select the correct bin for my application?
  A: Choose based on your priority: for color-critical applications (e.g., retail lighting), prioritize tight CCT/CRI bins. For cost-sensitive applications with less strict color needs, a broader bin may be acceptable. For uniform brightness in arrays, use the same flux bin.
• Q: Can I drive the LED above its rated current for more brightness?
  A: No. Exceeding the absolute maximum forward current rating will significantly increase junction temperature, leading to rapid lumen depreciation, color shift, and catastrophic failure. Always operate within specified limits.
• Q: How important is the thermal pad on the PCB?
  A> Crucial. The thermal pad is the primary path for heat dissipation. A properly designed pad with adequate vias connecting to internal ground planes is essential for maintaining low junction temperature and achieving rated lifetime and performance.

11. Practical Application Case Studies

Example 1: Linear LED Fixture. A designer uses this LED in a 4-foot tubular fixture. By selecting LEDs from a single, tight CCT bin (3-step MacAdam), they ensure consistent white light along the entire length. The high-efficacy bins allow them to meet energy code requirements. The "Forever" lifecycle assures the fixture manufacturer of a stable bill of materials for years of production.

Example 2: Automotive Interior Lighting. The LED is used for map lights and door puddle lights. The robust specification for operating temperature range and high reliability data makes it suitable for the harsh automotive environment. The consistent Vf binning simplifies the design of the driver circuit for multiple LEDs in parallel.

12. Operating Principle Introduction

An LED is a semiconductor p-n junction diode. When a forward voltage is applied, electrons from the n-type region and holes from the p-type region are injected into the junction region. When these charge carriers recombine, energy is released in the form of photons (light). The wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor material used (e.g., InGaN for blue/green, AlInGaP for red/amber). White LEDs are typically created by coating a blue LED chip with a yellow phosphor; some of the blue light is converted to yellow, and the mixture of blue and yellow light is perceived as white.

13. Technology Development Trends

The LED industry continues to evolve with several clear trends. Efficacy (lumens per watt) is steadily increasing, reducing energy consumption for the same light output. Color quality is improving, with high-CRI (Ra>90, R9>50) LEDs becoming more common and affordable. Miniaturization continues, enabling higher pixel density in direct-view displays. There is a strong focus on reliability and lifetime prediction under various stress conditions. Furthermore, smart and connected lighting, integrating sensors and communication protocols directly with LED modules, is a growing application area. The trend towards human-centric lighting, which considers the non-visual effects of light on circadian rhythms, is also driving spectral tuning capabilities in LED products.