LED Component Datasheet - Revision 4 - Lifecycle Information - English Technical Document

1. Product Overview

This technical document provides comprehensive specifications and application guidelines for a specific LED (Light Emitting Diode) component. The primary focus of the provided content is the formal declaration of the document's lifecycle status, which is identified as "Revision 4". This indicates the fourth official iteration of this datasheet, incorporating updates, corrections, or enhancements over previous versions. The document is designated with an "Expired Period" of "Forever," signifying its intended validity and relevance for an indefinite duration, barring any future superseding revisions. The official release timestamp for this revision is recorded as October 16, 2015, at 11:07:50. This information is crucial for engineers, procurement specialists, and quality assurance personnel to ensure they are referencing the correct and most current version of the component's specifications for design, sourcing, and manufacturing processes.

2. In-Depth Technical Parameter Analysis

While the core excerpt emphasizes lifecycle data, a complete LED datasheet typically contains several critical technical parameter sections essential for proper integration into an electronic design. These parameters must be carefully considered to ensure optimal performance, reliability, and longevity of the final product.

2.1 Photometric and Color Characteristics

The photometric properties define the light output of the LED. Key parameters include the dominant wavelength or correlated color temperature (CCT), which determines the perceived color of the light (e.g., cool white, warm white, red, blue, green). Luminous flux, measured in lumens (lm), quantifies the total amount of visible light emitted. Other important metrics are luminous intensity (candelas), which describes the light output in a specific direction, and the color rendering index (CRI), which indicates how accurately the light source reveals the true colors of objects compared to a natural light source. The viewing angle specifies the angular range over which the luminous intensity is at least half of its maximum value, defining the beam spread.

2.2 Electrical Parameters

Electrical specifications are fundamental for circuit design. The forward voltage (Vf) is the voltage drop across the LED when it is operating at its specified current. It is a critical parameter for determining the necessary drive voltage and for thermal management calculations, as power dissipation is the product of forward voltage and current. The forward current (If) is the recommended operating current for achieving the specified photometric output. Absolute maximum ratings, such as the maximum reverse voltage and peak forward current, define the operational limits that must not be exceeded to prevent permanent damage. The dynamic resistance of the LED can also be important for certain driver topologies.

2.3 Thermal Characteristics

LED performance and lifespan are highly dependent on operating temperature. The junction temperature (Tj) is the temperature at the semiconductor chip itself. Key thermal parameters include the thermal resistance from the junction to the solder point or ambient (Rth j-s or Rth j-a), which indicates how effectively heat is conducted away from the chip. The maximum allowable junction temperature (Tj max) must not be exceeded. Proper heat sinking and PCB design are essential to maintain Tj within safe limits, as elevated temperatures lead to reduced light output (lumen depreciation), color shift, and accelerated failure.

3. Binning System Explanation

Due to inherent variations in semiconductor manufacturing, LEDs are sorted into performance bins. A binning system ensures consistency for the end user.

3.1 Wavelength/Color Temperature Binning

LEDs are binned according to their dominant wavelength (for monochromatic LEDs) or correlated color temperature (for white LEDs). This ensures that all LEDs used in a single product or batch fall within a narrow, predefined color range, preventing visible color differences between individual LEDs.

3.2 Luminous Flux Binning

LEDs are also sorted based on their measured light output at a standard test current. Flux bins group LEDs with similar luminous flux values, allowing designers to select components that meet specific brightness requirements and ensure uniformity in the final application.

3.3 Forward Voltage Binning

Forward voltage is another parameter subject to binning. Grouping LEDs by Vf helps in designing more efficient driver circuits, especially when multiple LEDs are connected in series, as it minimizes current imbalances and power losses.

4. Performance Curve Analysis

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

4.1 Current-Voltage (I-V) Characteristic Curve

The I-V curve illustrates the relationship between the forward current through the LED and the voltage across it. It is non-linear, showing a threshold voltage below which very little current flows. This curve is essential for selecting appropriate current-limiting circuitry, such as resistors or constant-current drivers.

4.2 Temperature Dependency

Graphs showing luminous flux versus junction temperature and forward voltage versus junction temperature are critical. Typically, luminous output decreases as temperature increases. Forward voltage also decreases with rising temperature, which can affect the performance of simple resistive drive circuits.

4.3 Spectral Power Distribution

For white LEDs, the SPD graph shows the relative intensity of light emitted at each wavelength across the visible spectrum. It reveals the peaks of the blue pump LED and the broader phosphor emission, providing information about color quality and potential applications.

5. Mechanical and Package Information

Physical dimensions and construction details are necessary for PCB layout and assembly.

5.1 Outline Dimension Drawing

A detailed mechanical drawing specifies the package's exact length, width, height, and any critical tolerances. This includes the lens shape and size.

5.2 Pad Layout and Footprint Design

The recommended PCB land pattern (footprint) is provided, including pad dimensions, spacing, and shape. Adhering to this design ensures proper solder joint formation and mechanical stability.

5.3 Polarity Identification

The method for identifying the anode and cathode is clearly indicated, typically through a marking on the package (such as a notch, dot, or cut corner) or via asymmetric lead lengths. Correct polarity is essential for device operation.

6. Soldering and Assembly Guidelines

Proper handling and assembly are vital for reliability.

6.1 Reflow Soldering Profile

A recommended reflow temperature profile is provided, including preheat, soak, reflow peak temperature, and cooling rates. The maximum allowable body temperature during soldering is specified to prevent damage to the plastic package and internal wire bonds.

6.2 Handling and Storage Precautions

Guidelines cover protection from electrostatic discharge (ESD), which can damage the semiconductor junction. Recommendations for storage conditions (temperature and humidity) to prevent moisture absorption are also included, often referencing MSL (Moisture Sensitivity Level) ratings.

7. Packaging and Ordering Information

This section details how the components are supplied.

7.1 Packaging Specifications

Information includes the reel type (e.g., tape width, pocket size), number of components per reel, and reel dimensions. For other formats, details on trays or tubes are provided.

7.2 Labeling and Part Numbering

The labeling on the reel or package is explained. The part number structure is decoded, showing how to identify the specific bin codes for flux, color, and voltage within the full ordering code.

8. Application Recommendations

Guidance on how to best utilize the component.

8.1 Typical Application Circuits

Schematics for basic drive circuits are often shown, such as using a series resistor with a constant voltage source or employing a dedicated constant-current LED driver IC for better efficiency and control.

8.2 Design Considerations

Key design advice includes ensuring adequate heat sinking on the PCB (using thermal vias, copper pours), calculating the correct current-limiting resistor, considering the effects of dimming (PWM vs. analog), and ensuring optical design (lenses, diffusers) is compatible with the LED's viewing angle and intensity profile.

9. Technical Comparison and Differentiation

While specific competitor names are omitted, the datasheet may highlight this component's advantages. These could include higher luminous efficacy (more lumens per watt), better color consistency (tighter binning), superior reliability data (longer L70/B50 lifetime), a more compact package size enabling higher density designs, or a wider operating temperature range suitable for harsh environments.

10. Frequently Asked Questions (FAQ)

Answers to common technical queries based on the parameters.

Q: What happens if I operate the LED above the maximum forward current?
A: Exceeding If(max) will cause excessive junction temperature, leading to rapid lumen depreciation, permanent color shift, and ultimately catastrophic failure. Always design with a safety margin.

Q: How do I select the right current-limiting resistor?
A: Use Ohm's Law: R = (Vsupply - Vf_total) / If. Where Vf_total is the sum of forward voltages for LEDs in series. Ensure the resistor's power rating is sufficient: P = (If)^2 * R.

Q: Why is thermal management so important for LEDs?
A: Unlike incandescent bulbs, LEDs are sensitive to heat. High Tj directly reduces light output and lifespan. Effective heat sinking maintains performance and ensures the product meets its rated lifetime.

11. Practical Application Case Studies

Case Study 1: Architectural Linear Lighting
In a continuous LED strip for cove lighting, consistent color temperature (tight CCT binning) is paramount to avoid visible variations along the run. High CRI bins would be selected for retail applications to ensure merchandise appears true to color. The design must manage heat along the entire length of the flexible PCB.

Case Study 2: Automotive Interior Lighting
For dashboard backlighting, LEDs must operate reliably across a wide temperature range (-40°C to +85°C ambient). Stable forward voltage characteristics are important for dimming circuits. The package must also withstand automotive-grade reliability tests for vibration and humidity.

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 recombine with holes from the p-type region within the active layer. This recombination releases energy in the form of photons (light), a process called electroluminescence. The specific 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; the mixture of blue and yellow light produces white light.

13. Technology Trends and Developments

The LED industry continues to evolve driven by demands for higher efficiency, better quality, and lower cost. Key trends include the ongoing improvement of luminous efficacy, pushing beyond 200 lumens per watt for commercial white LEDs. There is a strong focus on enhancing color quality, with high-CRI and full-spectrum LEDs becoming more common for applications where color fidelity is critical. Miniaturization persists, enabling ever-smaller pixel pitches in direct-view displays. Furthermore, the integration of smart features, such as built-in drivers and color-tuning capabilities within the package, is simplifying system design for connected lighting applications. Research into novel materials, like perovskites for next-generation color conversion, points to future performance leaps.