LED Component Datasheet - Lifecycle Phase: Revision 1 - Release Date: 2014-12-16 - English Technical Document

1. Product Overview

This technical document pertains to a specific revision of an LED component. The primary information provided indicates the component is in the "Revision" phase of its lifecycle, with a revision number of 1. The release date for this revision is documented as December 16, 2014, at 12:06:03. The datasheet establishes that this revision has an "Expired Period" designated as "Forever," suggesting this version of the component data is intended to be the definitive and permanent reference for this particular revision cycle. The document serves as the official technical reference for engineers, procurement specialists, and quality assurance personnel involved in the design, sourcing, and manufacturing of products utilizing this component.

2. Technical Parameters and Specifications

While the provided excerpt focuses on administrative metadata, a complete datasheet for an LED component would typically include the following detailed technical parameters. These sections are critical for proper circuit design and thermal management.

2.1 Photometric and Color Characteristics

This section defines the light output and color properties of the LED. Key parameters include the dominant wavelength or correlated color temperature (CCT), which determines the color of the emitted light (e.g., cool white, warm white, or specific colors like red or blue). The luminous flux, measured in lumens (lm), indicates the total perceived power of light emitted. Other important metrics are the chromaticity coordinates (e.g., on the CIE 1931 diagram), which precisely define the color point, and the color rendering index (CRI), which measures the light source's ability to reveal the colors of objects faithfully compared to a natural light source. Viewing angle, specified in degrees, describes the angular distribution of the light intensity.

2.2 Electrical Parameters

Electrical specifications are fundamental for driving the LED correctly and ensuring longevity. The forward voltage (Vf) is the voltage drop across the LED when it is emitting light at a specified test current. It is crucial for designing the power supply and current-limiting circuitry. The forward current (If) is the recommended operating current, typically given as a nominal value and a maximum absolute rating. Exceeding the maximum current can cause permanent damage. Reverse voltage (Vr) specifies the maximum voltage the LED can withstand when biased in the non-conducting direction. Dynamic resistance may also be provided for more advanced modeling in pulsed or analog dimming applications.

2.3 Thermal Characteristics

LED performance and lifespan are heavily influenced by temperature. The junction temperature (Tj) is the temperature at the semiconductor chip itself, and it must be kept below a specified maximum rating, often 125°C or 150°C. The thermal resistance, from junction to ambient (RθJA) or junction to case (RθJC), quantifies how easily heat can flow away from the LED chip. A lower thermal resistance value indicates better heat dissipation. Proper heatsinking is essential to maintain a low junction temperature, which preserves luminous output, slows color shift, and dramatically extends operational life.

3. Binning and Classification System

Due to manufacturing variances, LEDs are sorted into performance bins. This system ensures consistency for the end-user.

3.1 Wavelength and Color Temperature Binning

LEDs are binned according to their dominant wavelength (for monochromatic LEDs) or correlated color temperature (for white LEDs). Bins are defined by small ranges on the chromaticity chart (e.g., MacAdam ellipses). Tighter binning results in more uniform color appearance across multiple LEDs in an assembly but may come at a higher cost.

3.2 Luminous Flux Binning

Luminous flux output is also binned. A typical binning scheme might categorize LEDs based on their minimum luminous flux at a standard test current. This allows designers to select components that meet specific brightness requirements for their application.

3.3 Forward Voltage Binning

Forward voltage is another parameter subject to binning. Grouping LEDs by similar Vf can simplify driver design, especially in series-connected strings, by ensuring more uniform current distribution and power dissipation.

4. Performance Curve Analysis

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

4.1 Current-Voltage (I-V) Characteristic Curve

The I-V curve shows the relationship between the forward voltage and the current through the LED. It is non-linear, exhibiting a turn-on voltage below which very little current flows. The curve's slope in the operating region relates to the dynamic resistance. This graph is essential for selecting appropriate driver topology (constant current vs. constant voltage).

4.2 Temperature Dependency Curves

These curves illustrate how key parameters change with junction temperature. Typically, they show the relative luminous flux decreasing as temperature increases. The forward voltage also decreases with rising temperature. Understanding these relationships is critical for designing systems that maintain consistent performance across their operating temperature range.

4.3 Spectral Power Distribution (SPD)

The SPD graph plots the radiant power emitted by the LED as a function of wavelength. For white LEDs, it shows the broad phosphor-converted spectrum superimposed on the blue pump LED's peak. This graph is used to calculate colorimetric data and assess color quality metrics like CRI and gamut area.

5. Mechanical and Package Information

Physical specifications ensure proper PCB layout and assembly.

5.1 Dimensional Outline Drawing

A detailed mechanical drawing provides all critical dimensions: length, width, height, lens shape, and lead spacing. It includes tolerances for each dimension. This drawing is used to create the PCB footprint and check for mechanical clearances in the final product.

5.2 Pad Layout and Solder Mask Design

The recommended PCB land pattern (footprint) is specified, including pad size, shape, and spacing. Guidelines for solder mask openings and solder paste stencil design (aperture size, thickness) are often provided to ensure reliable solder joint formation during reflow.

5.3 Polarity Identification

The method for identifying the anode and cathode is clearly indicated. This is typically done via a marking on the component body (such as a notch, dot, or cut corner), a longer lead, or a specific pad shape on the footprint (e.g., a square pad for the anode).

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. This includes key parameters: preheat ramp rate, soak temperature and time, peak temperature, time above liquidus (TAL), and cooling rate. The maximum allowable body temperature during soldering is specified to prevent damage to the LED package or internal die attach materials.

6.2 Handling and Storage Precautions

LEDs are sensitive to electrostatic discharge (ESD). Handling procedures should include the use of grounded workstations and wrist straps. Storage recommendations typically involve keeping components in their original moisture-barrier bags with desiccant, stored in a controlled environment (specific temperature and humidity range) to prevent moisture absorption, which can cause "popcorning" during reflow.

7. Packaging and Ordering Information

This section details how the components are supplied and how to specify them.

7.1 Packaging Specifications

The tape and reel specifications are provided, including reel diameter, tape width, pocket pitch, and component orientation. This information is necessary for automated pick-and-place machines. Quantities per reel are standard (e.g., 2000 or 4000 pieces).

7.2 Model Number Nomenclature

The part number coding system is explained. It typically includes codes for the package type, color/wavelength, luminous flux bin, forward voltage bin, and sometimes special features. Understanding this nomenclature is essential for accurately ordering the desired component variant.

8. Application Notes and Design Considerations

Practical advice for implementing the LED in a real-world design.

8.1 Typical Application Circuits

Schematics for basic drive circuits are shown. For low-power indicators, a simple series resistor with a voltage source is common. For higher-power or precision applications, constant current drivers (using linear regulators or switching converters) are recommended to ensure stable light output regardless of input voltage or temperature variations.

8.2 Thermal Management Design

Guidance is given on PCB layout for heat dissipation. This includes using thermal vias under the LED's thermal pad (if present), connecting to large copper planes, and potentially adding an external heatsink. Calculations for estimating junction temperature based on power dissipation and thermal resistance are often outlined.

9. Technical Comparison and Differentiation

While specific competitor names are omitted, the datasheet may highlight this component's key advantages. These could include higher luminous efficacy (lumens per watt), superior color consistency due to tight binning, a wider operating temperature range, enhanced reliability data (e.g., L70 lifetime ratings), or a more compact package size enabling higher-density designs. The "Forever" expired period for this revision suggests a commitment to long-term availability and design stability, which is a significant advantage for products with long lifecycles.

10. Frequently Asked Questions (FAQ)

Common technical queries based on the parameters are addressed.

• Q: What does "LifecyclePhase: Revision" mean?
  A: It indicates the component's technical data has been formally updated and released as a new, controlled revision. Revision 1 is the first such update.
• Q: How should I interpret "Expired Period: Forever"?
  A: It means this specific revision of the datasheet does not have a planned obsolescence date and is intended to remain the valid reference indefinitely for this product revision.
• Q: The release date is 2014. Is this product obsolete?
  A: Not necessarily. The release date indicates when this datasheet revision was published. The component itself may still be in production and widely used, especially in industrial and automotive applications where design cycles are long. The "Forever" expired period supports this.
• Q: How do I select the correct current-limiting resistor?
  A: Use the formula R = (Vsupply - Vf) / If, where Vf is the forward voltage from the datasheet (using the typical or maximum value depending on design margin) and If is the desired forward current. Ensure the resistor's power rating is sufficient: P = (If)^2 * R.

11. Practical Application Examples

Based on the technical parameters, here are hypothetical use cases.

Case 1: Backlighting for an Industrial Control Panel: An array of these LEDs could be used behind a diffuser to provide even, reliable illumination for buttons and displays. The long-term availability ("Forever" revision) is critical as these panels may be manufactured for decades. The designer would select a specific color temperature bin for consistency and use a constant-current driver array to ensure uniform brightness and compensate for any forward voltage variations.

Case 2: Status Indicator in a Network Router: A single LED, driven by a simple GPIO pin and series resistor, provides visual status feedback. The designer would ensure the forward current is set within the recommended range to achieve the desired brightness while maintaining long-term reliability. The component's ESD robustness and ability to withstand reflow soldering are key factors for this high-volume, automated assembly application.

12. Operational Principle

An LED is a semiconductor diode. When a forward voltage is applied, electrons from the n-type semiconductor and holes from the p-type semiconductor are injected into the active region. When an electron recombines with a hole, energy is released in the form of a photon (light). The wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor materials used in the active region. White LEDs are typically created by using a blue LED chip coated with a phosphor material. The phosphor absorbs a portion of the blue light and re-emits it as a broader spectrum of longer wavelengths (yellow, red), mixing with the remaining blue light to produce white.

13. Technology Trends

The LED industry continues to evolve. General trends include ongoing improvements in luminous efficacy, pushing past 200 lumens per watt for some high-performance white LEDs. There is a strong focus on improving color quality, with high-CRI (90+) and full-spectrum LEDs becoming more common for applications where accurate color rendition is critical. Miniaturization continues, enabling ever-smaller pixel pitches in direct-view displays. In terms of intelligence and control, integration of drivers and control circuitry directly into LED packages ("smart LEDs") is a growing trend, simplifying system design. Furthermore, there is increased emphasis on sustainability, with longer lifetime ratings reducing waste and more efficient manufacturing processes.