LED Component Datasheet - Lifecycle Phase Revision 4 - Technical Documentation

1. Product Overview

This technical document provides comprehensive specifications and management information for a light-emitting diode (LED) component. The primary focus of this document is to establish and communicate the formal lifecycle status and revision history of the product's technical data. This ensures that engineers, designers, and procurement specialists are always referencing the correct and most up-to-date version of the component specifications, which is critical for maintaining consistency in design, manufacturing, and quality assurance processes. The document serves as the authoritative source for the component's defined parameters at a specific point in its development and release cycle.

The core advantage of this structured documentation lies in its role in supply chain and engineering change management. By clearly stating the lifecycle phase and revision number, it prevents the use of obsolete or incorrect data, thereby reducing the risk of design errors, component incompatibility, and production issues. It is targeted at the electronics manufacturing industry, particularly in applications requiring reliable and well-documented optoelectronic components, such as general lighting, automotive lighting, signage, and consumer electronics backlighting.

2. Lifecycle and Revision Management

The provided content exclusively details the administrative and control aspects of the component's datasheet.

2.1 Lifecycle Phase Definition

The document explicitly states the lifecycle phase as "Revision." This indicates that the component and its specifications are in a state of active management where updates, corrections, or improvements are being formally issued. A "Revision" phase is distinct from initial "Prototype" or final "Production" phases, signifying controlled evolution based on feedback, testing, or process refinement.

2.2 Revision Number

The revision number is specified as "4." This integer value is crucial for version control. It allows all stakeholders to identify the exact iteration of the document. Changes from Revision 3 to Revision 4 could encompass modifications to any technical parameter, packaging information, recommended application circuits, or test procedures. The absence of detailed change logs in the provided snippet highlights the importance of consulting the full document or associated engineering change notices (ECNs) for specifics.

2.3 Release and Validity Information

The document includes key metadata regarding its release and validity:

• Release Date: 2015-10-13 16:56:19.0. This timestamp provides an exact point of issuance for this revision.
• Expired Period: Forever. This denotes that this revision of the document does not have a pre-defined expiration date. It remains valid until superseded by a subsequent revision (e.g., Revision 5). The specification is considered stable for the duration of this revision's lifecycle.

3. Technical Parameters and Specifications

While the provided text snippet does not contain explicit technical parameters, a standard LED datasheet of this type would include the following sections. The values and curves mentioned below are illustrative examples based on common industry standards for a mid-power LED package.

3.1 Photometric and Color Characteristics

This section quantitatively defines the light output and color properties of the LED. Key parameters include:

• Luminous Flux: The total perceived power of light emitted, measured in lumens (lm). A typical value might be 20-30 lm at a standard test current (e.g., 65mA).
• Dominant Wavelength / Correlated Color Temperature (CCT): For colored LEDs (e.g., red, blue, green), the peak wavelength in nanometers (nm) is specified. For white LEDs, the CCT in Kelvin (K) is given (e.g., 3000K Warm White, 6500K Cool White).
• Color Rendering Index (CRI): For white LEDs, a Ra value indicating color accuracy, typically >80 for general lighting.
• Viewing Angle: The angular span where luminous intensity is at least half of the maximum, often 120 degrees.

3.2 Electrical Parameters

This section details the operating conditions and limits for the electrical drive of the LED.

• Forward Voltage (Vf): The voltage drop across the LED at a specified forward current. For a white LED, this typically ranges from 2.8V to 3.4V per diode. Series connections increase this value.
• Forward Current (If): The recommended continuous drive current, such as 65mA or 150mA. Absolute maximum ratings will also be listed to prevent damage.
• Reverse Voltage (Vr): The maximum allowable voltage in the reverse direction, usually around 5V, beyond which the LED junction may break down.

3.3 Thermal Characteristics

LED performance and lifespan are heavily dependent on junction temperature.

• Thermal Resistance (Rth j-s): The resistance to heat flow from the LED junction to the solder point or case, measured in °C/W. A lower value indicates better heat dissipation.
• Maximum Junction Temperature (Tj max): The highest allowable temperature at the semiconductor junction, often 125°C or 150°C.

4. Binning and Sorting System

Manufacturing variations necessitate sorting LEDs into performance bins to ensure consistency.

• Flux Binning: LEDs are grouped by luminous flux output (e.g., 20-22 lm, 22-24 lm, etc.).
• Color Binning: For white LEDs, bins are defined by CCT and Duv (distance from the black body locus) on the CIE chromaticity diagram to ensure color uniformity.
• Forward Voltage Binning: LEDs are sorted by their Vf at a test current to aid in circuit design for consistent brightness in parallel strings.

5. Performance Curve Analysis

Graphical data is essential for understanding device behavior under varying conditions.

• I-V (Current-Voltage) Curve: Shows the exponential relationship between forward current and voltage, crucial for driver design.
• Relative Flux vs. Forward Current: Demonstrates how light output increases with current, typically in a sub-linear fashion at higher currents due to heating.
• Relative Flux vs. Junction Temperature: Shows the decrease in light output as temperature rises, a key factor in thermal management design.
• Spectral Power Distribution (SPD): A graph plotting radiant power versus wavelength, defining the color characteristics.

6. Mechanical and Package Information

Precise physical specifications are required for PCB design and assembly.

• Package Dimensions: Detailed mechanical drawing with length, width, height, and tolerances (e.g., 2.8mm x 3.5mm x 1.2mm for a 2835 package).
• Pad Layout (Footprint): Recommended PCB land pattern design, including pad size, spacing, and solder mask openings.
• Polarity Identification: Clear marking of the anode and cathode, often via a notch, cut corner, or marking on the package.

7. Soldering and Assembly Guidelines

Proper handling ensures reliability.

• Reflow Soldering Profile: A time-temperature graph specifying preheat, soak, reflow peak temperature (typically 260°C max), and cooling rates compatible with the package.
• Handling Precautions: Protection from electrostatic discharge (ESD), avoidance of mechanical stress on the lens, and cleanliness requirements.
• Storage Conditions: Recommended temperature and humidity ranges for long-term storage (e.g., <40°C, <60% RH).

8. Packaging and Ordering Information

Information for logistics and procurement.

• Packaging Specification: Details on reel type (e.g., 12mm or 16mm), tape width, pocket dimensions, and quantity per reel (e.g., 2000 or 4000 pieces).
• Labeling: Explanation of information on the reel label, including part number, quantity, lot code, and date code.
• Part Numbering System: Decoding of the product model number, which typically includes codes for package type, color, flux bin, color bin, and voltage bin.

9. Application Notes and Design Considerations

Guidance for implementing the component effectively.

• Typical Application Circuits: Schematics for constant current driver circuits, either linear or switching regulator-based.
• Thermal Management: Critical design advice on PCB layout for heat sinking, using thermal vias, and connecting to metal cores or heatsinks to maintain low junction temperature.
• Optical Considerations: Notes on secondary optics (lenses, diffusers) and the impact of operating current on color shift and long-term lumen maintenance.

10. Technical Comparison and Differentiation

While not explicitly stated in the source, a component may offer advantages such as higher efficacy (lm/W), better color consistency across bins, lower thermal resistance for improved performance at high drive currents, or superior reliability metrics (longer L70/B50 life).

11. Frequently Asked Questions (FAQ)

Based on common technical queries:

• Q: Can I drive this LED with a constant voltage source? A: It is not recommended. LEDs are current-driven devices. A constant voltage source with a series resistor is inefficient and sensitive to Vf variations. A dedicated constant-current driver is essential for stable performance and longevity.
• Q: How do I interpret the "Forever" expired period? A: It means this specific revision of the datasheet has no set expiry and is valid indefinitely for referencing this product version. However, the component itself may become obsolete (EOL) in the future, which would be communicated separately.
• Q: Why is thermal management so critical? A: High junction temperature accelerates lumen depreciation (light output decrease over time) and can shift color. It is the primary factor limiting LED lifespan. Proper heatsinking is non-negotiable for reliable operation.

12. Practical Application Examples

Case Study 1: Linear LED Fixture. A designer uses this LED in a 4-foot tubular fixture. They connect 120 LEDs in a series-parallel configuration (e.g., 3 strings of 40 in series) powered by a constant-current driver. The design focuses on an aluminum PCB to dissipate heat, ensuring the junction temperature remains below 85°C to achieve the target 50,000-hour L90 lifespan.

Case Study 2: Backlight Unit (BLU). For an LCD TV, hundreds of these LEDs are mounted on a thin metal-core PCB. They are driven by a high-efficiency switching driver. The design challenge involves achieving uniform brightness and color across the entire panel, requiring careful selection of LEDs from tight flux and color bins and sophisticated optical films (diffusers, brightness enhancement films).

13. Operating Principle

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

14. Industry Trends

The LED industry continues to evolve towards higher efficacy (exceeding 200 lm/W in labs), improved color quality (higher CRI with R9 values), and greater reliability. Miniaturization of packages continues while maintaining or increasing light output. There is a strong trend towards intelligent, connected lighting using LEDs as a platform for sensors and communication (Li-Fi, Visible Light Communication). Furthermore, human-centric lighting, which tunes light spectrum and intensity to support circadian rhythms, is gaining traction, driving demand for LEDs with tunable CCT and spectral control.