LED Component Datasheet - Revision 3 - Lifecycle Phase - Forever Release - English Technical Document

1. Product Overview

This technical datasheet provides comprehensive specifications for a light-emitting diode (LED) component. The document is currently in its third revision, indicating a mature and stable product design with finalized parameters. The lifecycle phase is designated as "Revision," and the product has a release date of December 5, 2014. The expiration period is marked as "Forever," signifying that this version of the datasheet remains valid indefinitely for reference and design purposes, though users are always advised to check for the latest available documentation for new designs.

The core advantage of this component lies in its well-defined and stable technical characteristics, having undergone multiple revisions to optimize performance and reliability. It is suitable for a wide range of general lighting, indicator, and backlighting applications where consistent performance is required.

2. In-Depth Technical Parameter Analysis

While the provided PDF excerpt focuses on document metadata, a typical LED datasheet of this nature would contain detailed technical parameters. The following sections outline the expected and critical parameters that define the component's performance.

2.1 Photometric and Color Characteristics

The photometric properties are fundamental for lighting design. Key parameters include:

• Luminous Flux: The total visible light emitted by the LED, measured in lumens (lm). This value is typically specified at a standard test current (e.g., 20mA, 65mA, 150mA) and junction temperature (e.g., 25°C).
• Dominant Wavelength / Correlated Color Temperature (CCT): For colored LEDs, the dominant wavelength (in nanometers) defines the perceived color (e.g., 630nm for red, 525nm for green, 470nm for blue). For white LEDs, the CCT (in Kelvin, K) indicates whether the light is warm white (e.g., 2700K-3500K), neutral white (e.g., 4000K-5000K), or cool white (e.g., 5700K-6500K).
• Color Rendering Index (CRI): For white LEDs, CRI (Ra) measures the ability to reveal the colors of objects faithfully compared to an ideal light source. A higher CRI (closer to 100) is desirable for applications requiring accurate color perception.
• Viewing Angle: The angle at which the luminous intensity is half of the maximum intensity (typically denoted as 2θ½). Common viewing angles are 120°, 140°, or specific narrow beams.

2.2 Electrical Parameters

Electrical specifications are crucial for circuit design and driver selection.

• Forward Voltage (V_F): The voltage drop across the LED when operating at a specified forward current. This is a critical parameter for power supply design and thermal management. V_F typically has a range (e.g., 2.8V to 3.4V at 20mA) and is temperature-dependent.
• Forward Current (I_F): The recommended continuous operating current. Exceeding the maximum rated forward current can drastically reduce lifespan or cause immediate failure.
• Reverse Voltage (V_R): The maximum voltage that can be applied in the reverse direction without damaging the LED. LEDs have very low reverse voltage ratings (typically 5V).
• Power Dissipation: The electrical power converted into heat (V_F * I_F), which must be managed through proper heatsinking.

2.3 Thermal Characteristics

LED performance and longevity are highly sensitive to temperature.

• Junction Temperature (T_j): The temperature at the semiconductor chip's p-n junction. The maximum allowable T_j (e.g., 125°C) is a key reliability limit.
• Thermal Resistance (R_θJA or R_θJC): The resistance to heat flow from the junction to the ambient (JA) or case (JC). Lower thermal resistance values indicate better heat dissipation capability, which is essential for maintaining performance and lifespan.
• Temperature Derating Curves: Graphs showing how maximum forward current must be reduced as ambient or case temperature increases to keep the junction temperature within safe limits.

3. Binning System Explanation

Due to manufacturing variations, LEDs are sorted into performance bins. This system ensures designers receive components within specified tolerances.

• Wavelength / CCT Binning: LEDs are grouped into tight wavelength or CCT ranges (e.g., 3-step, 5-step MacAdam ellipses for white LEDs) to ensure color consistency within a batch.
• Luminous Flux Binning: LEDs are sorted based on their measured light output at a standard test condition, allowing selection of components for specific brightness requirements.
• Forward Voltage Binning: Sorting by V_F range helps in designing efficient driver circuits and managing power distribution in arrays.

4. Performance Curve Analysis

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

• I-V (Current-Voltage) Characteristic Curve: Shows the relationship between forward current and forward voltage. It is non-linear, and the operating point is set by the driver circuit.
• Relative Luminous Flux vs. Forward Current: Demonstrates how light output increases with current, typically in a sub-linear manner at higher currents due to efficiency droop and heating.
• Relative Luminous Flux vs. Junction Temperature: Shows the decrease in light output as junction temperature rises. This thermal quenching effect is a critical design consideration.
• Spectral Power Distribution (SPD): A graph plotting the intensity of light emitted at each wavelength. For white LEDs, this shows the blue pump peak and the broader phosphor-converted spectrum.

5. Mechanical and Packaging Information

Physical dimensions and assembly details are essential for PCB layout and mechanical integration.

• 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 (pad size, shape, and spacing) to ensure reliable soldering and thermal connection.
• Polarity Identification: Clear marking (e.g., a notch, cut corner, or cathode mark) to indicate the anode and cathode terminals for correct electrical connection.
• Lens and Package Material: Description of the encapsulant (e.g., silicone, epoxy) and lens shape (dome, flat) which affect the light distribution.

6. Soldering and Assembly Guidelines

Proper handling and assembly are critical for reliability.

• Reflow Soldering Profile: Recommended time-temperature profile for lead-free (e.g., SnAgCu) or tin-lead soldering, including preheat, soak, reflow peak temperature (typically not exceeding 260°C), and cooling rates.
• Hand Soldering Instructions: If applicable, guidelines for temperature and duration for manual soldering.
• ESD (Electrostatic Discharge) Sensitivity: Most LEDs are sensitive to ESD and require handling in an ESD-protected area using appropriate grounding.
• Storage Conditions: Recommended temperature and humidity ranges for long-term storage (e.g., <40°C, <60% RH) to prevent moisture absorption and degradation.

7. Packaging and Ordering Information

Information related to logistics and procurement.

• Reel/Tape Specifications: Details of the carrier tape width, pocket dimensions, reel diameter, and quantity per reel (e.g., 4000 pieces per 13-inch reel).
• Model Numbering Rule: Explanation of how the part number encodes key attributes like color, flux bin, voltage bin, CCT, and package type.
• Labeling and Traceability: Description of information printed on the reel label, including part number, lot code, quantity, and date code.

8. Application Recommendations

Guidance for implementing the component effectively.

• Typical Application Circuits: Schematic examples showing the LED driven by a constant current source or with a simple current-limiting resistor.
• Thermal Management Design: Critical advice on PCB layout for heat dissipation, such as using thermal vias, adequate copper area, and possibly a metal-core PCB (MCPCB) for high-power applications.
• Optical Design Considerations: Notes on secondary optics (lenses, reflectors) and the impact of the LED's viewing angle on the final light distribution.
• Reliability and Lifespan: Discussion of factors affecting LED lifespan (L70, L50), primarily driven by operating current and junction temperature. Derating guidelines to achieve target lifetimes.

9. Technical Comparison and Differentiation

While specific competitor names are omitted, the datasheet implies a product refined through three revisions. Potential differentiation points based on common industry benchmarks include:

• High Luminous Efficacy: Potentially offering more lumens per watt compared to earlier generations or standard products, leading to higher energy efficiency.
• Superior Color Consistency: Tight binning tolerances for wavelength and CCT, reducing color shift in multi-LED assemblies.
• Robust Thermal Performance: Low thermal resistance package design enabling higher drive currents or better longevity in compact spaces.
• High Reliability and Lifetime: Proven performance from a mature revision, with data supporting long-term lumen maintenance under specified conditions.

10. Frequently Asked Questions (FAQs)

Answers to common design questions based on technical parameters.

• Q: Can I drive this LED with a voltage source? A: No. LEDs are current-driven devices. A constant current driver or a voltage source with a series current-limiting resistor is mandatory to prevent thermal runaway and destruction.
• Q: Why does the light output of my LED array vary between units? A: This is likely due to not accounting for forward voltage (V_F) binning. When connecting LEDs in parallel without individual current control, differences in V_F cause uneven current distribution. A series connection or individual drivers per LED is recommended.
• Q: The LED dims over time. Is this normal? A: Yes, all LEDs experience lumen depreciation. The rate is primarily determined by the operating junction temperature. Operating at or below the recommended current and with effective thermal management will maximize lifespan (e.g., L70 - time to 70% of initial lumens).
• Q: What is the impact of PWM dimming on LED life? A: Properly implemented PWM (Pulse Width Modulation) dimming at a sufficiently high frequency (>100Hz) does not negatively affect LED life, as it switches the LED between fully on and off states without altering the current amplitude.

11. Practical Design and Usage Cases

Illustrative examples of how the component's parameters translate into real-world designs.

• Case 1: Linear LED Module for Architectural Cove Lighting: A design using 50 LEDs in series, driven by a single constant current driver. The total forward voltage is calculated by summing the typical V_F of each LED. Thermal management is achieved by mounting the LEDs on an aluminum PCB strip, with calculations performed to ensure the junction temperature remains below 85°C for a target L90 lifetime of 50,000 hours.
• Case 2: Backlight Unit for an Industrial Display: An array of 100 LEDs arranged in a 10x10 matrix on a standard FR4 PCB. To ensure uniform brightness, LEDs from a single luminous flux bin are used. A diffuser layer is placed over the array to homogenize the light. The design uses parallel strings of series-connected LEDs with balancing resistors to manage V_F variations.

12. Operating Principle Introduction

An LED is a semiconductor diode. When a forward voltage is applied, electrons from the n-type material recombine with holes from the p-type material at the junction, releasing energy 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 phosphor material that converts some of the blue light into longer wavelengths (yellow, red), resulting in white light.

13. Technology Trends and Developments

The LED industry continues to evolve. While this datasheet represents a stable product, broader trends include:

• Increased Efficacy: Ongoing research aims to produce more lumens per watt, reducing energy consumption for the same light output.
• Improved Color Quality: Development of phosphors and multi-chip solutions to achieve higher CRI values and more saturated colors for specialized applications.
• Miniaturization and Integration: Trends towards smaller package sizes (e.g., micro-LEDs) and integrated modules combining LEDs, drivers, and control circuitry (e.g., COB - Chip-on-Board).
• Smart and Connected Lighting: Integration of sensors, communication protocols (Zigbee, Bluetooth, DALI), and IoT capabilities into lighting systems, though this is typically at the system level rather than the component level described in this datasheet.