LED Component Technical Datasheet - Dimensions 2.8x3.5x1.2mm - Voltage 3.2V - Power 0.2W - White Color - English Technical Documentation

1. Product Overview

This document provides the complete technical specifications and application guidelines for a high-performance surface-mount LED (Light Emitting Diode) component. The component is designed for general-purpose illumination and indicator applications across various electronic devices and systems. Its primary function is to convert electrical energy into visible light with high efficiency and reliability.

The core advantages of this LED include its compact form factor, which allows for high-density PCB (Printed Circuit Board) layouts, excellent luminous efficacy for energy savings, and robust construction suitable for automated assembly processes. The target market encompasses consumer electronics, automotive interior lighting, industrial control panels, and smart home devices where reliable, long-lasting, and efficient light sources are required.

The lifecycle phase indicated in the provided content is "Revision 2," signifying this is the second official revision of the product's technical documentation. The release date is documented as December 5, 2014. The "Expired Period" is noted as "Forever," which typically indicates that this revision of the document does not have a planned obsolescence date and remains valid until superseded by a newer revision. This is common for foundational component datasheets.

2. In-Depth Technical Parameter Analysis

A detailed, objective interpretation of the key technical parameters is essential for proper design integration. While specific numerical values from the original PDF are limited, the following sections outline the critical parameter categories and their significance.

2.1 Photometric and Color Characteristics

The photometric properties define the light output and quality. Key parameters include:

• Luminous Flux: Measured in lumens (lm), this indicates the total perceived power of light emitted. The component likely features a standard or high-brightness binning to ensure consistent light output across production batches.
• Dominant Wavelength / Correlated Color Temperature (CCT): For colored LEDs, the dominant wavelength (in nanometers) specifies the color. For white LEDs, the CCT (in Kelvin, e.g., 3000K, 4000K, 6500K) defines whether the light appears warm, neutral, or cool white. The document would specify the standard offering and available bins.
• Color Rendering Index (CRI): For white LEDs, CRI (Ra) indicates how accurately the light source reveals the true colors of objects compared to a natural reference. A higher CRI (closer to 100) is preferable for applications requiring accurate color perception.

2.2 Electrical Parameters

Electrical parameters are crucial for circuit design and power supply selection.

• Forward Voltage (Vf): The voltage drop across the LED when operating at its specified current. This value, typically around 3.2V for common white LEDs, varies slightly with current and temperature. The datasheet provides a typical value and a maximum limit.
• Forward Current (If): The recommended continuous operating current, often 20mA, 60mA, or 150mA depending on the power rating. Exceeding the absolute maximum rating can cause permanent damage.
• Reverse Voltage (Vr): The maximum voltage the LED can withstand in the reverse-biased direction without breakdown, usually around 5V. Protection is often needed in AC or multiplexed circuits.
• Power Dissipation: Calculated as Vf * If, this determines the thermal load. The example title suggests a 0.2W power rating.

2.3 Thermal Characteristics

LED performance and lifespan are heavily influenced by temperature.

• Junction Temperature (Tj): The temperature at the semiconductor chip itself. The absolute maximum Tj (e.g., 125°C) must not be exceeded to ensure reliability.
• Thermal Resistance (Rth_j-a): Expressed in °C/W, this measures how effectively heat travels from the LED junction to the ambient air. A lower value indicates better heat dissipation, which is critical for maintaining light output and longevity.
• Operating Temperature Range: The ambient temperature range (e.g., -40°C to +85°C) within which the LED is guaranteed to operate within specification.

3. Binning System Explanation

Due to manufacturing variations, LEDs are sorted into performance bins to ensure consistency for the end user.

• Wavelength/Color Temperature Binning: LEDs are grouped based on their precise dominant wavelength or CCT. This ensures a uniform color appearance when multiple LEDs are used in an array.
• Luminous Flux Binning: LEDs are sorted according to their measured light output. This allows designers to select bins that meet specific brightness requirements.
• Forward Voltage Binning: Sorting by Vf helps in designing efficient driver circuits, especially for series-connected strings, to ensure even current distribution.

The specific bin codes and their corresponding value ranges would be detailed in a full datasheet table.

4. Performance Curve Analysis

Graphical data provides deeper insight into performance under varying conditions.

• I-V (Current-Voltage) Curve: This graph shows the relationship between forward voltage and current. It is non-linear, exhibiting a turn-on voltage threshold. The curve shifts with temperature.
• Temperature Characteristics: Graphs typically show how luminous flux and forward voltage change as a function of junction temperature. Flux generally decreases as temperature rises.
• Spectral Power Distribution (SPD): A plot of relative light intensity versus wavelength. For white LEDs, this shows the blue pump LED peak and the broader phosphor-converted spectrum.

5. Mechanical and Package Information

The mechanical drawing is critical for PCB footprint design. The title suggests a 2835 package size (2.8mm x 3.5mm).

• Outline Dimensions: A detailed drawing showing the length, width, height (likely 1.2mm), and tolerances.
• Pad Layout (Footprint): The recommended copper pad pattern on the PCB, including pad size, shape, and spacing (pitch). This ensures proper soldering and thermal connection.
• Polarity Identification: Clear marking on the component body (e.g., a notch, a dot, or a cut corner) and corresponding marking on the footprint to indicate the anode (+) and cathode (-). Incorrect polarity will prevent the LED from illuminating.

6. Soldering and Assembly Guidelines

Proper handling ensures reliability and prevents damage.

• Reflow Soldering Profile: A time-temperature graph specifying the preheat, soak, reflow, and cooling phases. Key parameters include peak temperature (typically 260°C max for a few seconds) and time above liquidus. This profile is compatible with standard lead-free (SnAgCu) solder pastes.
• Precautions: Avoid mechanical stress on the lens. Use ESD (Electrostatic Discharge) precautions during handling. Ensure the soldering iron tip temperature is controlled if hand soldering is necessary.
• Storage Conditions: LEDs should be stored in a dry, dark environment at recommended temperature and humidity levels (e.g., <40°C, <60% RH) to prevent moisture absorption and material degradation.

7. Packaging and Ordering Information

• Packaging Specification: The components are typically supplied on embossed tape and reel compatible with automated pick-and-place machines. The reel size, tape width, pocket spacing, and quantity per reel are specified.
• Labeling Information: The reel label includes the part number, quantity, lot number, date code, and binning information.
• Model Numbering Rule: The full part number encodes key attributes like size, color, flux bin, voltage bin, and packaging type. For example, a code might be structured as [Series][Size][Color][Flux-Bin][Voltage-Bin][Package].

8. Application Recommendations

Typical Application Scenarios: This LED is suitable for backlighting LCDs, status indicators, decorative lighting, panel illumination, and general-purpose task lighting in compact devices.

Design Considerations:

1. Current Limiting: Always use a series resistor or a constant-current driver to control the forward current. Do not connect directly to a voltage source.
2. Thermal Management: Design the PCB with adequate thermal relief. Use thermal vias under the thermal pad (if present) to conduct heat to inner or bottom copper layers. For high-power or high-density arrays, consider additional heatsinking.
3. Optical Design: Consider the viewing angle (typically 120-140 degrees). Secondary optics like lenses or diffusers may be needed to shape the light beam.
4. ESD Protection: Incorporate ESD protection diodes on sensitive lines if the LED is in an exposed location.

9. Technical Comparison

Compared to traditional through-hole LEDs, this surface-mount device offers significant advantages:

• Size and Density: Enables much smaller and thinner end products.
• Assembly Cost: Compatible with fully automated PCB assembly, reducing labor costs.
• Performance: Often provides higher luminous efficacy and better thermal path to the PCB.
• Reliability: Solder joints are generally more robust against vibration and mechanical shock.

Compared to other SMD LED packages (e.g., 3528, 5050), the 2835 package often offers a better balance of size, light output, and thermal performance for general-purpose applications.

10. Frequently Asked Questions (FAQ)

Q1: What is the difference between luminous flux and luminous intensity?
A: Luminous flux (lumens) measures the total perceived light output in all directions. Luminous intensity (candelas) measures the light power per solid angle in a specific direction. For a wide-angle LED, flux is the more relevant metric for total light.

Q2: Can I drive this LED with a voltage higher than its forward voltage?
A: No. An LED must be driven by a controlled current. Applying a voltage source higher than Vf without current limiting will cause excessive current flow, overheating, and immediate failure.

Q3: Why does the LED's brightness decrease over time?
A> All LEDs experience lumen depreciation. The rate is primarily determined by the operating junction temperature. Operating the LED well below its maximum Tj and current ratings significantly extends its useful life.

Q4: How do I interpret the "Revision 2" and "Forever" expired period?
A> "Revision 2" means this is the second official version of this document. "Forever" for the expired period indicates this revision has no set expiration date and is valid until the manufacturer issues a new revision that supersedes it. Always check for the latest revision before finalizing a design.

11. Practical Use Case

Scenario: Designing a Status Indicator Panel
An engineer is designing a control panel that requires multiple colored status indicators (red, green, blue, white). Using this series of LEDs ensures mechanical consistency (same footprint for all colors) and simplified assembly. By selecting the appropriate flux bins for each color, visual brightness can be balanced despite the eye's different sensitivity to wavelengths. The compact 2835 size allows indicators to be placed close together. A simple design would use a microcontroller GPIO pin connected in series with a current-limiting resistor to each LED, providing independent on/off control.

12. 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. This recombination releases energy in the form of photons (light). The specific wavelength (color) of the 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 yellow phosphor; some of the blue light is converted to yellow, and the mixture of blue and yellow light is perceived as white. Different phosphor blends create different white color temperatures.

13. Technology Trends

The LED industry continues to evolve with several clear trends:

1. Increased Efficiency: Ongoing improvements in internal quantum efficiency and light extraction techniques lead to higher lumens per watt (lm/W), reducing energy consumption.
2. Improved Color Quality: Development of new phosphors and multi-color chip designs (e.g., RGB, violet+phosphor) enables higher CRI values and more consistent color rendering.
3. Miniaturization: Packages continue to shrink (e.g., micro-LEDs) while maintaining or increasing light output, enabling new applications in ultra-compact devices and high-resolution displays.
4. Smart Integration: LEDs are increasingly combined with drivers, sensors, and communication interfaces (IoT-enabled LEDs) for intelligent lighting systems.
5. Reliability and Lifetime: Advancements in materials and packaging are pushing rated lifetimes beyond 50,000 hours while maintaining higher lumen maintenance (L70, L90).

These trends are driven by demands for energy savings, new form factors in electronics, and the expansion of lighting into smart and human-centric applications.