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

1. Product Overview

This document provides a comprehensive technical overview of a high-performance white LED component. The primary function of this component is to provide efficient and reliable illumination in a wide range of electronic applications. Its core advantages include a long operational lifespan, consistent performance across various environmental conditions, and a design optimized for modern manufacturing processes. The target market encompasses general lighting solutions, backlighting for consumer electronics, automotive interior lighting, and indicator applications where reliability and energy efficiency are paramount.

2. In-Depth Technical Parameter Analysis

2.1 Photometric and Electrical Characteristics

The LED's performance is defined by several key parameters. The forward voltage (Vf) is a critical electrical parameter, typically specified at a standard test current. For this component, the nominal forward voltage is 3.2V. The power rating is 0.2W, which determines the thermal management requirements. The luminous flux output, measured in lumens (lm), defines the total visible light emitted. This parameter is often binned to ensure consistency in production batches. The correlated color temperature (CCT) for this white LED is a crucial photometric characteristic, defining whether the light appears warm, neutral, or cool white. The chromaticity coordinates (x, y) on the CIE 1931 color space diagram precisely define the color point.

2.2 Thermal Characteristics

LED performance and longevity are heavily dependent on thermal management. The junction temperature (Tj) is the temperature at the semiconductor chip itself. Maintaining a low Tj is essential for preventing accelerated lumen depreciation and color shift. The thermal resistance from the junction to the solder point (Rth j-sp) is a key metric, typically expressed in degrees Celsius per watt (°C/W). A lower value indicates more efficient heat transfer from the chip to the PCB. The maximum allowable junction temperature (Tj max) is the absolute limit for safe operation.

3. Binning System Explanation

To ensure color and performance consistency, LEDs are sorted into bins based on key parameters measured during production.

3.1 Wavelength and Color Temperature Binning

White LEDs are primarily binned by their correlated color temperature (CCT) and chromaticity coordinates. A typical binning structure might define several CCT ranges (e.g., 2700K-3000K, 3000K-3500K, 4000K-4500K, 5000K-5700K, 6000K-6500K) and ensure that the chromaticity coordinates of all LEDs within a bin fall within a small quadrilateral or ellipse on the CIE diagram, guaranteeing minimal visible color difference between units.

3.2 Luminous Flux Binning

Luminous flux output is also binned. LEDs from a single wafer can have slight variations in light output. They are sorted into flux bins (e.g., Bin A: 20-22 lm, Bin B: 22-24 lm, Bin C: 24-26 lm at a specified test current). This allows designers to select components that meet specific brightness requirements for their application.

3.3 Forward Voltage Binning

Forward voltage (Vf) is binned to aid in circuit design, particularly for applications where multiple LEDs are connected in series. Consistent Vf across a string ensures uniform current distribution and brightness. Typical Vf bins might be defined in 0.1V or 0.2V steps around the nominal voltage (e.g., 3.0V-3.1V, 3.1V-3.2V, 3.2V-3.3V).

4. Performance Curve Analysis

4.1 Current-Voltage (I-V) Characteristic Curve

The I-V curve is fundamental to LED operation. It is non-linear, similar to a diode. Below the forward voltage threshold, very little current flows. Once the threshold is exceeded, the current increases exponentially with a small increase in voltage. This characteristic necessitates the use of a constant current driver rather than a constant voltage source for stable operation. The curve also shows the dynamic resistance of the LED at its operating point.

4.2 Temperature Dependency

LED characteristics are temperature-sensitive. As the junction temperature increases, the forward voltage typically decreases slightly. More significantly, the luminous flux output decreases. This relationship is often plotted as relative luminous flux versus junction temperature. High-quality LEDs maintain a higher percentage of their output at elevated temperatures. The spectral power distribution may also shift slightly with temperature, affecting the color point.

4.3 Spectral Power Distribution

The spectral power distribution (SPD) graph shows the intensity of light emitted at each wavelength. For a white LED based on a blue chip with a phosphor coating, the SPD features a sharp peak in the blue region (from the chip) and a broader emission band in the yellow/green/red region (from the phosphor). The exact shape of the SPD determines the Color Rendering Index (CRI), which indicates how naturally colors appear under the light.

5. Mechanical and Package Information

5.1 Dimensional Outline Drawing

The component features a standard surface-mount device (SMD) package. The dimensions are 2.8mm in length, 3.5mm in width, and 1.2mm in height. A detailed mechanical drawing provides top, side, and bottom views with all critical dimensions and tolerances clearly marked, including the lens shape and the location of the cathode/anode markers.

5.2 Pad Layout and Solder Mask Design

The recommended land pattern (footprint) for PCB design is provided. It specifies the pad dimensions, spacing, and solder mask opening. A well-designed pad layout ensures proper solder joint formation during reflow, good thermal conduction to the PCB for heat dissipation, and prevents solder bridging. The document includes a table with the X and Y coordinates for the pad centers.

5.3 Polarity Identification

Clear polarity identification is crucial for correct installation. The cathode is typically marked. Common marking methods include a green dot on the cathode side, a chamfered corner on the package corresponding to the cathode, or a "T" or other symbol printed on the lens. The bottom view drawing explicitly labels the anode and cathode pads.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A detailed reflow profile is essential for reliable assembly. The profile specifies the preheat temperature ramp rate, the soak (preflow) temperature and duration, the time above liquidus (TAL), the peak temperature, and the cooling rate. For this LED, the maximum peak body temperature must not exceed 260°C, and the time above 240°C should be limited. The profile should be verified using a thermocouple attached to the LED body.

6.2 Precautions and Handling

LEDs are sensitive to electrostatic discharge (ESD). Assembly should be performed in an ESD-protected environment using grounded equipment. Avoid mechanical stress on the lens. Do not clean the LED with ultrasonic cleaners after soldering, as this can damage the internal structure. Use no-clean flux where possible to avoid residue that might affect light output or cause corrosion.

6.3 Storage Conditions

To maintain solderability and prevent moisture absorption (which can cause "popcorning" during reflow), LEDs should be stored in their original moisture barrier bags with desiccant. The storage environment should be below 30°C and 60% relative humidity. If the bags have been opened for more than a specified time (e.g., 168 hours), components may require baking before use according to the Moisture Sensitivity Level (MSL) rating, typically MSL 2a or 3.

7. Packaging and Ordering Information

7.1 Packaging Specifications

The LEDs are supplied on embossed carrier tapes wound onto reels. Standard reel quantities are 2000 or 4000 pieces per reel. The tape width, pocket dimensions, and reel diameter are specified. The cover tape peel strength is defined to ensure reliable pick-and-place operation by automated assembly machines.

7.2 Label Information

Each reel has a label containing critical information: part number, quantity, date code, lot number, bin codes for flux, CCT, and Vf, and the manufacturer's details. The date code and lot number are essential for traceability.

7.3 Part Numbering System

The part number is a code that encapsulates the key specifications. It typically includes fields representing the package size (e.g., 2835), color (e.g., W for white), CCT bin (e.g., 4A for 4000K), flux bin (e.g., H for a specific lumen range), and forward voltage bin (e.g., F for 3.1-3.2V). Understanding this nomenclature is key to ordering the correct component.

8. Application Recommendations

8.1 Typical Application Scenarios

This LED is suitable for a broad spectrum of applications. In general lighting, it can be used in LED bulbs, tubes, and panel lights. For backlighting, it serves in LCD displays for TVs, monitors, and automotive dashboards. It is also ideal for architectural accent lighting, signage, and portable lighting devices due to its efficiency and compact size.

8.2 Design Considerations

Successful implementation requires careful design. Always use a constant current LED driver matched to the forward voltage and desired current. Implement proper thermal management by providing adequate copper area on the PCB (thermal pads) and, if necessary, using a metal-core PCB (MCPCB) or heatsink. Consider optical design elements like diffusers or lenses to achieve the desired beam angle and light distribution. Account for forward voltage variation and thermal effects when designing series/parallel arrays.

9. Technical Comparison and Differentiation

Compared to earlier generation LEDs or alternative technologies, this component offers distinct advantages. Its efficacy (lumens per watt) is higher, leading to greater energy savings. The color consistency (tight binning) is superior, reducing the need for manual sorting in production. The package design offers better thermal performance, allowing for higher drive currents or longer lifespan at standard currents. The reliability under thermal stress and humidity is typically validated through stringent testing like LM-80, providing confidence for long-term applications.

10. Frequently Asked Questions (FAQ)

Q: What is the typical lifespan of this LED?

A: The lifespan, often defined as L70 (time to 70% of initial lumen output), depends heavily on operating conditions (drive current and junction temperature). Under recommended operating conditions, it can exceed 50,000 hours.

Q: Can I drive this LED directly with a 3.3V supply?

A: No. The forward voltage is approximately 3.2V, but it is a diode with a dynamic resistance. A small variation in supply voltage will cause a large change in current, potentially damaging the LED. A constant current driver or a current-limiting resistor with a higher voltage supply is required.

Q: How do I interpret the bin codes on the label?

A: Refer to the binning section of this datasheet. Each letter/number in the part number or bin code field corresponds to a specific range for flux, CCT, or Vf. Cross-reference these codes with the binning tables provided.

Q: Is the lens made of silicone or epoxy?

A: High-performance LEDs like this one typically use silicone-based lenses due to their superior resistance to yellowing and thermal degradation compared to traditional epoxy, ensuring stable light output and color over time.

11. Practical Application Case Studies

11.1 Case Study: Linear LED Fixture

In a 4-foot LED tube light designed to replace fluorescent tubes, 120 pieces of this LED are mounted on a narrow, elongated metal-core PCB (MCPCB). They are arranged in a series-parallel configuration powered by a constant current driver embedded in the tube ends. The MCPCB efficiently transfers heat to the aluminum housing. The tight CCT and flux binning ensure uniform brightness and color along the entire length of the tube, a critical aesthetic requirement. The design achieves an efficacy of over 120 lm/W and a lifespan of 50,000 hours.

11.2 Case Study: Automotive Interior Light

For a dome light assembly, a small cluster of 3-5 LEDs is used. The design challenge involves operating reliably over the wide automotive temperature range (-40°C to +85°C ambient). The LED's stable performance across temperature, combined with a simple linear current regulator circuit, provides a robust solution. The light is diffused through a molded plastic lens to create a soft, even illumination. The low power consumption minimizes load on the vehicle's electrical system.

12. Operating Principle Introduction

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 (the p-n junction). When electrons and holes recombine, energy is released in the form of photons (light). The wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor materials used in the active region. A white LED is created by coating a blue or ultraviolet LED chip with a phosphor material. The phosphor absorbs some of the blue/UV light and re-emits it as yellow, green, and red light. The mixture of the remaining blue light and the phosphor-emitted light is perceived as white by the human eye.

13. Technology Trends and Developments

The LED industry continues to evolve rapidly. Key trends include the ongoing improvement of efficacy, pushing beyond 200 lm/W in laboratory settings. There is a strong focus on improving color quality, with high-CRI (Ra>90, R9>50) LEDs becoming more common for applications requiring accurate color rendering. Miniaturization continues with even smaller package sizes like 2016 and 1515. Novel phosphor systems, including quantum dots, are being developed to achieve wider color gamuts for display applications. Furthermore, there is significant research into human-centric lighting, tuning the spectral output to influence circadian rhythms and well-being. Reliability and lifetime under high-temperature, high-humidity conditions are also areas of continuous improvement to meet the demands of automotive and outdoor lighting.