SMD LED Green AlInGaP Datasheet - 3.0x1.5x1.1mm - 2.4V - 75mW - English Technical Document

1. Product Overview

This document details the specifications for a high-performance, surface-mount LED utilizing an AlInGaP (Aluminum Indium Gallium Phosphide) chip to produce green light. The device is designed for applications requiring high luminous intensity and reliability in a compact, industry-standard package. Its primary advantages include ultra-bright output, compatibility with automated assembly processes, and adherence to RoHS and green product standards. The target market includes consumer electronics, industrial indicators, automotive interior lighting, and general illumination modules where consistent color and brightness are critical.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The device is rated for a maximum continuous forward current (DC) of 30 mA at an ambient temperature (Ta) of 25°C. The power dissipation is limited to 75 mW. For pulsed operation, a peak forward current of 80 mA is permissible under a 1/10 duty cycle with a 0.1ms pulse width. The maximum reverse voltage is 5 V. The operating and storage temperature range is specified from -55°C to +85°C. The LED can withstand wave or infrared soldering at 260°C for 5 seconds, and vapor phase soldering at 215°C for 3 minutes. A derating factor of 0.4 mA/°C applies for the forward current above 50°C ambient temperature.

2.2 Electro-Optical Characteristics

Measured at Ta=25°C and a forward current (IF) of 20 mA, the key parameters are as follows. The luminous intensity (IV) has a typical value of 600 mcd, with a minimum of 180 mcd. The viewing angle (2θ1/2), defined as the full angle at half intensity, is 25 degrees. The peak emission wavelength (λP) is typically 574 nm, while the dominant wavelength (λd), which defines the perceived color, is typically 571 nm. The spectral line half-width (Δλ) is 15 nm. The forward voltage (VF) ranges from 2.0 V to 2.4 V at 20 mA. The reverse current (IR) is a maximum of 10 μA at a reverse voltage (VR) of 5 V. The junction capacitance (C) is 40 pF measured at 0 V and 1 MHz.

3. Binning System Explanation

To ensure consistency in production, LEDs are sorted into bins based on key parameters. This allows designers to select parts that meet specific application requirements for voltage, brightness, and color.

3.1 Forward Voltage Binning

Forward voltage is binned in 0.1 V steps. Bin codes range from 4 (1.90V - 2.00V) to 8 (2.30V - 2.40V). The tolerance within each bin is ±0.1 V. This is crucial for current-limiting resistor calculation and ensuring uniform brightness in parallel arrays.

3.2 Luminous Intensity Binning

Luminous intensity is binned on a logarithmic scale. Bin codes are: S (180-280 mcd), T (280-450 mcd), U (450-710 mcd), V (710-1120 mcd), and W (1120-1800 mcd). A tolerance of ±15% applies within each bin. This allows selection for different brightness requirements.

3.3 Dominant Wavelength Binning

Dominant wavelength, defining the green color point, is binned in 3 nm steps. Bin codes are C (567.5-570.5 nm), D (570.5-573.5 nm), and E (573.5-576.5 nm). The tolerance is ±1 nm per bin, ensuring tight color consistency for applications like full-color displays or status indicators where color matching is vital.

4. Performance Curve Analysis

While specific graphical curves are referenced in the datasheet (Fig.1, Fig.6), their implications can be described. The relationship between forward current (IF) and luminous intensity (IV) is typically super-linear, meaning intensity increases more than proportionally with current up to a point, after which efficiency drops. The forward voltage (VF) has a negative temperature coefficient; it decreases slightly as the junction temperature increases. The spectral distribution curve shows a narrow peak around 574 nm, which is characteristic of AlInGaP technology, offering high color purity and efficiency in the green-yellow region compared to older technologies like GaP.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The LED is housed in an industry-standard surface-mount package. Key dimensions include a body size of approximately 3.0mm in length, 1.5mm in width, and 1.1mm in height (typical for this package type). The device features a dome lens which helps in achieving the specified 25-degree viewing angle by shaping the light output. All dimensional tolerances are ±0.10 mm unless otherwise specified.

5.2 Polarity Identification and Pad Design

The cathode is typically identified by a visual marker on the package, such as a notch, dot, or cut corner. Recommended solder pad dimensions are provided to ensure proper soldering and mechanical stability. The pad design accounts for thermal relief and prevents tombstoning during reflow. A land pattern that slightly extends beyond the package footprint is usually suggested for reliable solder fillet formation.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profiles

Two suggested reflow profiles are provided: one for standard SnPb solder process and one for Pb-free (e.g., SnAgCu) solder process. The Pb-free profile requires a higher peak temperature, typically up to 260°C, with a time above liquidus (TAL) carefully controlled. The pre-heat ramp rate and peak temperature duration (5 seconds max at 260°C) are critical to prevent thermal shock to the epoxy lens and the semiconductor die.

6.2 Storage and Handling

LEDs should be stored in conditions not exceeding 30°C and 70% relative humidity. If removed from the original moisture-barrier bag, they should be reflow-soldered within one week. For longer storage outside the original packaging, storage in a sealed container with desiccant or in a nitrogen atmosphere is recommended. Components stored for more than a week should be baked at approximately 60°C for at least 24 hours prior to assembly to remove absorbed moisture and prevent \"popcorning\" during reflow.

6.3 Cleaning

Only specified cleaning agents should be used. Isopropyl alcohol (IPA) or ethyl alcohol are recommended. The LED should be immersed at normal temperature for less than one minute. Harsh or unspecified chemicals can damage the epoxy lens, leading to clouding or cracking.

7. Packaging and Ordering Information

The LEDs are supplied on 8mm wide embossed carrier tape, wound onto 7-inch (178mm) diameter reels. Standard reel quantity is 1500 pieces. A minimum packing quantity of 500 pieces is available for remainder quantities. The tape and reel specifications comply with ANSI/EIA 481-1-A-1994. The top cover tape seals empty pockets. The maximum allowable number of consecutive missing components on the reel is two.

8. Application Recommendations

8.1 Typical Application Scenarios

This LED is suitable for backlighting small LCDs, status and indicator lights in consumer and industrial equipment, automotive dashboard illumination, decorative lighting, and panel-mounted indicators. Its high brightness makes it effective even in moderately lit environments.

3.2 Design Considerations

Drive Circuit: LEDs are current-driven devices. To ensure uniform brightness when using multiple LEDs in parallel, it is strongly recommended to use a separate current-limiting resistor in series with each LED (Circuit Model A). Driving multiple LEDs in parallel from a single resistor (Circuit Model B) is not recommended due to variations in individual LED forward voltage (VF), which can cause significant differences in current and thus brightness.

Thermal Management: While the package is small, the 75 mW power dissipation limit must be respected, especially at high ambient temperatures. The derating curve must be followed. Adequate PCB copper area around the thermal pads can help dissipate heat.

ESD Protection: The AlInGaP chip is sensitive to electrostatic discharge (ESD). Handling precautions include using grounded wrist straps, anti-static mats, and ionizers. All equipment and work surfaces must be properly grounded.

9. Technical Comparison

Compared to traditional GaP (Gallium Phosphide) green LEDs, AlInGaP technology offers significantly higher luminous efficiency and brightness. It also provides better color saturation (narrower spectral width) and stability over temperature and current variations. Compared to InGaN (Indium Gallium Nitride) blue/white LEDs with phosphor conversion for green, true green AlInGaP LEDs generally offer higher efficacy in the pure green spectrum, making them preferable for applications where specific green color points or maximum efficiency in green are required.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED at 30 mA continuously?

A: Yes, but only at or below an ambient temperature of 25°C. As temperature rises, the maximum allowable current decreases according to the derating factor of 0.4 mA/°C above 50°C. For reliable long-term operation, driving at 20 mA or less is common practice.

Q: Why is a separate resistor needed for each parallel LED?

A: The forward voltage (VF) has a production tolerance and a negative temperature coefficient. Small differences in VF can cause large imbalances in current sharing when LEDs are connected in parallel to a single voltage source with one resistor. This leads to uneven brightness and potential overstress of one device.

Q: What is the difference between peak wavelength and dominant wavelength?

A: Peak wavelength (λP) is the wavelength at which the spectral power distribution is maximum. Dominant wavelength (λd) is derived from the CIE chromaticity diagram and represents the single wavelength of the spectrum that matches the perceived color of the LED. λd is more relevant for color specification.

Q: How do I interpret the bin codes when ordering?

A: You must specify the required bin codes for Forward Voltage (e.g., Bin 5), Luminous Intensity (e.g., Bin T), and Dominant Wavelength (e.g., Bin D) to get parts that meet your circuit's voltage drop, brightness, and color requirements precisely.

11. Practical Design and Usage Case

Case: Designing a Multi-LED Status Panel

A designer needs 10 uniform green indicators on a control panel. They select this LED with bins: Voltage=6 (2.1-2.2V), Intensity=T (280-450 mcd), Wavelength=D (570.5-573.5 nm). The supply voltage is 5V. For each LED, a series resistor is calculated using R = (Vsupply - Vf_typical) / If. Using Vf_typ=2.15V and If=20mA, R = (5 - 2.15) / 0.02 = 142.5 Ω. A standard 150 Ω resistor is chosen, resulting in a current of ~19mA. This ensures all 10 LEDs have nearly identical current and brightness, despite minor Vf variations within the bin, because each has its own current-setting resistor. The 25-degree viewing angle is suitable for the panel's intended viewing distance.

12. Technology Principle Introduction

AlInGaP is a III-V compound semiconductor material. The color of light emitted is determined by the bandgap energy of the active region, which is tuned by adjusting the ratios of Aluminum, Indium, Gallium, and Phosphorus. A higher Aluminum content increases the bandgap, shifting emission toward shorter wavelengths (green/yellow), while more Indium decreases the bandgap, shifting toward longer wavelengths (orange/red). This LED uses a specific AlInGaP composition to achieve emission in the green spectrum (~571 nm). When a forward voltage is applied, electrons and holes recombine in the active region, releasing energy in the form of photons (light). The dome-shaped epoxy lens serves to extract and direct this light efficiently.

13. Technology Development Trends

The trend in LED technology continues toward higher efficiency (more lumens per watt), increased power density, and improved color rendering and consistency. For AlInGaP materials, research focuses on improving internal quantum efficiency and light extraction efficiency, potentially through advanced chip structures like thin-film or flip-chip designs. There is also ongoing development to expand the color gamut and stability of AlInGaP across its wavelength range. Furthermore, integration with smart drivers and miniaturization for micro-display applications are active areas of development. The drive for higher reliability and performance in automotive and specialized industrial applications pushes advancements in packaging materials and thermal management for these devices.