SMD LED Diffused Lens Dual Color (Red/Green) - Package Dimensions - Forward Voltage 1.8-2.4V - Power Dissipation 72mW - English Datasheet

1. Product Overview

This document details the specifications for a surface-mount device (SMD) light-emitting diode (LED) featuring a dual-color (Red and Green) configuration within a single package. The device utilizes a diffused lens, which helps in achieving a wider and more uniform light distribution, making it suitable for applications requiring indicator functions or backlighting with color differentiation. The LED is constructed using AlInGaP (Aluminum Indium Gallium Phosphide) technology for both color chips, known for its efficiency and brightness. It is designed to be compatible with automated pick-and-place equipment and standard infrared reflow soldering processes, aligning with modern electronics manufacturing workflows.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The absolute maximum ratings define the stress limits beyond which permanent damage to the device may occur. These values are specified at an ambient temperature (Ta) of 25°C. For the red and green chips, the continuous DC forward current is rated at 30 mA. The peak forward current, applicable under pulsed conditions (1/10 duty cycle, 0.1ms pulse width), is 80 mA. The maximum permissible reverse voltage is 5 V. The total power dissipation for each chip is 72 mW. The device is rated for operation within a temperature range of -40°C to +85°C and can be stored in environments ranging from -40°C to +100°C.

2.2 Electrical and Optical Characteristics

The key performance parameters are measured at Ta=25°C and a standard test current (IF) of 20 mA.

• Luminous Intensity (Iv): For the red chip, the minimum luminous intensity is 112.0 mcd, with a maximum of 280.0 mcd. The green chip has a minimum of 71.0 mcd and a maximum of 224.0 mcd. The typical value is not specified, indicating performance is managed through binning.
• Viewing Angle (2θ1/2): The typical full viewing angle is 120 degrees, meaning the off-axis angle where intensity drops to half its on-axis value is 60 degrees. This wide angle is characteristic of a diffused lens.
• Wavelength: The red chip has a typical peak emission wavelength (λP) of 639 nm and a dominant wavelength (λd) of 631 nm. The green chip has a typical λP of 574 nm and λd of 571 nm. The spectral line half-width (Δλ) is 20 nm for red and 15 nm for green.
• Forward Voltage (VF): The forward voltage for both colors ranges from a minimum of 1.8 V to a maximum of 2.4 V at 20 mA, with a noted tolerance of ±0.1 V.
• Reverse Current (IR): The maximum reverse current is 10 μA when a reverse voltage (VR) of 5 V is applied.

3. Binning System Explanation

To ensure consistency in applications, the LEDs are sorted into bins based on their luminous intensity. This allows designers to select parts that meet specific brightness requirements.

3.1 Red Color Binning

The luminous intensity for the red chip is categorized into four bins: R1 (112.0-140.0 mcd), R2 (140.0-180.0 mcd), S1 (180.0-224.0 mcd), and S2 (224.0-280.0 mcd).

3.2 Green Color Binning

The green chip uses five bins: Q1 (71.0-90.0 mcd), Q2 (90.0-112.0 mcd), R1 (112.0-140.0 mcd), R2 (140.0-180.0 mcd), and S1 (180.0-224.0 mcd). A tolerance of ±11% is applied to each intensity bin.

4. Performance Curve Analysis

The datasheet references typical electrical and optical characteristic curves. While the specific graphs are not provided in the text, such curves typically illustrate the relationship between forward current and forward voltage (IV curve), the variation of luminous intensity with forward current, the temperature dependence of forward voltage and luminous intensity, and the spectral power distribution. Analyzing these curves is crucial for understanding device behavior under non-standard conditions, such as different drive currents or ambient temperatures.

5. Mechanical and Package Information

5.1 Device Dimensions and Pin Assignment

The LED conforms to an EIA standard package outline. The specific dimensional drawing is referenced. The pin assignment for the dual-color LED is as follows: Pins 1 and 2 are assigned to the red chip, and pins 3 and 4 are assigned to the green chip. All dimensions are in millimeters, with a general tolerance of ±0.2 mm unless otherwise specified.

5.2 Tape and Reel Packaging

The components are supplied in 8mm tape on 7-inch diameter reels, compatible with automated assembly. Each reel contains 2000 pieces. The packaging follows EIA-481-1-B specifications. Notes specify that empty pockets are sealed, the minimum order quantity for remainders is 500 pieces, and a maximum of two consecutive missing components are allowed per reel.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

For lead-free soldering processes, an infrared reflow profile compliant with J-STD-020B is recommended. Key parameters include a pre-heat temperature of 150-200°C, a pre-heat time of up to 120 seconds maximum, a peak temperature not exceeding 260°C, and a time above liquidus (or at peak) of 10 seconds maximum. Reflow should be performed a maximum of two times.

6.2 Hand Soldering

If using a soldering iron, the tip temperature should not exceed 300°C, and the soldering time per lead should be limited to 3 seconds maximum. Hand soldering should be performed only once.

6.3 Storage and Handling

For unopened moisture-proof bags with desiccant, LEDs should be stored at ≤30°C and ≤70% RH and used within one year. Once opened, the storage environment should be ≤30°C and ≤60% RH. Components removed from their original packaging should undergo IR reflow within 168 hours. For storage beyond this period, baking at approximately 60°C for at least 48 hours before assembly is recommended.

6.4 Cleaning

If cleaning is necessary, only specified solvents like ethyl alcohol or isopropyl alcohol should be used. The LED should be immersed at normal temperature for less than one minute. Unspecified chemicals must be avoided as they may damage the package.

7. Application Suggestions

7.1 Typical Application Scenarios

This dual-color LED is well-suited for status indicators, power/charge indicators, backlighting for icons or symbols requiring two-color states (e.g., on/off, active/standby, go/wait), and consumer electronics displays. The diffused lens makes it ideal for applications where a wide viewing angle and soft, non-glaring light are desired.

7.2 Design Considerations

Drive Method: LEDs are current-operated devices. To ensure uniform brightness, especially when multiple LEDs are connected in parallel, a current-limiting resistor must be used in series with each LED or each color channel. The resistor value is calculated based on the supply voltage (Vcc), the desired forward current (IF, typically 20 mA), and the forward voltage (VF) of the LED: R = (Vcc - VF) / IF.

Thermal Management: While power dissipation is relatively low, ensuring adequate PCB layout for heat dissipation is good practice, especially in high ambient temperature environments or when driving near maximum ratings.

Polarity and Placement: Correct orientation according to the pin assignment diagram is critical. The recommended PCB attachment pad layout should be followed to ensure proper soldering and mechanical stability.

8. Technical Comparison and Differentiation

The key differentiators of this component include its dual-color capability in a single SMD package, saving board space compared to using two discrete LEDs. The use of AlInGaP technology typically offers higher efficiency and better performance stability over temperature compared to some other material systems for red and amber colors. The 120-degree viewing angle provided by the diffused lens offers broader visibility. Compliance with RoHS and compatibility with lead-free reflow processes make it suitable for modern, environmentally conscious manufacturing.

9. Frequently Asked Questions (FAQs)

Q: Can I drive the red and green chips simultaneously to create a yellow/orange color?

A: While electrically possible, mixing colors by driving both chips requires careful current control to achieve a specific chromaticity. The datasheet does not provide mixed-color specifications, so results may vary. For dedicated color mixing, a dedicated RGB LED with characterized color coordinates is recommended.

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 in display applications.

Q: How do I select the correct bin for my application?

A> Choose a bin based on the minimum brightness required for your design under worst-case conditions (e.g., maximum forward voltage, high temperature). Using a bin with a higher minimum intensity provides a design margin. Consistency across multiple units in a product is achieved by specifying a single bin code.

10. Practical Application Case

Scenario: Dual-Status Indicator for a Portable Device

In a handheld medical monitor, this LED can be used to indicate battery status. When the battery is charging, the green LED illuminates. When the battery is low, the red LED illuminates. A microcontroller GPIO pin can control each color via a simple transistor switch circuit with a series resistor. The wide viewing angle ensures the status is visible from various angles. The design must account for the forward voltage difference and ensure the current-limiting resistor is calculated separately for each color if driven from the same voltage rail, though their VF ranges are similar in this case.

11. Operating Principle Introduction

Light emission in an AlInGaP LED is based on electroluminescence. When a forward voltage is applied across the p-n junction, electrons and holes are injected into the active region. Their recombination releases energy in the form of photons (light). The specific wavelength (color) of the emitted light is determined by the bandgap energy of the semiconductor materials in the active region. A diffused lens, typically made of epoxy or silicone with scattering particles, is molded over the chip. This lens scatters the light, broadening the emission pattern from a narrow beam to a wide, Lambertian-like distribution, thereby increasing the effective viewing angle.

12. Technology Trends

The general trend in SMD indicator LEDs continues toward higher efficiency (more lumens per watt), allowing for the same brightness at lower currents, which reduces power consumption and heat generation. There is also a drive for miniaturization while maintaining or improving optical performance. Enhanced reliability under harsh environmental conditions (temperature, humidity) is a constant focus. Furthermore, integration of multiple colors and even built-in control ICs (like addressable RGB LEDs) within standard package footprints is becoming more common, offering greater functionality per unit area on the PCB.