SMD LED White Diffused Dual-Color (Green/Yellow) Datasheet - Package Dimensions - Forward Voltage 1.8-3.4V - Power Dissipation 72-102mW - English Technical Document

1. Product Overview

This document details the specifications for a white diffused Surface-Mount Device (SMD) Light Emitting Diode (LED) designed for automated printed circuit board (PCB) assembly. The component is characterized by its compact size, making it suitable for space-constrained applications. It is engineered for compatibility with high-volume, automated placement systems and standard infrared (IR) reflow soldering processes, adhering to industry standards for lead-free assembly.

1.1 Core Features and Target Market

The LED is designed with several key features that enhance its applicability in modern electronics. It is compliant with RoHS (Restriction of Hazardous Substances) directives. It is supplied in industry-standard 8mm tape on 7-inch reels, facilitating efficient handling by pick-and-place machines. The device is I.C. compatible and has been preconditioned to JEDEC Level 3 moisture sensitivity, ensuring reliability during the soldering process. Its primary target markets include telecommunications equipment, office automation devices, home appliances, and industrial control systems. Typical applications range from status indicators and backlighting for front panels to signal and symbol illumination.

2. Technical Parameters: In-Depth Objective Interpretation

The performance of the LED is defined by a comprehensive set of electrical and optical parameters measured at an ambient temperature (Ta) of 25°C.

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. For the Yellow LED, the maximum power dissipation is 72 mW, while for the Green LED, it is 102 mW. Both colors share a maximum continuous DC forward current (IF) of 30 mA. A higher peak forward current of 80 mA is permissible under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). The device is rated for operation within a temperature range of -40°C to +85°C and can be stored in environments from -40°C to +100°C.

2.2 Electrical and Optical Characteristics

The core performance metrics are specified under a test condition of IF = 20mA. The luminous intensity (Iv) for the Yellow LED ranges from a minimum of 710 mcd to a maximum of 1800 mcd. The Green LED offers a higher output, ranging from 1120 mcd to 2800 mcd. The viewing angle (2θ1/2), defined as the full angle at which intensity is half the axial value, is typically 120 degrees for both, indicating a wide, diffused emission pattern. The peak emission wavelength (λP) is 590 nm (Yellow) and 524 nm (Green), with the dominant wavelength (λd) specified within ranges of 585-595 nm and 518-528 nm, respectively. The forward voltage (VF) varies by color: Yellow LEDs have a VF between 1.8V and 2.4V, while Green LEDs operate between 2.6V and 3.4V at 20mA. The maximum reverse current (IR) is 10 μA at a reverse voltage (VR) of 5V, noting that the device is not designed for reverse bias operation.

3. Bin Rank System Explanation

To ensure consistency in luminous output, the LEDs are sorted into intensity bins. Each bin has a defined minimum and maximum luminous intensity value, with a tolerance of +/-11% applied within each bin.

3.1 Luminous Intensity Binning

For Yellow LEDs, the bin codes are V1 (710-900 mcd), V2 (900-1120 mcd), W1 (1120-1400 mcd), and W2 (1400-1800 mcd). For Green LEDs, the bins are W1 (1120-1400 mcd), W2 (1400-1800 mcd), X1 (1800-2240 mcd), and X2 (2240-2800 mcd). This binning allows designers to select components that meet specific brightness requirements for their application.

4. Performance Curve Analysis

While specific graphical data is referenced in the source document, typical performance curves for such devices generally illustrate the relationship between forward current and luminous intensity (I-V curve), the variation of forward voltage with temperature, and the spectral power distribution showing the peak wavelength and spectral half-width. These curves are essential for understanding device behavior under non-standard operating conditions and for precise circuit design.

5. Mechanical and Package Information

5.1 Package Dimensions and Pin Assignment

The LED comes in a standard SMD package. The white diffused lens houses two semiconductor chips. The pin assignment is clearly defined: pins 1 and 2 are for the Green (InGaN) LED, and pins 3 and 4 are for the Yellow (AlInGaP) LED. All dimensional drawings specify measurements in millimeters, with a general tolerance of ±0.2 mm unless otherwise noted. This information is critical for PCB footprint design.

5.2 Recommended PCB Attachment Pad Layout

A diagram is provided showing the recommended copper pad pattern on the PCB for infrared or vapor phase reflow soldering. Adhering to this layout ensures proper solder joint formation, thermal management, and mechanical stability of the component after assembly.

6. Soldering and Assembly Guidelines

6.1 IR Reflow Soldering Profile

A suggested reflow soldering profile compliant with J-STD-020B for lead-free processes is provided. Key parameters include a pre-heat temperature of 150-200°C, a pre-heat time up to 120 seconds maximum, a peak temperature not exceeding 260°C, and a time above liquidus (or at peak) limited to 10 seconds maximum. It is emphasized that the optimal profile depends on the specific PCB design, solder paste, and oven, and the provided profile should be used as a generic target validated for the specific assembly line.

6.2 Manual Soldering

If manual soldering with an iron is necessary, the maximum recommended iron tip temperature is 300°C, with a soldering time not exceeding 3 seconds per joint. This should be performed only once to prevent thermal damage to the LED package.

6.3 Storage Conditions

Proper storage is vital for maintaining solderability. Unopened moisture-proof bags (with desiccant) should be stored at ≤30°C and ≤70% RH, with a shelf life of one year. Once opened, LEDs should be stored at ≤30°C and ≤60% RH. Components removed from their original packaging should undergo IR reflow within 168 hours. If this window is exceeded, a bake-out at approximately 60°C for at least 48 hours is recommended before soldering to remove absorbed moisture and prevent \"popcorning\" during reflow.

6.4 Cleaning

If cleaning after soldering is required, only specified alcohol-based 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 may damage the package material or the lens.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The LEDs are packaged in 8mm wide embossed carrier tape wound on 7-inch (178mm) diameter reels. Each reel contains 2000 pieces. The tape is sealed with a top cover. Packaging follows ANSI/EIA 481 specifications, which dictate parameters like pocket spacing and reel dimensions for compatibility with automated equipment. A minimum packing quantity of 500 pieces is available for remainder orders.

8. Application Suggestions

8.1 Typical Application Scenarios

This dual-color LED is ideal for applications requiring multi-status indication from a single component footprint. Examples include power/charge status indicators (e.g., green for \"on\" or \"fully charged,\" yellow for \"standby\" or \"charging\"), mode selection feedback on consumer electronics, and backlighting for symbols or icons on control panels. Its wide viewing angle makes it suitable for applications where visibility from off-axis angles is important.

8.2 Design Considerations

Current Driving: LEDs are current-driven devices. A series current-limiting resistor must be used for each color channel when driven from a voltage source. The resistor value is calculated using Ohm's Law: R = (Vsource - VF_LED) / IF, where VF_LED is the forward voltage of the specific LED color at the desired current (e.g., 20mA). Using the maximum VF from the datasheet ensures the current does not exceed the limit even with component variation.
Thermal Management: While power dissipation is low, ensuring adequate PCB copper area around the thermal pads (if any) or general trace width helps dissipate heat, maintaining LED performance and longevity, especially in high ambient temperature environments.
Circuit Layout: Keep the current drive paths for the two colors separate to allow independent control.

9. Technical Comparison and Differentiation

The key differentiating feature of this component is the integration of two distinct LED colors (Green and Yellow) within a single, compact white diffused package. This saves PCB space compared to using two separate single-color LEDs. The wide 120-degree viewing angle provided by the diffused lens offers uniform illumination ideal for panel indicators. The device's compatibility with standard SMD assembly processes (JEDEC Level 3 MSL, lead-free reflow) ensures it can be dropped into existing high-volume manufacturing lines without requiring special handling or process changes.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive both LED colors simultaneously at their maximum current?
A: No. The Absolute Maximum Ratings specify power dissipation limits for each color individually (72mW for Yellow, 102mW for Green). Driving both at 30mA DC would result in a total power that likely exceeds the package's thermal capability, potentially leading to overheating and reduced lifespan. Consult the derating curves (if available) or operate at lower currents for simultaneous use.
Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (λP) is the wavelength at which the emitted optical power is highest. Dominant wavelength (λd) is the single wavelength of monochromatic light that would appear to have the same color as the LED's output to a standard human observer. λd is derived from the CIE chromaticity diagram and is often more relevant for color specification.
Q: The forward voltage range is quite wide (e.g., 2.6V-3.4V for Green). How does this affect my circuit design?
A: This variation is typical for LEDs due to semiconductor manufacturing tolerances. Your current-limiting circuit must be designed to handle the worst-case scenario. Use the maximum VF (3.4V) in your resistor calculation to ensure the current never exceeds the desired value (e.g., 20mA) even if you receive an LED with the highest VF. This will result in slightly dimmer operation for LEDs with lower VF, but it is the safe design approach.

11. Practical Application Case Study

Scenario: Designing a Dual-Status Charging Indicator for a Portable Device.
A common use case is an indicator that shows red for charging, yellow for nearly full, and green for fully charged. While this specific LED does not include red, a similar design principle applies. Two independent driver circuits (e.g., GPIO pins from a microcontroller with series resistors) would control the Yellow and Green LEDs. The firmware would sequence the colors: Green off/Yellow on during active charging, then switch to Green on/Yellow off when charging is complete. The white diffused lens ensures the light is evenly blended and visible from a wide angle, providing clear user feedback. The SMD package allows this functionality in a minimal footprint on the device's densely packed PCB.

12. Operating Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that emit light when an electric current passes through them. This phenomenon is called electroluminescence. When a forward voltage is applied across the p-n junction, electrons from the n-type material recombine with holes from the p-type material, releasing energy in the form of photons (light). The specific color of the light is determined by the energy bandgap of the semiconductor material used. In this component, the Green light is produced by an Indium Gallium Nitride (InGaN) chip, and the Yellow light is produced by an Aluminum Indium Gallium Phosphide (AlInGaP) chip. The white diffused epoxy lens encapsulates the chips, providing mechanical protection, shaping the light output beam to a wide angle, and diffusing the light to reduce glare and create a uniform appearance.

13. Industry Trends and Developments

The trend in SMD LEDs for indicator applications continues towards higher efficiency (more light output per unit of electrical power), smaller package sizes for ever-denser electronics, and increased integration. Multi-color and RGB LEDs in single packages are becoming more common, enabling full-color programmability. There is also a focus on improving color consistency and tightening binning specifications to meet the demands of applications where color matching is critical. Furthermore, advancements in packaging materials aim to enhance reliability under higher temperature reflow profiles and improve long-term lumen maintenance. The component described fits within these broader trends by offering dual-color functionality in a standardized, reliable SMD format suitable for automated, high-reliability manufacturing.