SMD LED Diffused Yellow Datasheet - AlInGaP - 120° Viewing Angle - 50mA - 3550mcd - English Technical Document

1. Product Overview

This document provides the complete technical specifications for a surface-mount device (SMD) light-emitting diode (LED). The device features a diffused lens and utilizes an Aluminum Indium Gallium Phosphide (AlInGaP) semiconductor material to produce yellow light. It is designed for compatibility with automated assembly processes, including pick-and-place equipment and infrared reflow soldering, making it suitable for high-volume manufacturing. The package is supplied on industry-standard 8mm tape wound onto 7-inch diameter reels.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The following parameters define the limits beyond which permanent damage to the device may occur. Operation under or at these conditions is not guaranteed and should be avoided for reliable performance.

• Power Dissipation (Pd): 182 mW. This is the maximum amount of power the device can dissipate as heat without exceeding its thermal limits.
• Peak Forward Current (IFP): 100 mA. This is the maximum allowable current under pulsed conditions (1/10 duty cycle, 1ms pulse width). It is higher than the DC rating due to reduced average heating.
• DC Forward Current (IF): 70 mA. This is the maximum continuous forward current recommended for reliable long-term operation.
• Reverse Voltage (VR): 5 V. Applying a reverse voltage exceeding this value can cause breakdown and damage the LED junction.
• Operating Temperature Range (Topr): -40°C to +85°C. The ambient temperature range within which the device is specified to operate correctly.
• Storage Temperature Range (Tstg): -40°C to +100°C. The temperature range for storing the device when not powered.

2.2 Electrical and Optical Characteristics

These parameters are measured at an ambient temperature (Ta) of 25°C and represent typical performance under specified test conditions.

• Luminous Intensity (Iv): Ranges from 1400 mcd (minimum) to 3550 mcd (typical maximum) at a forward current (IF) of 50 mA. This measures the perceived brightness of the light source in a specific direction (along the axis). The measurement uses a sensor filtered to match the human eye's photopic response (CIE curve).
• Viewing Angle (2θ1/2): 120 degrees (typical). This is the full angle at which the luminous intensity drops to half of its axial (on-axis) value. A wide viewing angle like 120° indicates a diffuse light output pattern, suitable for applications requiring wide-area illumination rather than a focused beam.
• Peak Emission Wavelength (λP): 591 nm (typical). This is the wavelength at which the spectral power distribution of the emitted light is at its maximum.
• Dominant Wavelength (λd): Ranges from 584.5 nm to 594.5 nm at IF=50mA. This is a colorimetric quantity derived from the CIE chromaticity diagram. It represents the single wavelength of a monochromatic light that would be perceived by the human eye as having the same color as the LED's light. It is the key parameter for defining the yellow color point.
• Spectral Line Half-Width (Δλ): 15 nm (typical). This is the width of the emission spectrum at half of its maximum power (Full Width at Half Maximum, FWHM). A value of 15nm indicates a relatively narrowband yellow emission, characteristic of AlInGaP technology.
• Forward Voltage (VF): 2.2 V (typical) at IF=50mA. This is the voltage drop across the LED when operating at the specified current. It is a critical parameter for designing the current-limiting circuitry.
• Reverse Current (IR): 10 μA (maximum) at VR=5V. This is the small leakage current that flows when the specified reverse voltage is applied.

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 requirements for color, brightness, and voltage.

3.1 Forward Voltage Binning

Binned at a test condition of IF = 50mA. Tolerance within each bin is +/-0.1V.

• D2: 1.80V (Min) - 2.00V (Max)
• D3: 2.00V (Min) - 2.20V (Max)
• D4: 2.20V (Min) - 2.40V (Max)
• D5: 2.40V (Min) - 2.60V (Max)

3.2 Luminous Intensity Binning

Binned at a test condition of IF = 50mA. Tolerance within each bin is +/-11%.

• W2: 1400 mcd (Min) - 1800 mcd (Max)
• X1: 1800 mcd (Min) - 2240 mcd (Max)
• X2: 2240 mcd (Min) - 2800 mcd (Max)
• Y1: 2800 mcd (Min) - 3550 mcd (Max)

3.3 Dominant Wavelength Binning

Binned at a test condition of IF = 50mA. Tolerance within each bin is +/-1nm. This directly controls the shade of yellow.

• H: 584.5 nm (Min) - 587.0 nm (Max)
• J: 587.0 nm (Min) - 589.5 nm (Max)
• K: 589.5 nm (Min) - 592.0 nm (Max)
• L: 592.0 nm (Min) - 594.5 nm (Max)

4. Performance Curve Analysis

While specific graphs are referenced in the datasheet (e.g., Figure 1 for spectral output, Figure 5 for viewing angle), the provided data allows for analysis of key relationships.

• Current vs. Luminous Intensity (I-Iv Curve): The luminous intensity is specified at 50mA. Typically, for AlInGaP LEDs, the light output increases sub-linearly with current. Operating above the recommended DC current may lead to increased heat, efficiency droop, and accelerated degradation.
• Temperature Dependence: The luminous intensity and forward voltage of LEDs are temperature-sensitive. Intensity generally decreases as junction temperature increases. The forward voltage typically has a negative temperature coefficient, decreasing by approximately 2 mV/°C for AlInGaP. Designs must account for thermal management to maintain stable optical performance.
• Spectral Distribution: With a typical peak at 591 nm and a half-width of 15 nm, the emission is centered in the yellow region of the visible spectrum. The dominant wavelength bins (H through L) ensure color consistency by grouping LEDs with very similar chromaticity coordinates.

5. Mechanical and Packaging Information

5.1 Device Package Dimensions

The LED conforms to an EIA standard SMD package outline. Detailed dimensional drawings are provided in the datasheet with all measurements in millimeters. Key features include the overall length, width, and height, as well as the placement and size of the solder pads and the lens structure. A tolerance of ±0.2 mm applies unless otherwise specified.

5.2 Polarity Identification

The datasheet includes a diagram indicating the cathode and anode terminals. Correct polarity must be observed during assembly. The cathode is typically marked by a notch, a green marking, or a shorter lead/tab on the package underside.

5.3 Tape and Reel Packaging

The device is supplied in embossed carrier tape with a protective cover tape.

• Tape Width: 8 mm.
• Reel Diameter: 7 inches (178 mm).
• Quantity per Reel: 2000 pieces.
• Minimum Order Quantity (MOQ) for Remainders: 500 pieces.
• The packaging follows ANSI/EIA-481 specifications to ensure compatibility with automated assembly equipment.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

The device is compatible with infrared (IR) reflow soldering processes. A recommended profile compliant with JEDEC J-STD-020B for lead-free soldering is provided.

• Pre-heat Temperature: 150°C to 200°C.
• Pre-heat Time: Maximum 120 seconds.
• Peak Body Temperature: Maximum 260°C.
• Time Above Liquidus (TAL): Recommended time is specified in the profile graph (typically 60-90 seconds).
• Maximum Number of Passes: Two times.

6.2 Hand Soldering

If hand soldering is necessary, extreme care must be taken.

• Iron Temperature: Maximum 300°C.
• Soldering Time per Pad: Maximum 3 seconds.
• Maximum Number of Times: One time only per joint.

6.3 Storage and Handling

• Sealed Package: Store at ≤30°C and ≤70% Relative Humidity (RH). Use within one year.
• Opened Package: Components exposed to ambient air should be stored at ≤30°C and ≤60% RH. It is recommended to complete IR reflow soldering within 168 hours (7 days) of opening the moisture barrier bag.
• Extended Storage (Opened): Store in a sealed container with desiccant or in a nitrogen desiccator.
• Baking: If components have been exposed for more than 168 hours, bake at approximately 60°C for at least 48 hours prior to soldering to remove absorbed moisture and prevent \"popcorning\" damage during reflow.

6.4 Cleaning

If post-assembly cleaning is required, use only approved solvents.

• Recommended Solvents: Ethyl alcohol or isopropyl alcohol.
• Procedure: Immerse at normal temperature for less than one minute. Do not use ultrasonic cleaning unless verified to be safe for the package.
• Warning: Do not use unspecified chemical liquids as they may damage the LED lens or package material.

7. Application Notes and Design Considerations

7.1 Drive Circuit Design

LEDs are current-driven devices. To ensure stable operation and longevity, a current-limiting mechanism is essential.

• Series Resistor (Circuit Model A): The most common and recommended method. A resistor (R) is placed in series with the LED. The value is calculated using Ohm's Law: R = (Vcc - VF) / IF, where Vcc is the supply voltage, VF is the LED forward voltage (use max value from bin for worst-case current calculation), and IF is the desired operating current (e.g., 20mA, 50mA). This method provides excellent current regulation per LED and is simple to implement.
• Parallel Connection Warning: Connecting multiple LEDs directly in parallel with a single current-limiting resistor (Circuit Model B) is not recommended. Small variations in the forward voltage (VF) between individual LEDs, even within the same bin, will cause significant imbalance in current sharing. One LED may draw most of the current, leading to overheating and premature failure, while others remain dim. Always use a separate series resistor for each LED or employ an active constant-current driver.

7.2 Thermal Management

Although power dissipation is relatively low, effective thermal design is crucial for maintaining performance and reliability.

• PCB Layout: Use adequate copper area (thermal pads or pours) connected to the LED's solder pads to act as a heat sink and conduct heat away from the device.
• Ambient Temperature: Ensure the operating ambient temperature is within the specified range. Consider the heat contributed by other components on the board.
• Current Derating: For operation at high ambient temperatures (approaching +85°C), consider derating (reducing) the operating current to lower the junction temperature and prevent accelerated lumen depreciation.

7.3 Typical Application Scenarios

The combination of a diffused lens, wide viewing angle, and yellow color makes this LED suitable for various applications:

• Status and Indicator Lights: Power on/off, standby mode, system activity, warning indicators in consumer electronics, industrial control panels, and instrumentation.
• Backlighting: Edge-lit or direct-lit backlighting for legends on membrane switches, keypads, and front panels where uniform, wide-angle illumination is desired.
• Automotive Interior Lighting: Warning lights, switch illumination, and general ambient lighting (subject to qualification for specific automotive standards).
• Signage and Decorative Lighting: Accent lighting in architectural features or decorative displays.

8. Technology Introduction and Trends

8.1 AlInGaP Technology

This LED is based on Aluminum Indium Gallium Phosphide (AlInGaP) semiconductor material. AlInGaP is particularly efficient in producing light in the red, orange, amber, and yellow regions of the spectrum. Key advantages include high luminous efficacy (lumens per watt) and good color purity (narrow spectral width) in these colors compared to older technologies like Gallium Phosphide (GaP). The material system allows for precise tuning of the bandgap, and thus the emitted wavelength, by adjusting the ratios of the constituent elements.

8.2 Diffused Lens vs. Clear Lens

The diffused (milky or frosted) lens material contains scattering particles. When light from the tiny semiconductor chip passes through this lens, it is scattered in many directions. This results in a much wider viewing angle (120° in this case) and a more uniform, softer appearance with reduced glare and no visible \"hot spot\" from the chip. This contrasts with a clear (water-clear) lens, which produces a more focused beam with a narrower viewing angle and a distinct, bright central point.

8.3 Industry Trends

The general trend in SMD LEDs is toward higher efficiency, higher reliability, and smaller package sizes. While this datasheet represents a mature and reliable product, newer developments in phosphor-converted yellow LEDs (using a blue chip with a yellow phosphor) can offer different trade-offs in efficacy, color rendering, and cost. Furthermore, advancements in packaging materials and thermal management techniques continue to push the limits of power density and lifetime for all LED technologies. The drive for miniaturization also leads to even smaller package footprints while maintaining or improving light output.