SMD LED LTST-416GEBW-P3 Datasheet - White Diffused Lens - RGB Chip - 5mA Drive - English Technical Document

1. Product Overview

This document details the specifications for a surface-mount device (SMD) LED designed for automated printed circuit board assembly. The component features a white diffused lens and integrates three distinct semiconductor light sources within a single package: a green InGaN chip, a red AlInGaP chip, and a blue InGaN chip. The combined output through the diffused lens creates a white light appearance. This design is targeted at space-constrained applications across consumer electronics, telecommunications, and industrial equipment where reliable status indication, symbol illumination, or front-panel backlighting is required.

1.1 Key Features

• Compliant with RoHS environmental directives.
• Packaged on 12mm tape within 7-inch diameter reels for automated pick-and-place systems.
• Standardized EIA package footprint for design compatibility.
• Logic-level compatible drive current.
• Withstands infrared reflow soldering processes.
• Preconditioned to JEDEC Moisture Sensitivity Level 3.

1.2 Target Applications

• Status indicators in telecommunications and networking hardware.
• Signal and symbol illumination in office automation and home appliances.
• Front panel backlighting for industrial control equipment.
• General purpose indicator lighting in consumer electronics.

2. Technical Parameters: In-Depth Objective Analysis

The following section provides a detailed, objective breakdown of the device's electrical, optical, and thermal characteristics as defined in the source material. All data is referenced to an ambient temperature (Ta) of 25°C unless otherwise specified.

2.1 Absolute Maximum Ratings

These values represent stress limits beyond which permanent damage to the device may occur. Continuous operation at these limits is not advised.

• Power Dissipation (Pd): 90 mW for Green/Blue chips; 69 mW for Red chip. This parameter is crucial for thermal management design.
• Peak Forward Current (I_F(PEAK)): 100 mA for all chips, under pulsed conditions (1/10 duty cycle, 0.1ms pulse width).
• Continuous Forward Current (I_F): 30 mA DC for all chips.
• Operating Temperature Range: -40°C to +85°C.
• Storage Temperature Range: -40°C to +100°C.

2.2 Electro-Optical Characteristics

Measured at a standard test current of I_F = 5mA for each chip. These are the typical performance parameters under normal operating conditions.

• Luminous Intensity (I_v):
  • Green: 600 - 1200 mcd (millicandela)
  • Red: 200 - 400 mcd
  • Blue: 100 - 200 mcd
• Viewing Angle (2θ_1/2): Typically 120 degrees. This wide angle is a result of the diffused lens, providing a more uniform light distribution compared to clear-lens LEDs.
• Dominant Wavelength (λ_d):
  • Green: 523 - 535 nm
  • Red: 617 - 630 nm
  • Blue: 465 - 477 nm
• Forward Voltage (V_F):
  • Green: 2.0 - 3.0 V
  • Red: 1.4 - 2.3 V
  • Blue: 2.0 - 3.0 V
• Reverse Current (I_R): Maximum 10 μA at V_R = 5V. The device is not designed for reverse-bias operation; this parameter is for test purposes only.

3. Binning System Explanation

To ensure color and brightness consistency in production, devices are sorted into bins. The white light output is a function of the combined RGB chips, measured with all three driven at 5mA.

3.1 Luminous Intensity (I_v) Rank

Devices are categorized based on their total luminous intensity output. T1 Bin: 900 - 1300 mcd (approx. 2.7 - 3.9 lumens) T2 Bin: 1300 - 1800 mcd (approx. 3.9 - 5.4 lumens) Tolerance per bin is ±11%.

3.2 Chromaticity (CIE) Rank

Devices are binned according to their color coordinates on the CIE 1931 chromaticity diagram, which defines the perceived color of the white light. The bin codes (e.g., H4, J5, K6, L4) represent specific quadrilateral regions on the x,y coordinate plane. Each bin has four defined corner points (Point1-4) for x and y coordinates. The tolerance for placement within a selected hue bin is ±0.01 in both x and y coordinates. This precise binning allows designers to select LEDs with very tight color consistency for their applications.

4. Mechanical and Packaging Information

4.1 Package Dimensions and Pin Assignment

The device conforms to a standard SMD footprint. Critical dimensions include body size and pad spacing. All dimensional tolerances are ±0.2 mm unless otherwise noted. The pin assignment for activating individual colors is as follows: The anode (common positive) is connected to pin 1. The green cathode is pin 2, the red cathode is pins 3 & 4 (internally connected), and the blue cathode is pin 6. Pins 5 and others may be no-connect (NC) or mechanical anchors.

4.2 Recommended PCB Land Pattern

A top-view drawing of the suggested solder pad layout is provided to ensure proper soldering and mechanical stability. Adhering to this pattern helps prevent tombstoning (one end lifting during reflow) and ensures good solder fillets.

4.3 Tape and Reel Packaging

The components are supplied in embossed carrier tape with a protective cover tape. Key packaging specifications include:

• Carrier Tape Width: 12 mm.
• Reel Diameter: 7 inches (178 mm).
• Quantity per Full Reel: 2000 pieces.
• Minimum Order Quantity for Partial Reels: 500 pieces.
• Maximum consecutive missing components (pockets): 2.
• Packaging conforms to EIA-481-1-B standards.

5. Soldering and Assembly Guidelines

5.1 IR Reflow Soldering Profile (Pb-Free Process)

The recommended profile follows J-STD-020B for lead-free soldering.

• Pre-heat: 150°C to 200°C.
• Pre-heat Time: Maximum 120 seconds.
• Peak Body Temperature: Maximum 260°C.
• Time Above Liquidus: Recommended 10 seconds maximum.
• Number of Reflow Cycles: Maximum two times.

A graphical temperature vs. time profile is typically provided to visualize the ramp-up, soak, reflow, and cooling stages.

5.2 Hand Soldering

If manual soldering is necessary:

• Iron Temperature: Maximum 300°C.
• Contact Time: Maximum 3 seconds per joint.
• Important: Hand soldering should be performed only once to avoid thermal stress.

5.3 Cleaning

Post-solder cleaning must be performed with care. Only specified solvents should be used. Recommended agents are ethyl alcohol or isopropyl alcohol at room temperature. The LED should be immersed for less than one minute. Unspecified chemicals may damage the epoxy lens or package.

6. Storage and Handling Cautions

6.1 Storage Conditions

Sealed Moisture-Barrier Bag (MBP): Store at ≤30°C and ≤70% Relative Humidity (RH). The shelf life within the sealed bag with desiccant is one year. After Bag Opening: The "floor life" begins. Store at ≤30°C and ≤60% RH. It is strongly recommended to complete the IR reflow process within 168 hours (7 days) of exposure. For storage beyond this period, components should be placed in a sealed container with fresh desiccant or in a nitrogen desiccator. Components exposed for more than 168 hours require a baking procedure (approximately 60°C for at least 48 hours) prior to soldering to remove absorbed moisture and prevent "popcorning" (package cracking due to vapor pressure during reflow).

6.2 Application Notes and Limitations

This LED is intended for use in standard commercial and industrial electronic equipment. It is not designed or qualified for applications where failure could lead to direct risk to life, health, or safety—such as in aviation, medical life-support, or critical transportation control systems. For such high-reliability applications, consultation with the component manufacturer for specific qualification data is mandatory.

7. Design Considerations and Application Suggestions

7.1 Current Limiting

Due to the different forward voltages (V_F) of the red, green, and blue chips, driving them from a common voltage source requires separate current-limiting resistors for each color channel. The resistor value is calculated using Ohm's Law: R = (V_supply - V_F) / I_F. Using the typical V_F and the desired drive current (e.g., 5mA for spec compliance, up to 30mA max) will yield the appropriate resistance and power rating.

7.2 Thermal Management

While the power dissipation is relatively low, proper PCB design is essential for longevity. Ensure the recommended solder pads are used to provide adequate thermal conduction away from the LED junction. For applications driving the LED at or near its maximum continuous current (30mA), attention to ambient temperature and board layout is important to stay within the specified operating temperature range.

7.3 Optical Integration

The white diffused lens provides a wide, uniform viewing angle (120°), making it suitable for applications where the LED may be viewed from off-axis angles. The diffused nature reduces hotspots and glare. For applications requiring a more directed beam, external secondary optics (lenses, light pipes) would be necessary.

8. Typical Performance Curves Analysis

The datasheet includes graphical representations of key relationships, which are vital for understanding device behavior under non-standard conditions.

• Relative Luminous Intensity vs. Forward Current: This curve shows how light output increases with drive current, typically in a sub-linear fashion, highlighting efficiency changes.
• Forward Voltage vs. Forward Current: Demonstrates the diode's exponential I-V characteristic.
• Relative Luminous Intensity vs. Ambient Temperature: Shows the derating of light output as junction temperature increases. This is critical for high-temperature environment designs.
• Spectral Distribution: While not always detailed for white LEDs, understanding the peak wavelengths and spectral half-widths (Δλ: ~30nm G, ~20nm R, ~25nm B) of the individual chips informs color rendering and filter selection.

These curves allow designers to extrapolate performance for operating points other than the standard test condition of 5mA at 25°C.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive all three colors simultaneously to get brighter white light? A: Yes, but you must ensure the total power dissipation does not exceed the lowest maximum rating among the active chips (69mW for the red chip, in this case) and that the junction temperature remains within limits. The current for each channel must be controlled independently.

Q: Why is the forward voltage different for each color? A: The forward voltage is a fundamental property of the semiconductor material's bandgap. Red AlInGaP LEDs have a lower bandgap than green and blue InGaN LEDs, resulting in a lower V_F.

Q: What does "preconditioning to JEDEC Level 3" mean? A: It means the components have been classified as Moisture Sensitivity Level 3 (MSL 3). This indicates the maximum allowable floor life after the moisture barrier bag is opened is 168 hours at ≤30°C/60% RH before they require baking for reflow.

Q: How do I select the correct bin for my application? A: For applications where color consistency is critical (e.g., multi-LED status bars or backlights), specify a single, tight CIE bin code (e.g., J5) and a single luminous intensity bin (e.g., T1). For less critical applications, a wider bin selection may be acceptable and potentially more cost-effective.

10. Operational Principle and Technology Context

This LED operates on the principle of electroluminescence in semiconductor materials. When a forward voltage is applied across the p-n junction of each chip, electrons and holes recombine, releasing energy in the form of photons. The wavelength (color) of the light is determined by the bandgap energy of the specific semiconductor material: AlInGaP for red, and InGaN for green and blue. The "white" light is not produced by a single white phosphor (as in a phosphor-converted white LED) but is an additive color mixture of the three primary colored lights (Red, Green, Blue) as they pass through the diffused white encapsulant. This RGB method allows for potential color tuning by varying the current to each chip, though this datasheet specifies operation for a fixed white point.

The SMD package format represents the industry standard for high-volume, automated assembly. The use of a diffused lens epoxy incorporates scattering particles to widen the viewing angle and soften the light output, making it ideal for indicator purposes where direct viewing is common. The integration of three chips in one package saves PCB space compared to using three discrete single-color LEDs.