LTLMR4TG12DA LED Lamp Datasheet - Dimensions 4.2x4.2x6.9mm - Voltage 2.5-3.5V - Green 530nm - English Technical Documentation

1. Product Overview

The LTLMR4TG12DA is a high-brightness surface mount LED lamp designed for modern electronic assembly. It utilizes a diffused green package with a typical dominant wavelength of 530nm. The device is engineered for compatibility with standard SMT (Surface Mount Technology) assembly lines and industrial reflow soldering processes, making it suitable for high-volume manufacturing.

Its core design philosophy centers on providing a controlled, narrow radiation pattern directly from the package, eliminating the need for secondary optical lenses in many applications. This is achieved through a specific lens geometry that shapes the light output. The package is constructed using advanced epoxy materials that offer enhanced moisture resistance and UV protection, contributing to the device's reliability in demanding environments.

1.1 Key Features and Target Market

The primary advantages of this LED include its high luminous intensity output, which can reach up to 45,000 mcd under standard test conditions. This is coupled with low power consumption and high electrical-to-optical conversion efficiency. The device is fully compliant with environmental regulations, being lead-free, halogen-free, and RoHS compliant.

Its typical 25° viewing angle makes it particularly well-suited for applications requiring directed illumination or legibility from specific angles. The primary target markets for this component are professional signage and display systems. This includes video message signs, large-format traffic signs, and various forms of informational message boards where high brightness and good visibility are critical.

2. Technical Parameter Analysis

This section provides a detailed, objective breakdown of the device's key performance parameters as defined in its specification sheet.

2.1 Absolute Maximum Ratings

The device has defined limits that must not be exceeded to ensure reliable operation and prevent permanent damage. The maximum power dissipation is rated at 105 mW at an ambient temperature (TA) of 25°C. The maximum continuous forward current (IF) is 30 mA. For pulsed operation, a peak forward current of 100 mA is permissible under specific conditions: a duty cycle of ≤1/10 and a pulse width of ≤10µs. The device can operate within a temperature range of -40°C to +85°C and can be stored between -40°C and +100°C. A critical parameter for assembly is the reflow soldering condition, which is specified as a maximum of 260°C for 10 seconds.

2.2 Electrical and Optical Characteristics

Under standard test conditions (TA=25°C, IF=20mA), the device exhibits the following typical performance. The luminous intensity (Iv) has a wide range from a minimum of 21,000 mcd to a maximum of 45,000 mcd, with the specific value determined by the product's bin code (see Section 4). The forward voltage (VF) typically falls between 2.5V and 3.5V. The reverse current (IR) is very low, with a maximum of 10 µA when a reverse voltage (VR) of 5V is applied. It is important to note that the device is not designed for operation in reverse bias; this test is for characterization only.

The key optical parameters define its color and beam pattern. The dominant wavelength (λd) is specified between 527 nm and 535 nm, placing it firmly in the green region of the spectrum. The peak emission wavelength (λP) is typically around 520 nm. The spectral line half-width (Δλ) is approximately 30 nm, indicating the spectral purity of the emitted light. The viewing angle (2θ1/2), defined as the full angle at which luminous intensity drops to half of its on-axis value, is typically 25°, with a minimum of 20°.

3. Binning System Specification

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

3.1 Luminous Intensity Binning

The luminous intensity is classified into three primary bins when measured at IF=20mA:

• Bin Code 2: Minimum 21,000 mcd, Maximum 27,000 mcd.
• Bin Code 3: Minimum 27,000 mcd, Maximum 35,000 mcd.
• Bin Code 4: Minimum 35,000 mcd, Maximum 45,000 mcd.

A tolerance of ±15% is applied to the limits of each bin during testing and verification.

3.2 Dominant Wavelength Binning

The dominant wavelength, which perceptually defines the LED's color, is also binned:

• Bin Code G3: Minimum 527 nm, Maximum 531 nm.
• Bin Code G4: Minimum 531 nm, Maximum 535 nm.

The tolerance for each wavelength bin limit is ±1 nm, ensuring tight color control.

4. Performance Curve Analysis

While the specific graphical data is referenced in the datasheet, the typical curves for such a device would illustrate important relationships. The Current vs. Voltage (I-V) curve would show the exponential relationship characteristic of a diode, with the forward voltage increasing with current. The Luminous Intensity vs. Forward Current (I-L) curve is typically linear or slightly sub-linear in the operating range, showing how light output scales with drive current. The Luminous Intensity vs. Ambient Temperature curve is crucial for thermal management, as LED output generally decreases as junction temperature rises. Understanding these relationships is essential for designing stable and efficient driver circuits.

5. Mechanical and Package Information

5.1 Outline Dimensions and Polarity

The device has a compact surface-mount footprint. Key package dimensions are approximately 4.2 mm in length and width, with a total height of 6.9 mm. The leads have a spacing of 3.65 mm where they emerge from the package body. The polarity is clearly indicated: P1 and P3 are the anode connections, while P2 is the cathode. A critical mechanical note specifies that any protruded resin under the flange should not exceed 1.0 mm in height, which is important for ensuring proper seating on the PCB during assembly.

5.2 Package Design Considerations

The oval lens design is integral to achieving the specified 25° viewing angle without external optics. The diffused package material helps to homogenize the light output, reducing hotspots and providing a more uniform appearance, which is desirable in signage applications. The materials used provide a good balance of optical performance, mechanical strength, and environmental protection.

6. Soldering and Assembly Guidelines

Proper handling and assembly are critical to achieving the specified performance and reliability.

6.1 Moisture Sensitivity and Storage

This component is classified as Moisture Sensitivity Level 3 (MSL3) per JEDEC standard J-STD-020. LEDs in an unopened, factory-sealed moisture barrier bag (MBB) can be stored for up to 12 months at conditions not exceeding 30°C and 90% relative humidity (RH). After opening the MBB, the components must be kept in an environment of <30°C and <60% RH. The total "floor life"—the time from bag opening to completion of the high-temperature soldering process—must not exceed 168 hours (7 days). If these conditions are exceeded, or if the included humidity indicator card shows >10% RH, baking is required. The recommended bake condition is 60°C ±5°C for 20 hours, and this should be performed only once.

6.2 Soldering Parameters

Two soldering methods are addressed: Reflow Soldering: A lead-free reflow profile is recommended. The peak temperature (Tp) must not exceed 260°C, and the time above the liquidous temperature (TL=217°C) should be between 60 and 150 seconds. The time within 5°C of the peak temperature should be a maximum of 30 seconds. The device can withstand a maximum of two reflow cycles under these conditions. Hand Soldering (Iron): If manual soldering is necessary, the iron tip temperature should not exceed 315°C, and the contact time per lead should be limited to a maximum of 3 seconds. This should be performed only once.

6.3 Cleaning

If post-solder cleaning is required, only alcohol-based solvents such as isopropyl alcohol (IPA) should be used. Harsh or aggressive chemical cleaners should be avoided as they may damage the epoxy lens or package markings.

7. Packaging and Ordering Information

7.1 Carrier Tape and Reel Specifications

The components are supplied on embossed carrier tape for automated pick-and-place assembly. The tape width is 16.0 mm. Each reel contains 1,000 pieces of the LED. Detailed dimensions for the pocket and cover tape are provided to ensure compatibility with feeder systems.

7.2 Carton Packaging

The packaging is hierarchical for protection and logistics. One reel is packaged with a desiccant and a humidity indicator card inside a single Moisture Barrier Bag (MBB). Three such MBBs are then packed into one inner carton, totaling 3,000 pieces. Finally, ten inner cartons are packed into one master outer carton, resulting in a total of 30,000 pieces per outer carton.

8. Application Recommendations

8.1 Typical Application Scenarios

The primary application for this LED is in various forms of signage. Its high brightness and narrow viewing angle make it ideal for:

- Video Message Signs: Large outdoor or indoor displays where individual pixels require controlled directionality.

- Traffic Signs: Variable message signs on highways where high visibility and reliability are paramount.

- Informational Message Signs: Airport, train station, or public venue displays.

8.2 Design Considerations

Thermal Management: Although power dissipation is relatively low (105 mW max), proper PCB layout is essential. Ensure adequate copper area around the solder pads to act as a heat sink, especially if operating at or near the maximum current. The derating curve specifies a reduction of 0.5 mA per degree Celsius above 45°C ambient.

Current Driving: Always drive the LED with a constant current source, not a constant voltage. The recommended operating current is 20 mA. Exceeding the absolute maximum ratings, even briefly, can significantly reduce lifespan or cause immediate failure.

Optical Integration: The 25° viewing angle is inherent to the package. For applications requiring a different beam pattern, secondary optics (lenses or reflectors) will be necessary. The diffused lens helps in achieving color mixing when multiple LEDs are used in close proximity.

9. Technical Comparison and Differentiation

Compared to standard SMD LEDs (like 3528 or 5050 packages) or PLCC (Plastic Leaded Chip Carrier) LEDs, this device offers a key advantage: a built-in, controlled narrow viewing angle. Standard SMD LEDs often have wide viewing angles (120° or more), requiring additional external lenses to collimate the light for signage, which adds cost and complexity. This lamp integrates that function, potentially simplifying the final product design. Its high luminous intensity in a compact package also offers a better lumen-per-area density than many broader-angle alternatives when directional light is needed.

10. Frequently Asked Questions (FAQ)

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

A: Peak wavelength (λP) is the single wavelength at which the spectral power distribution is highest. Dominant wavelength (λd) is derived from the CIE chromaticity diagram and represents the perceived color of the light; it is the single wavelength that would match the color sensation. For monochromatic LEDs like this green one, they are often close but not identical.

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

A: While 30 mA is the absolute maximum DC forward current rating, it is not the recommended operating condition. Operating at the maximum rating will generate more heat, reduce efficiency, and potentially shorten the LED's lifespan. The standard test condition and typical application current is 20 mA.

Q: Why is the MSL3 rating and baking process important?

A: Moisture absorbed into the plastic package can vaporize rapidly during the high-temperature reflow soldering process, causing internal delamination, cracking, or "popcorning." This can lead to immediate failure or latent reliability issues. Following the MSL handling procedures prevents this damage.

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

A: You should specify both the luminous intensity bin (e.g., Bin 3) and the dominant wavelength bin (e.g., Bin G3) based on your application's requirements for brightness and color consistency. This ensures you receive LEDs with performance within a defined, narrow window.

11. Design and Usage Case Study

Consider a design for a mid-sized outdoor variable message sign for a parking garage. The sign needs to be clearly readable in daylight from a distance and at a specific approach angle. Using the LTLMR4TG12DA in Bin 4 for highest brightness and Bin G3 for consistent green color would be a suitable choice. The 25° viewing angle ensures light is directed towards drivers without excessive spillage, improving contrast. The designer would create a PCB array of these LEDs, driven by constant-current driver ICs. Careful thermal design on the metal-core PCB would manage heat, and the MSL3 handling procedures would be strictly followed during assembly to ensure long-term reliability in an outdoor environment with temperature fluctuations.

12. Operational Principle

The device operates on the principle of electroluminescence in a semiconductor material. When a forward voltage is applied across the anode and cathode, electrons and holes are injected into the active region of the semiconductor chip, which is composed of Indium Gallium Nitride (InGaN) for green emission. These charge carriers recombine, releasing energy in the form of photons (light). The specific composition of the InGaN layers determines the wavelength (color) of the emitted light—in this case, centered around 530 nm (green). The epoxy package encapsulates the chip, provides mechanical protection, and incorporates a lens to shape the light output into the desired 25° beam pattern.

13. Technology Trends

The general trend in LED technology for signage and professional lighting continues towards higher efficiency (more lumens per watt), improved color consistency and rendering, and greater reliability. Packaging technology is also evolving to allow for higher power density and better thermal management. For narrow-angle applications like signage, there is a focus on achieving precise beam control directly from the package with high optical efficiency, reducing the need for and losses associated with secondary optics. Environmental compliance and the use of sustainable materials in packaging are also increasingly important industry drivers.