LTLMR4EW2DA LED Lamp Datasheet - Size 4.2x4.2x6.9mm - Voltage 1.8-2.4V - Power 120mW - Red 624nm - English Technical Document

1. Product Overview

The LTLMR4EW2DA is a high-brightness surface mount LED lamp designed for modern electronic assembly. It utilizes a red AllnGaP chip with a peak emission wavelength of 630nm, housed in a diffused package. Its primary design goal is to deliver intense, focused illumination suitable for applications requiring clear visibility without additional secondary optics.

The core advantages of this device include its high luminous intensity output, reaching up to 12000 mcd at a standard 20mA drive current, and its low power consumption. The package is engineered with advanced epoxy technology, providing superior moisture resistance and UV protection, enhancing its reliability for both indoor and outdoor use. It is fully compliant with lead-free, halogen-free, and RoHS environmental standards.

The target market encompasses a wide range of signage and display applications. Its narrow, controlled viewing angle of typically 25° makes it particularly suitable for video message signs, traffic signs, and various information display boards where directed light and high contrast are essential.

2. Technical Parameter Analysis

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the LED may occur. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd): 120 mW. This is the maximum amount of power the device can dissipate as heat at an ambient temperature (TA) of 25°C.
• DC Forward Current (IF): 50 mA. The maximum continuous forward current that can be applied.
• Peak Forward Current: 120 mA. This is permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10µs).
• Derating: The DC forward current must be linearly reduced by 0.75 mA for every degree Celsius above 45°C ambient temperature to prevent overheating.
• Operating Temperature Range: -40°C to +85°C. The ambient temperature range for reliable operation.
• Storage Temperature Range: -40°C to +100°C.
• Reflow Soldering Condition: Withstands a peak temperature of 260°C for a maximum of 10 seconds, compatible with standard lead-free reflow processes.

2.2 Electro-Optical Characteristics

These parameters are measured at TA=25°C and IF=20mA unless otherwise specified, representing typical performance.

• Luminous Intensity (Iv): Ranges from 7200 mcd (minimum) to 12000 mcd (maximum), with a typical value provided. A ±15% testing tolerance is applied to bin limits.
• Viewing Angle (2θ1/2): 25° typical, with a range of 20° to 30°. This is the full angle at which luminous intensity drops to half its axial value, defining the beam spread.
• Peak Emission Wavelength (λP): 630 nm typical. This is the wavelength at which the spectral power distribution is highest.
• Dominant Wavelength (λd): Between 618 nm and 630 nm. This is the single wavelength perceived by the human eye, defining the color as red.
• Spectral Line Half-Width (Δλ): 15 nm typical. This indicates the spectral purity or color saturation of the emitted light.
• Forward Voltage (VF): Between 1.8V and 2.4V at 20mA. This is the voltage drop across the LED when operating.
• Reverse Current (IR): 10 µA maximum at a reverse voltage (VR) of 5V. The device is not designed for reverse bias operation; this parameter is for leakage current testing only.

3. Binning System Specification

The LEDs are sorted into bins based on key performance parameters to ensure consistency within a production batch.

3.1 Luminous Intensity Binning

Bins are defined by minimum and maximum luminous intensity values at IF=20mA.

• Bin Code X: 7200 mcd (Min) to 9300 mcd (Max).
• Bin Code Y: 9300 mcd (Min) to 12000 mcd (Max).
• A tolerance of ±15% is applied to each bin limit during testing.

3.2 Forward Voltage Binning

Bins are defined by forward voltage ranges at IF=20mA.

• Bin Code 1A: 1.8V (Min) to 2.0V (Max).
• Bin Code 2A: 2.0V (Min) to 2.2V (Max).
• Bin Code 3A: 2.2V (Min) to 2.4V (Max).
• A tolerance of ±0.1V is applied to each bin limit.

4. Performance Curve Analysis

While specific graphical data is referenced in the datasheet, the typical relationships can be described:

• IV Curve (Current vs. Voltage): The forward voltage (VF) exhibits a logarithmic increase with forward current (IF). Operating at the recommended 20mA ensures optimal efficiency and longevity, avoiding the excessive heat generated at higher currents near the maximum rating.
• Temperature Dependence: Luminous intensity typically decreases as the junction temperature increases. The derating specification for forward current (0.75 mA/°C above 45°C) is a direct measure to manage this thermal effect and maintain performance.
• Spectral Distribution: The emission spectrum is centered around 630nm (peak) with a relatively narrow half-width of 15nm, characteristic of AllnGaP material, resulting in a saturated red color.

5. Mechanical and Package Information

5.1 Outline Dimensions

The LED features a surface-mount package with a round or oval lens. Key dimensions include:

• Package Body Size: 4.2mm ±0.2mm in length and width.
• Overall Height: 6.9mm ±0.5mm.
• Lead Spacing: 3.65mm ±0.2mm (measured where leads emerge from the package).
• A maximum resin protrusion of 1.0mm under the flange is specified.
• All dimensions include a default tolerance of ±0.25mm unless otherwise noted.

5.2 Polarity Identification

The device has three leads (P1, P2, P3). P1 and P3 are designated as the Anode (+), and P2 is designated as the Cathode (-). Correct polarity orientation during PCB layout and assembly is critical.

6. Soldering and Assembly Guidelines

6.1 Storage and Handling

This component is classified as Moisture Sensitivity Level (MSL) 3 per JEDEC J-STD-020.

• Unopened moisture barrier bags can be stored for up to 12 months at <30°C and 90% RH.
• After opening the bag, components must be stored at <30°C and 60% RH and must undergo soldering within 168 hours (7 days).
• Baking at 60°C ±5°C for 20 hours is required if the humidity indicator card shows >10% RH, floor life exceeds 168 hours, or exposure to >30°C/60% RH occurs. Baking should be performed only once.
• Use proper ESD (Electrostatic Discharge) precautions during handling.

6.2 Soldering Process

The LED is compatible with standard lead-free reflow soldering profiles.

• Reflow Profile: Peak temperature (Tp) should not exceed 260°C. The time above 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.
• Hand Soldering: If necessary, a soldering iron can be used at a maximum temperature of 315°C for no more than 3 seconds per lead, one time only.
• Cleaning: Isopropyl alcohol or similar alcohol-based solvents are recommended for post-soldering cleaning if required.

7. Packaging and Ordering Information

7.1 Packing Specification

The LEDs are supplied on embossed carrier tape for automated placement.

• Carrier Tape: Width is 16.0mm ±0.3mm. Pocket pitch is 8.0mm ±0.1mm.
• Reel: Each reel contains 1,000 pieces of LEDs.
• Humidity Protection: Each reel is packaged with a desiccant and a humidity indicator card inside a moisture barrier bag.
• Carton Packing: 3 reels (3,000 pcs) are packed per inner carton. 10 inner cartons (30,000 pcs total) are packed per outer shipping carton.

8. Application Recommendations

8.1 Typical Application Scenarios

• Video Message Signs: Ideal for pixelated displays due to high brightness and narrow beam angle.
• Traffic Signs & Signals: Suitable for supplementary lighting or status indicators requiring high visibility and reliability.
• Information Display Boards: Used in public transport information systems, retail advertising signs, and industrial status panels.

8.2 Design Considerations

• Current Limiting: Always use a series current-limiting resistor or a constant-current driver to maintain the forward current at or below the recommended 20mA for continuous operation.
• Thermal Management: Ensure adequate PCB copper area or thermal vias to dissipate heat, especially when operating at high ambient temperatures or near maximum ratings. Adhere to the current derating curve above 45°C.
• Optical Design: The 25° viewing angle provides directed light. For wider illumination, multiple LEDs or diffuser panels may be necessary.
• Polarity Checking: Verify PCB footprint matches the anode/cathode configuration (P1/P3 = Anode, P2 = Cathode) to prevent reverse connection.

9. Technical Comparison and Differentiation

Compared to standard SMD (e.g., 0603, 0805) or PLCC (Plastic Leaded Chip Carrier) package LEDs, the LTLMR4EW2DA offers distinct advantages for signage applications:

• Higher Luminous Intensity: Delivers significantly higher mcd output in a compact package, reducing the number of LEDs needed for a given brightness level.
• Integrated Beam Control: The molded lens provides a consistent 25° viewing angle without requiring additional secondary optics, simplifying mechanical design and reducing assembly cost.
• Enhanced Environmental Robustness: The advanced epoxy formulation offers better moisture and UV resistance compared to standard LED packages, improving longevity in outdoor or harsh environments.

10. Frequently Asked Questions (FAQ)

Q1: What is the difference between Peak Wavelength and Dominant Wavelength?
A1: Peak Wavelength (λP) is the physical wavelength where the LED emits the most optical power. Dominant Wavelength (λd) is a calculated value based on human eye sensitivity (CIE curve) that defines the perceived color. For this red LED, they are very close (630nm vs. 618-630nm).

Q2: Can I drive this LED with a 3.3V supply without a resistor?
A2: No. The forward voltage is only 1.8-2.4V. Connecting it directly to 3.3V would cause excessive current, exceeding the maximum rating and destroying the LED. A current-limiting resistor or regulator is mandatory.

Q3: What does MSL 3 mean for my production process?
A3: MSL 3 means the components are sensitive to moisture absorption. After removing them from the sealed bag, you have 168 hours (1 week) at factory floor conditions (<30°C/60% RH) to complete the reflow soldering process. If this time is exceeded, the components must be baked before use to prevent "popcorning" damage during soldering.

Q4: How is the viewing angle measured and specified?
A4: The viewing angle (2θ1/2) is the full angular width where the luminous intensity is at least half of the intensity measured directly on-axis (0°). A typical 25° angle means the light is concentrated within a relatively narrow cone, which is ideal for directed lighting applications.

11. Practical Design and Usage Case

Case: Designing a Compact Status Indicator Panel
An engineer is designing a control panel for industrial equipment that requires several high-visibility red status indicators. Space is limited, and the indicators need to be visible under bright ambient light. The LTLMR4EW2DA is selected because its high luminous intensity (up to 12000 mcd) ensures visibility. The narrow 25° viewing angle means light is not wasted illuminating areas outside the operator's direct line of sight. The surface-mount package allows for automated PCB assembly, reducing cost. The designer implements a simple circuit with a 5V supply, a current-limiting resistor calculated for ~18mA (providing a safety margin below 20mA), and follows the MSL3 handling guidelines to ensure assembly yield. The epoxy's moisture resistance ensures reliability in the potentially humid industrial environment.

12. Technical Principle Introduction

The LTLMR4EW2DA is based on an Aluminum Indium Gallium Phosphide (AllnGaP) semiconductor chip. When a forward voltage is applied across the p-n junction, electrons and holes recombine, releasing energy in the form of photons. The specific composition of the AllnGaP layers determines the bandgap energy, which directly corresponds to the wavelength of the emitted light—in this case, in the red spectrum (~624-630nm). The diffused lens encapsulant is doped with scattering particles to widen the light extraction from the chip and create a more uniform, less glaring appearance compared to a clear lens, while the package shape controls the final beam angle.

13. Industry Trends and Development

The trend in indicator and signage LEDs continues toward higher efficiency (more lumens or candela per watt), improved reliability, and smaller form factors. There is also a growing emphasis on precise optical control integrated directly into the package, as seen with this device's defined viewing angle, to simplify end-product design. Environmental regulations continue to drive the elimination of hazardous substances, making RoHS, lead-free, and halogen-free compliance standard. Furthermore, advancements in packaging materials aim to enhance resistance to thermal cycling, humidity, and UV exposure, extending product lifespans, especially for outdoor applications where this LED is targeted.