LTLMH4TGVADA LED Lamp Datasheet - Dimensions 4.2x4.2x2.0mm - Voltage 2.5-3.5V - Green 525nm - English Technical Document

1. Product Overview

This document details the specifications for a high-brightness surface mount LED lamp. Designed for modern SMT assembly lines, this device offers superior optical performance in a compact, reliable package suitable for demanding applications.

1.1 Core Advantages and Target Market

The primary advantages of this LED include its high luminous intensity output, low power consumption, and high efficiency. It utilizes advanced epoxy technology providing excellent moisture resistance and UV protection. The package is lead-free, halogen-free, and RoHS compliant. Its typical narrow viewing angle of 100/40 degrees makes it particularly suitable for applications requiring controlled light distribution without additional secondary optics. The target markets include video message signs, traffic signs, and various other message signage applications where visibility and reliability are critical.

2. In-Depth Technical Parameter Analysis

A comprehensive analysis of the device's electrical, optical, and thermal characteristics is essential for proper integration into a design.

2.1 Absolute Maximum Ratings

The device must not be operated beyond these limits to prevent permanent damage. Key ratings include a maximum power dissipation of 105 mW, a DC forward current of 30 mA, and a peak forward current of 100 mA under pulsed conditions (duty cycle ≤1/10, pulse width ≤10ms). The operating temperature range is specified from -40°C to +85°C. The device can withstand reflow soldering at a peak temperature of 260°C for a maximum of 10 seconds.

2.2 Electrical and Optical Characteristics

Measured at a standard test condition of TA=25°C and IF=20mA, the key parameters define the device's performance. The luminous intensity (Iv) has a typical range, with minimum and maximum values defined in the bin table. The forward voltage (VF) ranges from 2.5V to 3.5V. The device emits green light with a peak wavelength (λP) typically at 522 nm and a dominant wavelength (λd) ranging from 519 nm to 539 nm, as defined by bin codes. The spectral half-width (Δλ) is typically 35 nm. The reverse current (IR) is a maximum of 10 μA at VR=5V, noting that the device is not designed for reverse operation.

2.3 Thermal Characteristics

Thermal management is crucial for LED longevity and performance stability. The maximum power dissipation is 105 mW at 25°C. The DC forward current must be derated linearly from 30 mA at 45°C down to 0 mA at 105°C, at a rate of 0.5 mA/°C. This derating curve is vital for designing systems that operate in elevated ambient temperatures.

3. Binning System Specification

To ensure color and brightness consistency in production, devices are sorted into bins based on key parameters.

3.1 Luminous Intensity Binning

Devices are classified into three primary bins for luminous intensity (Iv) measured at IF=20mA: Bin V (4200-5500 mcd), Bin W (5500-7200 mcd), and Bin X (7200-9300 mcd). A tolerance of ±15% is applied to each bin limit. The specific bin code is marked on the product packaging.

3.2 Dominant Wavelength Binning

For precise color control, dominant wavelength (λd) is binned into five categories: G1 (519-523 nm), G2 (523-527 nm), G3 (527-531 nm), G4 (531-535 nm), and G5 (535-539 nm). A tight tolerance of ±1 nm is maintained for each bin limit.

4. Performance Curve Analysis

While specific graphical curves are referenced in the document, typical performance trends can be described. The forward current vs. forward voltage (I-V) characteristic will show the exponential relationship common to diodes. The luminous intensity is typically a near-linear function of forward current within the recommended operating range. The forward voltage has a negative temperature coefficient, meaning it decreases as the junction temperature increases. The dominant wavelength may also shift slightly with changes in junction temperature and drive current.

5. Mechanical and Package Information

5.1 Outline Dimensions

The device features a compact surface-mount package. Key dimensions include a body size of approximately 4.2mm ±0.2mm in length and width, and a height of approximately 2.0mm ±0.5mm. The total package height including leads is approximately 6.2mm ±0.5mm. A detailed dimensioned drawing is provided in the source document, including notes on tolerances and lead spacing.

5.2 Polarity Identification and Pad Design

The device has three terminals: P1 (Anode), P2 (Cathode), and P3 (Anode). A recommended solder pad pattern is provided to ensure reliable soldering and effective thermal management. Note 2 for the pad pattern specifically recommends connecting the central pad (P3) to a heat sink or cooling mechanism to distribute heat during operation.

6. Soldering and Assembly Guidelines

6.1 Storage and Handling

The product is rated Moisture Sensitivity Level (MSL) 3 per JEDEC J-STD-020. In the sealed moisture barrier bag, it can be stored for 12 months at <30°C and <90% RH. After opening, the devices must be kept at <30°C and <60% RH and must be soldered within 168 hours (7 days). Baking at 60°C ±5°C for 20 hours is required if the humidity indicator card shows >10% RH, if floor life exceeds 168 hours, or if exposed to >30°C and >60% RH. Baking should be performed only once.

6.2 Soldering Process

Reflow Soldering: A lead-free reflow profile is recommended. The peak temperature must not exceed 260°C, and the time above 260°C must be a maximum of 10 seconds. Pre-heating should be in the range of 150-200°C for up to 120 seconds maximum. Reflow soldering must not be performed more than two times.
Hand Soldering: If necessary, a soldering iron can be used at a maximum temperature of 315°C for a maximum time of 3 seconds per joint. Hand soldering must not be performed more than one time.
Cleaning: Isopropyl alcohol or similar alcohol-based solvents are recommended for cleaning.
Important Notes: The device is designed for reflow soldering, not dip soldering. No external stress should be applied during soldering while the LED is at high temperature. Rapid cooling from peak temperature should be avoided.

7. Packaging and Ordering Information

7.1 Packing Specification

The devices are supplied on embossed carrier tape wound onto reels. The reel dimensions are standardized. Each reel contains a total of 1,000 pieces. The carrier tape dimensions are specified in detail in the source document, including pocket size, pitch, and cover tape specifications. The packaging is clearly marked as containing Electrostatic Sensitive Devices (ESD) requiring safe handling procedures.

8. Application Recommendations

8.1 Typical Application Scenarios

This LED is well-suited for both indoor and outdoor signage applications, as well as ordinary electronic equipment. Its high brightness and controlled viewing angle make it ideal for video message signs, traffic signs, and other informational displays where long-distance visibility or specific beam patterns are required.

8.2 Circuit Design Considerations

LEDs are current-operated devices. To ensure uniform brightness when connecting multiple LEDs in parallel, it is strongly recommended to use a current-limiting resistor in series with each individual LED. Driving multiple LEDs in parallel without individual resistors (as in Circuit B in the source document) can result in noticeable brightness differences due to variances in the forward voltage (Vf) characteristics of each device.

8.3 Electrostatic Discharge (ESD) Protection

The device is sensitive to electrostatic discharge and power surges, which can cause permanent damage. Proper ESD handling protocols must be followed during all stages of assembly, testing, and handling. This includes the use of grounded workstations, wrist straps, and conductive containers.

9. Technical Comparison and Differentiation

Compared to standard SMD or PLCC (Plastic Leaded Chip Carrier) packages, this surface mount lamp offers a significant advantage in optical control. Its integrated lens design provides a smooth radiation pattern and a narrow viewing angle (100/40° typical) without the need for an additional external optical lens. This simplifies the final product design, reduces part count, and can lower overall system cost while maintaining precise beam control. The advanced epoxy material also offers enhanced environmental robustness for outdoor applications.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (λP) is the wavelength at which the emission spectrum has its maximum intensity. Dominant wavelength (λd) is derived from the CIE chromaticity diagram and represents the single wavelength that best defines the perceived color of the light to the human eye. For specification and color consistency, the dominant wavelength is the more critical parameter.

Q: Why is a current-limiting resistor necessary for each LED in parallel?
A: The forward voltage (Vf) of LEDs has a manufacturing tolerance. If multiple LEDs are connected in parallel directly to a voltage source, the LED with the lowest Vf will draw disproportionately more current, leading to higher brightness and potentially overheating, while others remain dim. A series resistor for each LED helps balance the current and ensures uniform brightness.

Q: What does MSL 3 mean for my production process?
A: MSL 3 indicates the device can absorb damaging levels of moisture from the ambient air. Once the sealed bag is opened, you have 168 hours (7 days) to complete the soldering process under controlled humidity (<60% RH, <30°C). Exceeding this "floor life" requires baking the devices before soldering to drive out moisture and prevent "popcorning" or delamination during the high-temperature reflow process.

11. Design and Usage Case Study

Scenario: Designing a High-Visibility Outdoor Message Sign.
A designer is creating a solar-powered, weather-resistant traffic diversion sign. The key requirements are high brightness for daytime visibility, long lifetime, and reliability in varying temperatures. This LED is selected for its high luminous intensity (up to 9300 mcd) and robust package with moisture resistance. The narrow 100/40° viewing angle allows the sign's light to be directed effectively towards oncoming traffic, maximizing perceived brightness without wasteful light spill. The designer uses the bin table to specify LEDs from Bin X for maximum brightness and a specific G-bin (e.g., G3) for consistent green color across the sign. Each LED is driven via a constant-current driver circuit with individual series resistors to ensure uniformity. The recommended solder pad pattern is followed on the PCB, with the thermal pad (P3) connected to large copper pours for heat dissipation, ensuring the junction temperature remains within limits for long-term reliability.

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 of the semiconductor material (in this case, InGaN for green light), electrons recombine with holes within the device, releasing energy in the form of photons. The specific wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor material. The integrated lens of this SMD package is designed to shape and direct this emitted light into a specific radiation pattern.

13. Technology Trends

The general trend in LED technology continues towards higher efficiency (more lumens per watt), increased power density, and improved color rendering and consistency. Packaging technology is evolving to better manage the heat generated at higher drive currents, often through improved thermal paths within the package itself, such as the exposed thermal pad featured in this device. There is also a focus on miniaturization while maintaining or increasing optical output, and on enhancing reliability for harsh environment applications like automotive and outdoor signage. The drive for sustainability pushes for further elimination of hazardous materials and improvements in manufacturing efficiency.