LTLMR4TBTV3DA LED Lamp Datasheet - Dimensions 4.2x4.2x6.9mm - Voltage 2.5-3.5V - Blue 470nm - English Technical Documentation

1. Product Overview

This document details the specifications for a high-brightness, blue surface mount LED lamp. Designed for compatibility with standard Surface Mount Technology (SMT) assembly lines, this device is engineered for applications requiring reliable performance and controlled light distribution. The component features a specialized lens package that provides a narrow viewing angle, making it particularly suitable for sign board illumination where precise beam control is essential without the need for additional secondary optics. The construction utilizes advanced epoxy materials that offer enhanced moisture resistance and UV protection, contributing to the device's longevity and stability in various operating environments.

1.1 Core Advantages

• High Luminous Output: Delivers intense brightness suitable for high-visibility applications.
• Energy Efficiency: Operates with low power consumption while maintaining high luminous efficacy.
• Environmental Compliance: Manufactured as lead-free, halogen-free, and is fully compliant with RoHS directives.
• Robust Construction: Features superior moisture resistance, enhancing reliability.
• Optimized Optics: The integrated lens provides a typical 35-degree viewing angle for controlled light emission.

1.2 Target Applications

This LED is primarily targeted at signage and display applications where consistent, bright, and focused illumination is critical. Typical use cases include video message signs, traffic information signs, and various forms of indoor and outdoor message boards.

2. Technical Parameter Analysis

The following section provides a detailed, objective interpretation of the key electrical, optical, and thermal parameters specified for the device. Understanding these values is crucial for proper circuit design and thermal management.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation under or at these limits is not guaranteed.

• Power Dissipation (P_D): 85 mW. This is the maximum amount of power the device can dissipate as heat at an ambient temperature (T_A) of 25°C.
• Forward Current: A DC forward current (I_F) of 25 mA must not be exceeded for continuous operation. A higher peak forward current of 100 mA is permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10µs).
• Thermal Derating: For ambient temperatures above 45°C, the maximum allowable DC forward current must be reduced linearly at a rate of 0.62 mA per degree Celsius. This is critical for preventing thermal runaway.
• Temperature Ranges: The device is rated for operation from -40°C to +85°C and can be stored in environments from -40°C to +100°C.
• Reflow Soldering: The component can withstand a maximum reflow profile peak temperature of 260°C for up to 10 seconds, which aligns with common lead-free soldering processes.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at T_A=25°C and under specified test conditions.

• Luminous Intensity (I_V): Ranges from a minimum of 3200 mcd to a typical maximum of 7200 mcd when driven at I_F = 20 mA. A ±15% testing tolerance is applied to guaranteed values.
• Viewing Angle (2θ_1/2): Defined as the full angle where intensity drops to half its axial value. The typical value is 35°, with a range of 30° to 40° and a measurement tolerance of ±2°.
• Wavelength: The peak emission wavelength (λ_P) is typically 464 nm. The dominant wavelength (λ_d), which defines the perceived color, ranges from 460 nm to 480 nm. The spectral bandwidth (Δλ) is typically 25 nm.
• Forward Voltage (V_F): Between 2.5 V and 3.5 V at I_{F = 20 mA. Designers must account for this range when designing the driving circuitry.}
• Reverse Current (I_R): Maximum of 10 µA when a reverse voltage (V_R) of 5V is applied. It is important to note that the device is not designed for operation in reverse bias.

3. Binning System Specification

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

3.1 Luminous Intensity Binning

LEDs are classified into three bins (U, V, W) based on their minimum luminous intensity at 20 mA:
- Bin U: 3200 - 4200 mcd
- Bin V: 4200 - 5500 mcd
- Bin W: 5500 - 7200 mcd
A tolerance of ±15% applies to each bin limit.

3.2 Dominant Wavelength Binning

LEDs are also binned into five groups (B1 to B5) based on their dominant wavelength to control color variation:
- Bin B1: 460 - 464 nm
- Bin B2: 464 - 468 nm
- Bin B3: 468 - 472 nm
- Bin B4: 472 - 476 nm
- Bin B5: 476 - 480 nm
A tight tolerance of ±1 nm is maintained for each bin.

4. Mechanical & Package Information

4.1 Outline Dimensions

The device has a compact surface-mount footprint. Key dimensions include a body size of approximately 4.2 mm x 4.2 mm, with an overall height of 6.9 mm ±0.5 mm. The leads have a spacing where they emerge from the package, and a maximum resin protrusion under the flange of 1.0 mm is specified. All dimensions are in millimeters, with a standard tolerance of ±0.25 mm unless otherwise noted.

4.2 Polarity Identification & Pad Design

The component has three terminals: P1 (Anode), P2 (Cathode), and P3 (Anode). Correct polarity orientation is essential during PCB layout and assembly. A recommended solder pad pattern is provided to ensure reliable solder joint formation and proper thermal and electrical connection. The design includes rounded pad corners (R0.5) to mitigate solder wicking and stress concentration. It is explicitly stated that this LED is designed for reflow soldering onto a PCB and is not suitable for dip soldering processes.

5. Soldering & Assembly Guidelines

Proper handling and assembly are critical to maintaining device reliability and performance.

5.1 Moisture Sensitivity & Storage

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, the LEDs must be kept in an environment of <30°C and <60% RH, and all soldering must be completed within 168 hours (7 days). Baking at 60°C ±5°C for 20 hours is required if the humidity indicator card shows >10% RH, the floor life exceeds 168 hours, or the devices have been exposed to >30°C and 60% RH. Baking should be performed only once.

5.2 Reflow Soldering Profile

A lead-free reflow profile is recommended:
- Preheat/Soak: 150°C to 200°C for a maximum of 120 seconds.
- Time Above Liquidus (T_L=217°C): 60 to 150 seconds.
- Peak Temperature (T_P): 260°C maximum.
- Time within 5°C of Peak: 30 seconds maximum.
- Total Ramp Time: 25°C to peak temperature should not exceed 5 minutes.

5.3 Cleaning

If cleaning is necessary after soldering, only alcohol-based solvents such as isopropyl alcohol (IPA) should be used.

6. Packaging & Ordering Information

6.1 Packing Specification

The LEDs are supplied on embossed carrier tape for automated placement. The tape dimensions are specified to ensure compatibility with standard pick-and-place equipment. Each reel contains 1,000 pieces. For bulk shipping, the reels are further packaged: one reel is placed in a moisture barrier bag with a desiccant and humidity indicator card; three such bags are packed into an inner carton (3,000 pcs total); and ten inner cartons are packed into an outer shipping carton (30,000 pcs total).

7. Application Notes & Design Considerations

7.1 Typical Application Scenarios

This LED is well-suited for both indoor and outdoor signage applications, including video message signs, traffic signs, and general information displays. Its narrow viewing angle and high brightness make it effective for direct illumination of sign faces where light needs to be directed towards the viewer with minimal spill.

7.2 Design Considerations

• Current Driving: A constant current driver is recommended to maintain stable luminous output and color, as LED brightness is primarily a function of current, not voltage.
• Thermal Management: Although the device has good moisture resistance, proper PCB thermal design (adequate copper area for heat sinking) is necessary to manage the junction temperature, especially when operating near maximum ratings or in high ambient temperatures. Adhere to the derating curve above 45°C.
• ESD Protection: While not explicitly stated in the provided extract, standard ESD precautions should be observed during handling and assembly of all semiconductor devices.
• Optical Integration: The built-in lens provides a controlled beam. For applications requiring different beam patterns, secondary optics can be considered, though the native 35° angle is designed to be suitable for many direct-view sign applications.

8. Technical Comparison & Differentiation

Compared to standard SMD or PLCC (Plastic Leaded Chip Carrier) LED packages, this device offers a key advantage: its integrated oval/round lens package provides a controlled, narrow viewing angle (typically 35°) without requiring an additional external optical lens. This simplifies the mechanical design of the end product, reduces part count, and can lower overall system cost. The combination of high luminous intensity in a compact SMD footprint, coupled with robust moisture-resistant packaging, positions it favorably for demanding outdoor and semi-outdoor applications where reliability and optical performance are paramount.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (λ_P) is the single wavelength at which the emission spectrum is most intense (464 nm typical). Dominant wavelength (λ_d) is a calculated value derived from the color coordinates on the CIE diagram; it represents the single wavelength of pure monochromatic light that would match the perceived color of the LED (460-480 nm range). Dominant wavelength is more relevant for color specification.

Q: Why is there a derating factor for forward current above 45°C?
A: The derating factor (0.62 mA/°C) is necessary to limit the internal junction temperature of the LED. As ambient temperature rises, the device's ability to dissipate heat decreases. Reducing the operating current prevents excessive heat buildup that could accelerate degradation, reduce light output, or cause catastrophic failure.

Q: Can I use this LED for reverse-voltage indication or protection?
A: No. The datasheet explicitly states the device is not designed for reverse operation. The reverse current (I_R) parameter is for test purposes only. Applying a continuous reverse voltage will likely damage the LED.

Q: How critical is the 168-hour floor life after opening the moisture barrier bag?
A: It is very critical for reliability. MSL 3 components have absorbed moisture from the atmosphere. If they are subjected to reflow soldering after the 168-hour window without proper baking, the rapid heating can cause the trapped moisture to vaporize instantly, potentially leading to internal delamination or \"popcorning,\" which can crack the package and cause failure.

10. Operational Principles

This device is a Light Emitting Diode (LED) based on InGaN (Indium Gallium Nitride) semiconductor material grown on a substrate, which is responsible for its blue emission. When a forward voltage exceeding the device's threshold is applied, electrons and holes recombine in the active region of the semiconductor, releasing energy in the form of photons (light). The specific composition of the InGaN alloy determines the bandgap energy, which directly correlates to the wavelength (color) of the emitted light—in this case, around 470 nm (blue). The epoxy lens package serves to protect the semiconductor die, extract the light efficiently, and shape the emitted radiation into the desired viewing angle pattern.