LTL5H3TBDS Blue LED Datasheet - Through Hole Lamp - 110x45 Degree Viewing Angle - 3.0-4.0V Forward Voltage - 35mA Max Current - English Technical Document

1. Product Overview

This document provides the complete technical specifications for a high-efficiency, blue diffused LED lamp designed for through-hole mounting. The device utilizes InGaN (Indium Gallium Nitride) technology to produce blue light. It is characterized by a wide viewing angle, making it suitable for applications requiring broad illumination or status indication. The primary advantages of this component include high luminous intensity output relative to its power consumption, compatibility with integrated circuits due to low current requirements, and versatile mounting options on printed circuit boards or panels.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The device's operational limits are defined at an ambient temperature (T_A) of 25°C. Exceeding these ratings may cause permanent damage.

• Power Dissipation: 125 mW maximum.
• DC Forward Current (I_F): 35 mA continuous.
• Peak Forward Current: 100 mA, permissible under pulsed conditions (1/10 duty cycle, 10ms pulse width).
• Derating: The maximum forward current must be linearly derated by 0.6 mA for every degree Celsius above 25°C.
• Operating Temperature Range: -30°C to +85°C.
• Storage Temperature Range: -40°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm (0.0787\") from the LED body.

2.2 Electrical and Optical Characteristics

Key performance parameters are measured at T_A=25°C and a standard test current (I_F) of 20mA, unless otherwise specified.

• Luminous Intensity (I_V): Ranges from a minimum of 430 mcd to a maximum of 1210 mcd, with a typical value of 700 mcd. Measurement follows the CIE eye-response curve, and a ±15% testing tolerance is applied to guaranteed values.
• Viewing Angle (2θ_1/2): Asymmetric at 110° (major axis) / 45° (minor axis). This is the off-axis angle where intensity drops to half its axial value.
• Peak Emission Wavelength (λ_P): Typically 473 nm.
• Dominant Wavelength (λ_d): Ranges from 465 nm to 475 nm, defining the perceived color.
• Spectral Line Half-Width (Δλ): Approximately 20 nm, indicating the spectral purity.
• Forward Voltage (V_F): Between 3.0V and 4.0V at 20mA.
• Reverse Current (I_R): Maximum of 100 µA at a reverse voltage (V_R) of 5V.

3. Binning System Specification

The LEDs are sorted into bins based on key optical parameters to ensure consistency within an application.

3.1 Luminous Intensity Binning

Bins are defined by minimum and maximum luminous intensity values at I_F=20mA, with a ±15% tolerance on bin limits.

• Bin Code NS: 430 mcd (Min) to 600 mcd (Max)
• Bin Code NT: 600 mcd to 860 mcd
• Bin Code NU: 860 mcd to 1210 mcd

The specific bin code is marked on each packing bag.

3.2 Dominant Wavelength Binning

LEDs are also binned by dominant wavelength with a ±1nm tolerance.

• Bin Code B08: 465 nm to 470 nm
• Bin Code B09: 470 nm to 475 nm

4. Performance Curve Analysis

The datasheet references typical characteristic curves which illustrate the relationship between key parameters. While specific graphs are not detailed in the provided text, standard LED curves typically include:

• Forward Current vs. Forward Voltage (I-V Curve): Shows the exponential relationship, critical for designing current-limiting circuits.
• Luminous Intensity vs. Forward Current: Demonstrates how light output increases with current, up to the maximum rating.
• Luminous Intensity vs. Ambient Temperature: Shows the decrease in output as junction temperature rises, highlighting the importance of thermal management.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing the peak at ~473 nm and the ~20 nm half-width.
• Viewing Angle Pattern: A polar plot depicting the asymmetric 110°/45° intensity distribution.

5. Mechanical and Package Information

5.1 Package Dimensions and Notes

The LED is a through-hole package with a diffused lens. Key dimensional notes include:

• All dimensions are in millimeters (inches provided in parentheses).
• A standard tolerance of ±0.25mm (.010\") applies unless specified otherwise.
• The maximum protrusion of resin under the component flange is 1.0mm (.04\").
• Lead spacing is measured at the point where the leads emerge from the package body.
• During lead forming, bending must occur at least 3mm from the base of the LED lens to avoid stress on the epoxy body and internal die connections.

6. Soldering and Assembly Guidelines

6.1 Soldering Process

Proper soldering is crucial to prevent damage. A minimum clearance of 3mm must be maintained between the solder point and the base of the lens.

• Hand Soldering (Iron): Maximum temperature 300°C, for a maximum of 3 seconds per lead. This should be performed only once.
• Wave Soldering: Pre-heat to a maximum of 100°C for up to 60 seconds. The solder wave temperature should not exceed 260°C, with contact time limited to 5 seconds maximum.
• Important: Infrared (IR) reflow soldering is NOT suitable for this through-hole LED product. Excessive heat or time can deform the lens or cause catastrophic failure.

6.2 Storage and Handling

• Storage: Recommended ambient not exceeding 30°C and 70% relative humidity. LEDs removed from original packaging should be used within three months. For longer storage, use a sealed container with desiccant or a nitrogen ambient.
• Cleaning: Use alcohol-based solvents like isopropyl alcohol if necessary.
• ESD Protection: LEDs are sensitive to electrostatic discharge. Use grounded wrist straps, anti-static gloves, grounded workstations, and ionizers to neutralize static charge on the lens.

7. Packaging and Ordering Information

The standard packaging specification is as follows:

• 500 pieces per anti-static packing bag.
• 10 packing bags per inner carton (5,000 pieces total).
• 8 inner cartons per outer shipping carton (40,000 pieces total).
• Within a shipping lot, only the final pack may contain a non-full quantity.

The primary part number for this device is LTL5H3TBDS.

8. Application Recommendations and Design Considerations

8.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness when using multiple LEDs, especially in parallel configurations, a series current-limiting resistor is mandatory for each LED. The circuit diagram labeled \"Circuit A\" in the datasheet is the recommended configuration. Driving LEDs in parallel without individual resistors (\"Circuit B\") is discouraged, as small variations in the forward voltage (V_F) characteristic between individual LEDs can lead to significant differences in current share and, consequently, perceived brightness.

The resistor value (R) can be calculated using Ohm's Law: R = (V_Supply - V_F) / I_F, where V_F should be chosen conservatively (e.g., the maximum value of 4.0V) to ensure the current does not exceed the desired level across all units.

8.2 Thermal Management

While the power dissipation is relatively low (125 mW max), the derating specification of 0.6 mA/°C above 25°C is critical for reliability. In high ambient temperature environments or applications with high duty cycles, the maximum continuous current must be reduced accordingly. Adequate spacing on the PCB and avoiding enclosed spaces can help dissipate heat.

8.3 Typical Application Scenarios

This LED is intended for ordinary electronic equipment, including:

• Status and power indicators on consumer electronics, appliances, and industrial control panels.
• Backlighting for switches, legends, or small panels.
• Decorative lighting in toys or novelty items.
• General purpose signaling and illumination where a wide viewing angle is beneficial.

Important Note: The datasheet explicitly states that consultation is required before using this LED in applications where failure could jeopardize life or health, such as aviation, medical, transportation, or safety-critical systems.

9. Technical Comparison and Differentiation

The key differentiating features of this LED are its specific combination of attributes:

• Wide, Asymmetric Viewing Angle (110°/45°): Unlike many LEDs with a circular viewing pattern, this asymmetric pattern is ideal for applications requiring a broad horizontal spread with a more constrained vertical spread, such as panel indicators viewed from the front.
• Diffused Lens: The diffused lens material softens the light output, reducing glare and creating a more uniform appearance, which is preferable for status indicators viewed directly.
• Through-Hole Reliability: Offers robust mechanical attachment and historically proven solder joint reliability compared to some surface-mount alternatives, which can be advantageous in applications subject to vibration or requiring manual assembly.
• InGaN Technology: Provides efficient blue light generation with the specified wavelength and intensity characteristics.

10. Frequently Asked Questions (FAQ)

10.1 Can I drive this LED directly from a 5V logic output?

No. The forward voltage ranges from 3.0V to 4.0V. Connecting it directly to a 5V source without a current-limiting resistor would force excessive current through the LED, exceeding its absolute maximum rating and causing immediate or rapid failure. A series resistor is always required.

10.2 Why is the viewing angle asymmetric?

The asymmetric viewing angle (110° major, 45° minor) is a result of the LED chip's construction and the shape of the diffused lens package. It is a designed characteristic to tailor the light emission pattern for specific applications, like front-panel indicators where wide side-to-side visibility is more important than top-to-bottom visibility.

10.3 What is the difference between Peak Wavelength and Dominant Wavelength?

Peak Wavelength (λ_P): The single wavelength at which the spectral output is maximum (e.g., 473 nm). Dominant Wavelength (λ_d): A calculated value derived from the CIE chromaticity diagram that represents the single wavelength of a pure monochromatic light that would appear to have the same color as the LED's actual output. It is the parameter that best defines the perceived color (e.g., 465-475 nm).

10.4 How do I select the correct bin for my application?

Select the luminous intensity bin (NS, NT, NU) based on the minimum brightness required for your application under worst-case conditions (e.g., maximum temperature, minimum V_F). For color-critical applications, specify the dominant wavelength bin (B08, B09) to ensure consistency across all units in your product. Consult the manufacturer or distributor for availability of specific bin combinations.

11. Practical Design Case Study

Scenario: Designing a cluster of three blue LED status indicators for a front panel, powered by a 5V rail. Uniform brightness is essential.

1. Circuit Design: Use the recommended \"Circuit A\" configuration: each LED gets its own series resistor connected to the 5V supply.
2. Current Selection: Choose a drive current. 20mA is standard, but 15mA could be used for lower power/longer life if the intensity (check the binning table at lower current) is sufficient.
3. Resistor Calculation: Using worst-case V_F (min) for current limit: R = (5V - 3.0V) / 0.020A = 100Ω. Using typical V_F for expected brightness: R = (5V - 3.5V) / 0.020A = 75Ω. A standard 82Ω resistor is a good compromise, yielding I_F ~18-24mA depending on the actual V_F of each LED.
4. Binning: Specify Bin NT or NU for higher, more consistent brightness. Specify Bin B08 or B09 based on the desired blue hue.
5. Layout: Place LEDs on the PCB with at least 3mm of straight lead before any bend. Ensure the soldering point on the PCB is >3mm from the LED body.
6. Assembly: Form leads first, then insert into PCB. Use wave soldering with the specified profile or careful hand soldering.

12. Operating Principle Introduction

This LED is a semiconductor photonic device. Its core is a chip made of InGaN materials forming a p-n junction. When a forward voltage exceeding the junction's threshold is applied, electrons and holes are injected across the junction. When these charge carriers recombine, energy is released in the form of photons (light). The specific composition of the InGaN alloy determines the bandgap energy, which directly dictates the wavelength (color) of the emitted light, in this case, blue. The diffused epoxy lens surrounding the chip serves to protect it, shape the beam into the specified viewing pattern, and diffuse the light to reduce glare.

13. Technology Trends and Context

While surface-mount device (SMD) LEDs dominate modern high-volume electronics due to their smaller size and suitability for automated assembly, through-hole LEDs like this one remain relevant. Their key advantages are mechanical robustness, ease of manual prototyping and repair, and superior heat dissipation via longer leads in some cases. The InGaN technology used is mature and highly efficient for blue emission. Current trends in general LED technology focus on increasing efficiency (lumens per watt), improving color rendering index (CRI) for white LEDs, and developing miniaturized and high-power packages. For indicator-type LEDs, the trend is towards lower operating currents while maintaining sufficient brightness to save energy in battery-powered devices.