LTL1KH6FK Amber LED Lamp Datasheet - 5mm Diameter - 2.4V Forward Voltage - 75mW Power Dissipation - English Technical Document

1. Product Overview

This document details the specifications for a 5mm through-hole LED lamp. This component is designed for status indication and signaling applications across a broad range of electronic equipment. It is offered in an amber color, achieved using AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology combined with a water-clear lens, which enhances light output and viewing angle.

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 is a lead-free product compliant with the RoHS directive, making it suitable for global markets with strict environmental regulations. Its versatile package allows for easy mounting on printed circuit boards (PCBs) or panels. The target applications span multiple industries, including communication equipment, computers, consumer electronics, home appliances, and industrial controls, where reliable and bright status indication is required.

2. In-Depth Technical Parameter Analysis

Understanding the electrical and optical parameters is crucial for reliable circuit design and achieving consistent performance.

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 (Pd): 75 mW at an ambient temperature (TA) of 25°C. This is the maximum power the LED package can dissipate as heat.
• DC Forward Current (IF): 30 mA continuous.
• Peak Forward Current: 60 mA, permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10 μs).
• Derating: The maximum DC forward current must be linearly reduced by 0.45 mA for every degree Celsius the ambient temperature rises above 30°C.
• Operating Temperature Range: -40°C to +85°C.
• Storage Temperature Range: -40°C to +100°C.
• Lead Soldering Temperature: 260°C maximum for 5 seconds, measured at a point 2.0mm (0.079 inches) from the LED body.

2.2 Electrical & Optical Characteristics

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

• Luminous Intensity (Iv): Ranges from 240 mcd (minimum) to 880 mcd (maximum), with a typical value provided. This parameter is binned (see Section 4). The measurement uses a sensor/filter approximating the CIE photopic eye-response curve. A ±15% testing tolerance is included in the guarantee.
• Viewing Angle (2θ1/2): 75 degrees. This is the full angle at which the luminous intensity drops to half of its axial (on-center) value.
• Peak Emission Wavelength (λp): 611 nm. This is the wavelength at the highest point of the emitted light spectrum.
• Dominant Wavelength (λd): Ranges from 600 nm to 610 nm. This is derived from the CIE chromaticity diagram and represents the perceived color of the LED. This parameter is also binned.
• Spectral Line Half-Width (Δλ): 17 nm. This indicates the spectral purity; a smaller value means a more monochromatic light.
• Forward Voltage (VF): 2.4V typical at 20mA. The minimum is listed as 2.05V.
• Reverse Current (IR): 100 μA maximum when a reverse voltage (VR) of 5V is applied. Important: This device is not designed for operation under reverse bias; this test condition is for characterization only.

3. Binning System Specification

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

3.1 Luminous Intensity Binning

The Iv is classified into five bin codes (J0, K0, L0, M0, N0), each with a defined minimum and maximum intensity range at IF=20mA. The tolerance for each bin limit is ±15%.

3.2 Dominant Wavelength Binning

The λd is classified into three bin codes (H23, H24, H25), covering the range from 600.0 nm to 610.0 nm. The tolerance for each bin limit is ±1 nm. The specific bin code for intensity and wavelength is marked on each packing bag, allowing for selective matching in applications requiring uniformity.

4. Performance Curve Analysis

The datasheet references typical characteristic curves which are essential for understanding device behavior under varying conditions. While the specific graphs are not reproduced in text, they typically include:

• Relative Luminous Intensity vs. Forward Current: Shows how light output increases with current, typically in a non-linear fashion, highlighting the importance of current regulation.
• Forward Voltage vs. Forward Current: Illustrates the diode's I-V characteristic, crucial for calculating series resistor values.
• Relative Luminous Intensity vs. Ambient Temperature: Demonstrates the negative temperature coefficient of light output, where intensity decreases as junction temperature rises.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing the peak at 611nm and the 17nm half-width.

5. Mechanical & Packaging Information

5.1 Outline Dimensions

The LED features a standard 5mm round radial-leaded package. Key dimensional notes include: all dimensions are in millimeters (with inches in parentheses), a general tolerance of ±0.25mm (.010"), a maximum resin protrusion under the flange of 1.0mm (.04"), and lead spacing measured at the point where leads exit the package. A detailed dimensional drawing is provided in the original datasheet for precise PCB layout.

5.2 Polarity Identification

Through-hole LEDs typically have a longer anode (+) lead and a flat spot or notch on the rim of the lens casing near the cathode (-) lead. Always refer to the datasheet diagram for the specific polarity marking of this component.

5.3 Packing Specifications

The LEDs are packed in anti-static bags. Standard quantities per bag are 1000, 500, 200, or 100 pieces. Ten bags are placed into an inner carton (e.g., totaling 10,000 pcs for 1000pc bags). Eight inner cartons are packed into an outer shipping carton (e.g., totaling 80,000 pcs). The last pack in a shipping lot may not be a full pack.

6. Soldering, Assembly & Handling Guidelines

Proper handling is critical to prevent damage and ensure long-term reliability.

6.1 Storage

For long-term storage, the ambient should not exceed 30°C or 70% relative humidity. LEDs removed from their original packaging should be used within three months. For extended storage outside the original pack, use a sealed container with desiccant or a nitrogen-desiccator.

6.2 Cleaning

If necessary, clean only with alcohol-based solvents like isopropyl alcohol. Avoid harsh or abrasive cleaners.

6.3 Lead Forming & Assembly

Bend leads at a point at least 3mm from the base of the LED lens. Do not use the lens base as a fulcrum. Forming must be done at room temperature and before soldering. During PCB insertion, use minimal clinch force to avoid mechanical stress on the epoxy body.

6.4 Soldering Process

Maintain a minimum clearance of 2mm between the solder point and the base of the lens. Never immerse the lens in solder.

• Soldering Iron: Maximum temperature 350°C. Maximum soldering time 3 seconds per lead (one time only).
• Wave Soldering: Maximum pre-heat temperature 100°C for up to 60 seconds. Maximum solder wave temperature 260°C for up to 5 seconds. The dipping position must be no lower than 2mm from the epoxy bulb base.
• Critical Note: Infrared (IR) reflow soldering is NOT suitable for this through-hole LED product. Excessive temperature or time can deform the lens or cause catastrophic failure.

6.5 Electrostatic Discharge (ESD) Protection

LEDs are sensitive to static electricity. Preventive measures include: using grounded wrist straps or anti-static gloves; ensuring all equipment, worktables, and storage racks are properly grounded; and using an ion blower to neutralize static charge that may accumulate on the plastic lens. A training and workstation checklist is recommended to maintain an ESD-safe environment.

7. Application Design Recommendations

7.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness when driving multiple LEDs in parallel, it is strongly recommended to use a individual current-limiting resistor in series with each LED (Circuit Model A). Driving LEDs in parallel directly from a voltage source (Circuit Model B) is not recommended, as small variations in the forward voltage (VF) characteristic between individual LEDs will cause significant differences in current and, consequently, brightness.

7.2 Calculating the Series Resistor

The value of the current-limiting resistor (R_s) is calculated using Ohm's Law: R_s = (V_supply - V_F) / I_F. For example, with a 5V supply, a typical V_F of 2.4V, and a desired I_F of 20mA: R_s = (5V - 2.4V) / 0.020A = 130 Ω. The resistor power rating should be at least P = I_F² * R_s = (0.020)² * 130 = 0.052W, so a standard 1/8W (0.125W) resistor is sufficient.

7.3 Thermal Management Considerations

While the power dissipation is low, the derating curve must be respected in high ambient temperature applications. Exceeding the maximum junction temperature will accelerate lumen depreciation and reduce operational lifetime. Ensure adequate airflow if the LED is operated at or near its maximum current rating in a confined space.

8. Technical Comparison and Differentiation

This AlInGaP amber LED offers distinct advantages over older technologies like GaAsP (Gallium Arsenide Phosphide). AlInGaP provides significantly higher luminous efficiency and better temperature stability, resulting in brighter and more consistent light output over a wide temperature range. The water-clear lens, as opposed to a diffused or tinted lens, maximizes the light output and creates a well-defined, sharp beam pattern with the specified 75-degree viewing angle, making it ideal for panel indicators where directed light is beneficial.

9. Frequently Asked Questions (FAQ)

9.1 Can I drive this LED without a series resistor?

No. Operating an LED directly from a voltage source is highly discouraged and will likely destroy the device due to uncontrolled current flow. The forward voltage is not a fixed threshold but a characteristic curve. A small increase in voltage beyond the typical VF can cause a large, damaging increase in current.

9.2 What is the difference between Peak and Dominant Wavelength?

Peak Wavelength (λp) is the physical wavelength at the highest intensity point on the spectral output curve. Dominant Wavelength (λd) is a calculated value based on human color perception (CIE chart) that best matches the perceived color. For monochromatic sources like this amber LED, they are often close, but λd is the more relevant parameter for color specification.

9.3 Can I use this LED for outdoor applications?

The datasheet states it is suitable for indoor and outdoor signs. However, for harsh outdoor environments with prolonged exposure to UV radiation, moisture, and extreme temperatures, additional design considerations are necessary, such as conformal coating on the PCB and ensuring the operating temperature remains within specification.

9.4 Why is there a binning system?

Manufacturing variations cause slight differences in performance between individual LEDs. Binning sorts them into groups with tightly controlled parameters (intensity, color). This allows designers to select bins that meet their specific uniformity requirements, especially important in multi-LED arrays or displays.

10. Practical Design Case Study

Scenario: Designing a control panel with 10 uniform amber status indicators powered from a 12V rail.

Design Steps:

1. Current Selection: Choose a drive current. 20mA is the standard test condition and provides good brightness.
2. Resistor Calculation: For a 12V supply and typical VF of 2.4V: R_s = (12V - 2.4V) / 0.020A = 480 Ω. The nearest standard value is 470 Ω. Re-calculating actual current: I_F = (12V - 2.4V) / 470Ω ≈ 20.4 mA (acceptable).
3. Power Rating: P_resistor = (0.0204A)² * 470Ω ≈ 0.195W. Use a 1/4W (0.25W) resistor for safety margin.
4. Binning for Uniformity: Specify a single, narrow intensity bin (e.g., M0: 520-680 mcd) and a single wavelength bin (e.g., H24: 603.0-606.5 nm) when ordering to ensure all 10 indicators look identical.
5. Layout: Place resistors on the PCB layout, maintaining the 2mm minimum solder-to-body distance. Ensure the polarity of each LED is correctly oriented.

11. Operating Principle

This LED is a semiconductor diode based on AlInGaP materials. When a forward voltage exceeding its characteristic forward voltage (VF) 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 AlInGaP layers determines the wavelength (color) of the emitted light, in this case, amber (~610 nm). The water-clear epoxy lens encapsulates the semiconductor chip, provides mechanical protection, and shapes the emitted light into the specified viewing angle.

12. Technology Trends

While surface-mount device (SMD) LEDs dominate modern high-density electronics, through-hole LEDs like this one remain relevant for applications requiring robustness, ease of manual assembly, repair, or high individual brightness from a single point source. The technology trend within through-hole LEDs continues to focus on increasing luminous efficacy (more light output per watt), improving color consistency through advanced binning, and enhancing reliability through better packaging materials. The shift towards higher-efficiency semiconductor materials like AlInGaP over older technologies is a clear example of this progression.