LTL-R14FGSAJ LED Lamp Datasheet - T-1 Package - 2.0V Typ - 20mA - Yellow Green/Yellow - English Technical Document

1. Product Overview

This document details the specifications for the LTL-R14FGSAJ, a through-hole LED lamp. Through-hole LEDs are offered in a variety of packages such as 3 mm, 4mm, 5mm, rectangular, and cylinder which are suitable for all applications requiring status indication. Several intensity and viewing angle choices are available in each color for design flexibility.

1.1 Features

• Low power consumption & High efficiency
• Lead free & RoHS Compliant
• T-1 type package White Diffused lens.
• AlInGaP Yellow Green and Yellow lamp with white diffused lens.

1.2 Applications

• Communication equipment
• Computer peripherals
• Consumer electronics
• Home appliances

2. Outline Dimensions

The LED features a standard T-1 (3mm) package with a white diffused lens. The leads are designed for through-hole mounting on printed circuit boards (PCBs).

Notes:

1. All dimensions are in millimeters (inches).
2. Tolerance is ±0.25mm (.010") unless otherwise noted.
3. Protruded resin under flange is 1.0mm (.04") max.
4. Lead spacing is measured where the leads emerge from the package.
5. Specifications are subject to change without notice.

3. Absolute Maximum Ratings

Ratings are specified at an ambient temperature (TA) of 25°C. Exceeding these values may cause permanent damage to the device.

4. Electrical / Optical Characteristics

Characteristics are measured at an ambient temperature (TA) of 25°C.

NOTES:

1. Luminous intensity is measured with a light sensor and filter combination that approximates the CIE eye-response curve.
2. θ1/2 is the off-axis angle at which the luminous intensity is half the axial luminous intensity.
3. The dominant wavelength, λd is derived from the CIE chromaticity diagram and represents the single wavelength which defines the color of the device.
4. Iv guarantee must be included with ±30% testing tolerance.
5. Reverse voltage (VR) condition is applied for IR test only. The device is not designed for reverse operation.
6. Reverse current is controlled by dice source.

5. Typical Electrical / Optical Characteristics Curves

The datasheet includes typical performance curves measured at 25°C ambient temperature unless otherwise noted. These curves graphically represent the relationship between forward current (IF) and luminous intensity (Iv), forward voltage (VF), and the impact of ambient temperature on luminous intensity. Analyzing these curves is crucial for understanding the LED's behavior under different operating conditions, allowing designers to optimize drive current for desired brightness while managing power dissipation and thermal effects.

6. Binning System Specification

The LEDs are sorted into bins based on luminous intensity and dominant wavelength to ensure color and brightness consistency within an application.

6.1 Luminous Intensity Binning

Note: Tolerance of each bin limit is ±30%.

6.2 Dominant Wavelength Binning

Note: Tolerance of each bin limit is ±1nm.

7. Packaging Specification

The LEDs are packaged for bulk handling and shipping:

• 1000, 500, 200, or 100 pieces per packing bag.
• 10 packing bags are placed per inner carton, totaling 10,000 pieces.
• 8 inner cartons are packed per outer carton, totaling 80,000 pieces.
• In every shipping lot, only the last pack will be non-full packing.

8. Cautions and Application Guidelines

8.1 Application

This LED lamp is suitable for application in indoor and outdoor signs, as well as ordinary electronic equipment requiring status indication.

8.2 Storage

The storage ambient for the LEDs should not exceed 30°C temperature or 70% relative humidity. It is recommended that LEDs out of their original packaging are used within three months. For extended storage out of their original packaging, it is recommended that the LEDs be stored in a sealed container with appropriate desiccant or in desiccators with nitrogen ambient.

8.3 Cleaning

Use alcohol-based cleaning solvents such as isopropyl alcohol to clean the LEDs if necessary.

8.4 Lead Forming & Assembly

During lead forming, the leads should be bent at a point at least 3mm from the base of the LED lens. Do not use the base of the lead frame as a fulcrum during forming. Lead forming must be done before soldering, at normal temperature. During assembly on PCB, use the minimum clinch force possible to avoid excessive mechanical stress on the package.

8.5 Soldering

When soldering, leave a minimum of 2mm clearance from the base of the lens to the soldering point. Dipping the lens into the solder must be avoided. Do not apply any external stress to the lead frame during soldering while the LED is at high temperature.

Recommended soldering conditions:

Soldering Iron: Temperature: 350°C Max. Soldering time: 3 seconds Max. (one time only). Position: No closer than 2mm from the base of the epoxy bulb.

Wave Soldering: Pre-heat: 100°C Max. Pre-heat time: 60 seconds Max. Solder wave: 260°C Max. Soldering time: 5 seconds Max. Dipping Position: No lower than 2mm from the base of the epoxy bulb.

Note: Excessive soldering temperature and/or time might result in deformation of the LED lens or catastrophic failure of the LED. IR reflow is not a suitable process for through-hole type LED lamp products.

8.6 Drive Method

An LED is a current-operated device. In order to ensure intensity uniformity on multiple LEDs connected in parallel in an application, it is strongly recommended that a current limiting resistor be incorporated in the drive circuit, in series with each LED. Driving LEDs directly from a voltage source without a series resistor (connecting multiple LEDs in parallel) is not recommended, as the brightness of each LED might appear different due to the natural variations in the forward voltage (I-V) characteristics of individual LEDs. The series resistor stabilizes the current through each LED, ensuring consistent brightness and protecting the LED from current spikes.

8.7 ESD (Electrostatic Discharge) Protection

Static electricity or power surge can damage the LED. Suggestions to prevent ESD damage include:

• Use a conductive wrist band or anti-static glove when handling these LEDs.
• All devices, equipment, and machinery must be properly grounded.
• Work tables, storage racks, etc. should be properly grounded.
• Use an ion blower to neutralize the static charge which might have built up on the surface of the LED's plastic lens as a result of friction between LEDs during storage and handling.

9. Technical Analysis and Design Considerations

9.1 Photometric and Colorimetric Analysis

The LTL-R14FGSAJ uses AlInGaP (Aluminum Indium Gallium Phosphide) technology for its Yellow Green and Yellow emissions. AlInGaP LEDs are known for their high efficiency and good color purity in the amber to red spectrum. The white diffused lens serves to widen the viewing angle to a typical 110 degrees and softens the appearance of the light point, making it ideal for status indicators where wide-angle visibility is desired. The dominant wavelength bins ensure color consistency, which is critical in applications where multiple LEDs are used together and must match visually.

9.2 Thermal Management Considerations

With a maximum power dissipation of 52mW and a DC forward current of 20mA, thermal management is generally straightforward for these indicators. However, designers must consider the operating temperature range (-40°C to +85°C). At higher ambient temperatures, the luminous output will decrease, and the forward voltage will also shift slightly. For applications operating consistently at high temperatures, derating the forward current may be necessary to maintain long-term reliability. The absolute maximum rating for lead soldering temperature (260°C for 5 seconds) provides clear guidelines for PCB assembly processes.

9.3 Circuit Design Implementation

The typical forward voltage (VF) of 2.0V at 10mA is a key parameter for circuit design. To calculate the required series resistor (R_s) when powering the LED from a supply voltage (V_supply), use Ohm's Law: R_s = (V_supply - VF) / I_F. For example, with a 5V supply and a target current of 10mA: R_s = (5V - 2.0V) / 0.01A = 300 Ohms. The power rating of the resistor should be at least P = I_F^2 * R_s = (0.01)^2 * 300 = 0.03W, so a standard 1/8W or 1/10W resistor is sufficient. This simple current-limiting circuit is essential for stable operation and longevity.

9.4 Comparison with Alternative Technologies

Compared to older GaAsP (Gallium Arsenide Phosphide) yellow LEDs, AlInGaP technology offers significantly higher luminous efficiency, resulting in brighter output for the same drive current. The wide 110-degree viewing angle provided by the diffused lens is a distinct advantage over clear-lens LEDs that have narrower viewing angles, making the LTL-R14FGSAJ better suited for applications where the indicator needs to be seen from various angles. The through-hole package offers mechanical robustness and ease of manual assembly or prototyping compared to surface-mount device (SMD) alternatives, though SMDs save board space in high-volume automated production.

9.5 Application-Specific Recommendations

For communication equipment (routers, modems), these LEDs provide clear link/activity status. In consumer electronics and home appliances (power buttons, mode indicators), the diffused light is aesthetically pleasing. When used in outdoor signage, designers must ensure the housing provides adequate environmental protection (IP rating) as the LED itself is not waterproof. For battery-powered devices, the low forward voltage and ability to operate effectively at currents below 10mA (refer to the IV curve) help conserve energy. When designing panels with multiple indicators, specifying LEDs from the same intensity and wavelength bin is crucial for a uniform appearance.

9.6 Reliability and Lifespan Factors

The lifespan of an LED is primarily determined by operating conditions, especially junction temperature. Adhering to the absolute maximum ratings for current and temperature is paramount. The storage guidelines prevent moisture absorption, which could lead to "popcorning" or delamination during soldering. Proper ESD handling prevents latent defects that may cause premature failure. By following the soldering, driving, and handling guidelines in this datasheet, the LED can achieve its intended operational lifetime, which is typically tens of thousands of hours for indicator applications.

10. Frequently Asked Questions (FAQs)

Q: Can I drive this LED at its maximum DC current of 20mA continuously?
A: Yes, but only within the specified operating temperature range. For maximum reliability, especially in high ambient temperatures, operating at a lower current (e.g., 10-15mA) is recommended, as it reduces internal heating and stress on the device.

Q: What is the difference between Peak Wavelength (λP) and Dominant Wavelength (λd)?
A: Peak Wavelength is the wavelength at which the emitted optical power is maximum. Dominant Wavelength is the single wavelength perceived by the human eye that best represents the color of the light, calculated from the CIE chromaticity coordinates. λd is more relevant for color specification.

Q: Why is a series resistor mandatory?
A: LEDs have an exponential I-V relationship. A small increase in voltage causes a large increase in current, which can quickly exceed the maximum rating and destroy the LED. A series resistor makes the current primarily dependent on the resistor value and supply voltage, providing a simple and effective form of current regulation.

Q: Can I use this LED for backlighting a small panel?
A: While possible, its wide viewing angle and diffused lens make it better suited for direct viewing as a status indicator. For even panel backlighting, LEDs with a narrower viewing angle or side-view packages are often more appropriate.

Q: How do I interpret the binning codes when ordering?
A: Specify the desired combination of Luminous Intensity Bin (e.g., A or B) and Dominant Wavelength Bin (e.g., 1 or 2) for the required color (Yellow Green or Yellow) to ensure you receive LEDs with consistent performance characteristics for your application.