LTL-R14FGFAJ Through Hole LED Lamp Datasheet - T-1 Package - Orange/Yellow Green - 20mA - 52mW - English Technical Documentation

1. Product Overview

This document details the specifications for the LTL-R14FGFAJ, a through-hole LED lamp designed for status indication and signaling applications. The device is offered in two distinct color variants: Orange and Yellow Green, utilizing AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology for high efficiency and reliable performance. The LED is housed in a standard T-1 type package with a white diffused lens, providing a wide viewing angle suitable for various electronic equipment.

1.1 Core Features and Advantages

• High Efficiency & Low Power Consumption: Designed for optimal luminous output while minimizing energy use, making it suitable for battery-powered or energy-conscious applications.
• Environmental Compliance: The product is lead-free and fully compliant with RoHS (Restriction of Hazardous Substances) directives.
• Standard Package: The familiar T-1 (3mm) through-hole package ensures easy integration into existing PCB designs and prototyping boards.
• Wide Viewing Angle: The white diffused lens creates a uniform light distribution, enhancing visibility from various angles.

1.2 Target Applications and Markets

This LED is versatile and finds use across multiple industries requiring clear, reliable visual indicators. Primary application areas include:

• Communication Equipment: Status lights on routers, modems, and network switches.
• Computer Peripherals: Power, activity, and mode indicators on keyboards, monitors, and external drives.
• Consumer Electronics: Indicator lights on audio/video equipment, home appliances, and toys.
• Home Appliances: Operational status indicators on microwaves, washing machines, and coffee makers.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

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

• Power Dissipation (P_D): 52 mW for both Orange and Yellow Green variants. This parameter is crucial for thermal management.
• DC Forward Current (I_F): 20 mA continuous. Exceeding this current will significantly reduce lifespan and may cause failure.
• Peak Forward Current: 60 mA (pulse width ≤10 μs, duty cycle ≤1/10). Suitable for brief, high-intensity pulses.
• Operating Temperature Range: -30°C to +85°C. Ensures functionality in a wide range of environmental conditions.
• Storage Temperature Range: -40°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm from the LED body. Critical for assembly process control.

2.2 Electrical and Optical Characteristics

These parameters are measured at an ambient temperature (T_A) of 25°C and define the typical performance of the device.

• Luminous Intensity (I_V): For the Orange LED, the typical value is 140 mcd at I_F=20mA. The Yellow Green variant's intensity is specified within the binning table. Measurement follows the CIE photopic eye-response curve.
• Viewing Angle (2θ_1/2): 100 degrees for both colors. This is the full angle at which intensity drops to half its axial value, indicating a very wide beam.
• Peak Wavelength (λ_P): Orange: 611 nm (typical). Yellow Green: 575 nm (typical). This is the wavelength of maximum spectral emission.
• Dominant Wavelength (λ_d): Defines the perceived color. Orange: 598-612 nm range. Yellow Green: 565-571 nm range. Specific values are controlled via binning.
• Spectral Half-Width (Δλ): Orange: 17 nm (typical). Yellow Green: 15 nm (typical). This indicates the spectral purity of the emitted light.
• Forward Voltage (V_F): 2.1V to 2.6V at I_F=20mA for both colors. Important for calculating series resistor values in drive circuits.
• Reverse Current (I_R): 10 μA maximum at V_R=5V. Important Note: The LED is not designed for reverse bias operation; this test condition is for characterization only.

3. Binning System Specification

To ensure color and brightness consistency in production, LEDs are sorted into bins. The LTL-R14FGFAJ uses a two-dimensional binning system.

3.1 Luminous Intensity Binning

Both Orange and Yellow Green LEDs are grouped into three intensity bins (AB, CD, EF), each with a defined minimum and maximum luminous intensity measured at 20mA. Tolerance for each bin limit is ±30%.

• Bin AB: 23 - 50 mcd
• Bin CD: 50 - 85 mcd
• Bin EF: 85 - 140 mcd

3.2 Dominant Wavelength Binning

LEDs are also binned by their dominant wavelength to control color consistency. Tolerance for each bin limit is ±1 nm.

• Yellow Green Wavelength Bins:
  • Bin 1: 565.0 - 568.0 nm
  • Bin 2: 568.0 - 571.0 nm
• Orange Wavelength Bins:
  • Bin 3: 598.0 - 605.0 nm
  • Bin 4: 605.0 - 612.0 nm

When ordering, a complete part number specifying both intensity and wavelength bins is typically required to guarantee specific performance characteristics.

4. Mechanical and Packaging Information

4.1 Outline Dimensions

The LED conforms to the standard T-1 (3mm) radial leaded package. Key dimensional notes include:

• All dimensions are in millimeters (inches provided for reference).
• Standard tolerance is ±0.25mm unless otherwise specified.
• Maximum resin protrusion under the flange is 1.0mm.
• Lead spacing is measured where leads exit the package body.

4.2 Polarity Identification

The cathode (negative lead) is typically identified by a flat spot on the LED lens rim and/or by being the shorter lead. Always refer to the manufacturer's marking diagram for confirmation before assembly.

4.3 Packing Specification

The LEDs are packed in anti-static bags to prevent ESD damage. Standard packing quantities are:

• 1000, 500, 200, or 100 pieces per packing bag.
• 10 packing bags are placed in an inner carton (total 10,000 pcs max).
• 8 inner cartons are packed in an outer shipping carton (total 80,000 pcs max).

5. Assembly, Soldering, and Handling Guidelines

5.1 Storage Conditions

For long-term reliability, store LEDs in an environment not exceeding 30°C and 70% relative humidity. If removed from the original sealed, moisture-barrier bag, use within three months. For extended storage outside the original packaging, use a sealed container with desiccant or a nitrogen-filled desiccator.

5.2 Lead Forming and PCB Assembly

• Bend leads at a point at least 3mm from the base of the LED lens.
• Do not use the LED body as a fulcrum during bending.
• Perform all lead forming at room temperature and before soldering.
• During PCB insertion, use minimal clinching force to avoid mechanical stress on the epoxy lens.

5.3 Soldering Recommendations

Maintain a minimum distance of 2mm from the base of the lens to the solder point. Never immerse the lens in solder.

• Hand Soldering (Iron):
  • Temperature: 350°C maximum.
  • Time: 3 seconds maximum per lead.
  • Limit to one soldering cycle.
• Wave Soldering:
  • Pre-heat Temperature: 150°C maximum for 120 seconds max.
  • Solder Wave (Peak): 270°C ±5°C maximum.
  • Contact Time: 6 seconds maximum.
  • Dipping Position: No lower than 2mm from the lens base.

Warning: Excessive temperature or time can deform the lens or cause catastrophic LED failure.

5.4 Electrostatic Discharge (ESD) Protection

AlInGaP LEDs are sensitive to electrostatic discharge. Always:

• Use a grounded wrist strap or anti-static gloves when handling.
• Ensure all workstations, tools, and equipment are properly grounded.
• Use an ionizer to neutralize static charge that may build up on the plastic lens.

6. Drive Circuit Design and Application Notes

6.1 Recommended Drive Method

LEDs are current-driven devices. To ensure uniform brightness, especially when multiple LEDs are used in parallel, it is strongly recommended to drive each LED with its own current-limiting resistor connected in series (Circuit A).

Avoid connecting LEDs directly in parallel without individual resistors (Circuit B), as small variations in their forward voltage (V_F) characteristics will cause significant differences in current sharing and, consequently, uneven brightness.

6.2 Series Resistor Calculation

The value of the current-limiting resistor (R_S) is calculated using Ohm's Law: R_S = (V_Supply - V_F) / I_F

Where:

• V_Supply is the power supply voltage.
• V_F is the LED forward voltage (use max value of 2.6V for a conservative design).
• I_F is the desired forward current (20 mA max continuous).

Example: For a 5V supply: R_S = (5V - 2.6V) / 0.020A = 120 Ω. The nearest standard value (e.g., 120Ω or 150Ω) can be used, adjusting the current slightly.

6.3 Thermal Considerations

While the power dissipation is low (52mW), ensuring adequate spacing between LEDs on a PCB and avoiding placement near other heat-generating components will help maintain optimal light output and longevity, especially when operating at the upper end of the temperature range.

7. Performance Curves and Typical Characteristics

While specific graphs are not detailed in the provided text, typical performance curves for such LEDs would include:

• I-V (Current-Voltage) Curve: Shows the exponential relationship between forward voltage and current, highlighting the turn-on voltage (~2.0V).
• Relative Luminous Intensity vs. Forward Current: Demonstrates how light output increases with current, typically in a near-linear relationship within the recommended operating range.
• Relative Luminous Intensity vs. Ambient Temperature: Shows the decrease in light output as junction temperature rises, a key consideration for high-temperature environments.
• Spectral Distribution: A plot of relative intensity vs. wavelength, showing the peak (λ_P) and the spectral half-width (Δλ).
• Viewing Angle Pattern: A polar plot illustrating the spatial distribution of light intensity, confirming the wide 100-degree viewing angle.

Designers should consult the full datasheet from the manufacturer for these graphical representations to make informed design decisions regarding drive current, thermal management, and optical design.

8. Comparison and Selection Guidance

8.1 Orange vs. Yellow Green Selection

• Orange (611nm peak): Offers high luminous intensity (up to 140 mcd typ.) and is often chosen for warning or attention-grabbing indicators. Its longer wavelength can sometimes offer better visibility in certain ambient light conditions compared to red.
• Yellow Green (~575nm peak): Positioned near the peak sensitivity of the human eye (555nm), providing high perceived brightness for a given radiant power. Often used for general status indicators where clear, neutral signaling is required.

8.2 Key Differentiators of AlInGaP Technology

Compared to older technologies like standard GaP (Gallium Phosphide), AlInGaP LEDs used in this product offer:

• Higher Efficiency: More lumens per watt, leading to brighter output at the same current.
• Better Temperature Stability: Generally exhibit less reduction in light output with increasing temperature.
• Superior Color Saturation: Can produce brighter and more saturated colors in the red-orange-yellow spectrum.

9. Frequently Asked Questions (FAQs)

Q: Can I drive this LED at 30mA for more brightness?
A: No. The absolute maximum continuous forward current is 20mA. Exceeding this rating will drastically reduce the LED's lifespan and may cause immediate failure due to overheating.

Q: Why is a series resistor necessary even with a constant current source?
A> A true constant current source does not require a series resistor for current regulation. However, in most practical applications using voltage sources (like a 5V or 3.3V rail), a series resistor is the simplest and most cost-effective method to set and limit the current through the LED.

Q: What does the ±30% tolerance on luminous intensity bins mean?
A> It means that the actual tested intensity of an LED labeled in a specific bin (e.g., EF: 85-140 mcd) could be up to 30% higher or lower than the stated bin limits. This is a test tolerance, not a production spread. The binning process itself sorts LEDs into these ranges.

Q: Is this LED suitable for outdoor use?
A> The datasheet states it is good for indoor and outdoor signs. However, for prolonged outdoor exposure, additional design considerations are needed, such as conformal coating on the PCB to protect against moisture and UV-resistant lens material (which this white diffused lens may provide). Verify specific environmental ratings with the manufacturer for critical applications.

Q: How do I identify the anode and cathode?
A> Typically, the cathode (negative) lead is shorter and may be marked by a flat edge on the LED's plastic flange. Always check the manufacturer's datasheet diagram for the specific marking scheme.