LTL403FDBK Orange LED Datasheet - Through Hole Lamp - 5mm Round - 2.4V - 20mA - English Technical Document

1. Product Overview

The LTL403FDBK is a through-hole mounted LED lamp designed for general-purpose indicator applications. It utilizes an AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor material to produce an orange light output. This device is characterized by its solid-state reliability, long operational life, and compatibility with integrated circuit drive levels, making it suitable for use as a level indicator or status light in various electronic equipment.

The product is manufactured as a lead (Pb) free component and is compliant with the RoHS (Restriction of Hazardous Substances) directive. Its primary package is a standard 5mm round, water-clear lens format, which provides a wide viewing angle for visibility from multiple directions.

1.1 Core Advantages

• Environmental Compliance: Lead-free and RoHS compliant construction.
• High Reliability: Solid-state design ensures long operational lifespan and durability.
• Ease of Integration: Compatible with standard IC logic levels, simplifying circuit design.
• Optical Performance: Water-clear lens provides good light output and a defined viewing angle.

2. Technical Parameter Deep Dive

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): 72 mW maximum. This is the total power the device can safely dissipate as heat.
• Peak Forward Current (I_FP): 60 mA maximum, under pulsed conditions (1/10 duty cycle, 0.1ms pulse width).
• DC Forward Current (I_F): 20 mA maximum continuous current.
• Operating Temperature Range (T_A): -40°C to +85°C. The device is rated for industrial temperature environments.
• Storage Temperature Range (T_stg): -40°C to +100°C.
• Lead Soldering Temperature: 260°C for 5 seconds, measured 2.0 mm from the LED body.

2.2 Electrical & Optical Characteristics

These parameters are specified at an ambient temperature (T_A) of 25°C and a forward current (I_F) of 10 mA, unless otherwise noted.

• Luminous Intensity (I_v): 50 mcd (Min), 140 mcd (Typ), 240 mcd (Max). This is the perceived brightness of the LED. The guarantee includes a ±15% tolerance.
• Viewing Angle (2θ_1/2): 40 degrees (Typical). This is the full angle at which the luminous intensity drops to half of its axial (on-axis) value.
• Peak Emission Wavelength (λ_p): 611 nm (Typical). This is the wavelength at which the spectral output is strongest.
• Dominant Wavelength (λ_d): 598.0 nm (Min), 605.0 nm (Typ), 613.5 nm (Max). This is the single wavelength that defines the perceived color of the LED, derived from the CIE chromaticity diagram.
• Spectral Line Half-Width (Δλ): 17 nm (Typical). This indicates the spectral purity or bandwidth of the emitted light.
• Forward Voltage (V_F): 1.9 V (Min), 2.4 V (Typ). The voltage drop across the LED when conducting the specified forward current.
• Reverse Current (I_R): 100 μA maximum at a reverse voltage (V_R) of 5V. The device is not designed for reverse operation; this parameter is for test purposes only.

3. Binning System Explanation

The LEDs are sorted into bins based on key optical parameters to ensure consistency within an application. The binning tolerance is applied to the limits of each bin.

3.1 Luminous Intensity Binning

Units: mcd @ 10mA. Tolerance per bin limit: ±15%.

• Bin CD: Minimum 50 mcd, Maximum 85 mcd.
• Bin EF: Minimum 85 mcd, Maximum 140 mcd.
• Bin GH: Minimum 140 mcd, Maximum 240 mcd.

3.2 Dominant Wavelength Binning

Units: nm @ 10mA. Tolerance per bin limit: ±1 nm.

• Bin H22: 598.0 nm to 600.0 nm.
• Bin H23: 600.0 nm to 603.0 nm.
• Bin H24: 603.0 nm to 606.5 nm.
• Bin H25: 606.5 nm to 610.0 nm.
• Bin H26: 610.0 nm to 613.5 nm.

This binning allows designers to select LEDs with very specific color points, which is critical for applications requiring color matching or specific aesthetic requirements.

4. Performance Curve Analysis

The datasheet references typical performance curves which are essential for understanding device behavior under varying conditions. While the specific graphs are not reproduced in text, their implications are analyzed below.

4.1 Forward Current vs. Forward Voltage (I-V Curve)

The I-V characteristic is non-linear, typical of a diode. The specified forward voltage (V_F) of 2.4V at 10mA is a key design parameter. As current increases, V_F will increase slightly due to the series resistance of the semiconductor and leads. This curve is crucial for designing the current-limiting resistor in the drive circuit.

4.2 Luminous Intensity vs. Forward Current

Luminous intensity is approximately proportional to the forward current over a certain range. Operating above the absolute maximum DC current (20mA) is not recommended as it can lead to accelerated degradation, reduced lifetime, and potential catastrophic failure. The relationship may become sub-linear at very high currents due to heating effects.

4.3 Spectral Distribution

The spectral output curve shows a peak around 611 nm (orange) with a typical half-width of 17 nm. The dominant wavelength, used for binning, is calculated from this spectrum to define the color point. The narrow bandwidth is characteristic of AlInGaP technology, providing good color saturation.

4.4 Temperature Dependence

LED performance is temperature-sensitive. Typically, the forward voltage (V_F) has a negative temperature coefficient (decreases with increasing temperature), while luminous intensity decreases with increasing junction temperature. Operating within the specified temperature range is critical for maintaining performance and reliability.

5. Mechanical & Packaging Information

5.1 Package Dimensions

The device is a standard 5mm round through-hole LED. Key dimensional notes include:

• All dimensions are in millimeters (inches provided for reference).
• Standard tolerance is ±0.25mm (±0.010\") unless otherwise specified.
• Maximum protrusion of resin under the flange is 1.0mm (0.04\").
• Lead spacing is measured at the point where leads emerge from the package body.

5.2 Polarity Identification

For through-hole LEDs, the cathode is typically identified by a flat spot on the lens rim or by the shorter lead. The datasheet should be consulted for the specific polarity marking of this part number. Correct polarity is essential for operation.

6. Soldering & Assembly Guidelines

6.1 Lead Forming

• Bending must be performed at a point at least 3mm from the base of the LED lens.
• The base of the lead frame must not be used as a fulcrum during bending.
• Lead forming must be done at normal room temperature and before the soldering process.
• During PCB assembly, use the minimum clinching force necessary to avoid imposing excessive mechanical stress on the LED package.

6.2 Soldering Process

• A minimum clearance of 2mm must be maintained between the base of the lens and the soldering point.
• Immersing the lens in solder must be avoided.
• No external stress should be applied to the leads while the LED is at elevated temperature from soldering.

Recommended Soldering Conditions:

• Soldering Iron: Maximum temperature 350°C, maximum time 3 seconds (one time only).
• Wave Soldering:
  • Pre-heat: Maximum 100°C for up to 60 seconds.
  • Solder Wave: Maximum 260°C for up to 5 seconds.

Important Note: Infrared (IR) reflow soldering is not a suitable process for this through-hole type LED lamp. Excessive temperature or time can cause lens deformation or device failure.

7. Packaging & Ordering Information

7.1 Packaging Specification

The LEDs are packed in multiple tiers for bulk handling:

• Primary Pack: 1000, 500, 200, or 100 pieces per packing bag.
• Inner Carton: 10 packing bags per inner carton, totaling 10,000 pieces.
• Outer Carton: 8 inner cartons per outer carton, totaling 80,000 pieces.

8. Application Recommendations

8.1 Intended Use & Limitations

This LED is intended for ordinary electronic equipment including office equipment, communication devices, and household applications. It is not designed for applications where exceptional reliability is required, particularly where failure could jeopardize life or health (e.g., aviation, medical systems, critical safety devices). Consultation with the supplier is required for such high-reliability applications.

8.2 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness when multiple LEDs are connected in parallel, it is strongly recommended to use a individual current-limiting resistor in series with each LED (Circuit Model A).

Avoid connecting LEDs directly in parallel without individual resistors (Circuit Model B). Small variations in the forward voltage (V_F) characteristic between individual LEDs can cause significant current imbalance, leading to uneven brightness and potential over-current in some devices.

The series resistor value (R_s) can be calculated using Ohm's Law: R_s = (V_supply - V_F) / I_F, where V_F is the LED forward voltage (use typical or max value for design margin) and I_F is the desired forward current (e.g., 10mA).

8.3 Electrostatic Discharge (ESD) Protection

LEDs are susceptible to damage from electrostatic discharge. Recommended precautions include:

• Use conductive wrist straps or anti-static gloves when handling.
• Ensure all equipment, workstations, and storage racks are properly grounded.
• Use ionizers to neutralize static charge that may build up on the plastic lens.

9. Storage & Handling

• Storage Environment: Should not exceed 30°C and 70% relative humidity.
• Shelf Life: LEDs removed from their original packaging should be used within three months.
• Long-Term Storage: For extended storage out of original packaging, store in a sealed container with desiccant or in a nitrogen-purged desiccator.
• Cleaning: If necessary, clean only with alcohol-based solvents like isopropyl alcohol.

10. Technical Comparison & Considerations

10.1 Material Technology: AlInGaP

The use of Aluminum Indium Gallium Phosphide (AlInGaP) as the active semiconductor material offers advantages for orange, red, and yellow LEDs. Compared to older technologies, AlInGaP typically provides higher luminous efficiency, better temperature stability, and longer operational life. The 611 nm peak wavelength and narrow spectral width are direct results of this material system.

10.2 Through-Hole vs. Surface Mount

This is a through-hole device, meaning it is designed for insertion into plated-through holes on a PCB and soldered on the opposite side. This technology offers high mechanical strength and is often preferred for prototypes, educational kits, or applications where manual assembly or repair is anticipated. It is being increasingly replaced by Surface Mount Device (SMD) packages in high-volume, automated manufacturing due to SMD's smaller size and lower profile.

11. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive this LED at 20mA continuously?
A1: Yes, 20mA is the Absolute Maximum DC Forward Current rating. For reliable long-term operation, it is common practice to derate this value. Operating at the typical test condition of 10mA or slightly above (e.g., 15-18mA) will extend lifespan and improve stability.

Q2: Why is there a ±15% tolerance on the luminous intensity bin limits?
A2: This accounts for measurement system variations and ensures the binning process is practically achievable. It means a LED labeled in the \"EF\" bin (85-140 mcd) could actually measure as low as 72.25 mcd or as high as 161 mcd at the extremes of the tolerance. Designers must account for this spread in their optical designs.

Q3: What happens if I solder too close to the LED body?
A3: Excessive heat conducted up the leads can damage the internal wire bonds, degrade the semiconductor chip, or melt/deform the plastic lens. This can cause immediate failure or significantly reduce the LED's lifetime. Always maintain the 2mm minimum clearance.

Q4: Can I use this for battery-powered devices?
A4: Yes, its typical forward voltage of 2.4V at 10mA makes it suitable for operation from a 3V coin cell (like CR2032) or two AA/AAA batteries in series (3V). A series resistor is mandatory to limit the current from the higher battery voltage.

12. Design-in Case Study

Scenario: Designing a panel with four orange status indicators for a consumer electronics product powered by a 5V DC supply rail.

Design Steps:

1. Current Selection: Choose a forward current (I_F) of 15mA for a good balance of brightness and longevity, well below the 20mA maximum.
2. Voltage Reference: Use the maximum forward voltage (V_F) from the datasheet for a conservative design. While typical is 2.4V, using a value like 2.6V provides margin.
3. Resistor Calculation: R_s = (V_supply - V_F) / I_F = (5V - 2.6V) / 0.015A = 160 Ohms. The nearest standard E24 value is 160Ω or 150Ω.
4. Power Rating for Resistor: P_R = I_F² * R_s = (0.015)² * 160 = 0.036W. A standard 1/8W (0.125W) or 1/10W resistor is more than sufficient.
5. Circuit Layout: Use four independent circuits (LED + 160Ω resistor) connected in parallel to the 5V rail. Do not connect the four LEDs to a single shared resistor.
6. PCB Layout: Ensure the LED mounting holes maintain the 3mm lead bend distance and that solder pads are placed >2mm from the LED body outline on the PCB.

13. Operational Principle

Light Emitting Diodes (LEDs) are semiconductor p-n junction devices. When a forward voltage exceeding the junction's built-in potential is applied, electrons from the n-type region and holes from the p-type region are injected into the active region where they recombine. In this specific AlInGaP LED, the energy released during this electron-hole recombination is primarily in the form of photons (light) with an energy corresponding to the orange part of the visible spectrum (~611 nm wavelength). The water-clear epoxy lens serves to protect the semiconductor chip, shape the light output beam, and enhance light extraction from the material.

14. Technology Trends

The general trend in LED packaging is towards smaller form factors and surface-mount technology (SMD) for automated assembly. However, through-hole LEDs like the 5mm round package remain relevant for hobbyist markets, educational purposes, legacy product support, and applications requiring very high mechanical bond strength. Advancements in AlInGaP and related III-V semiconductor materials continue to push the limits of efficiency (lumens per watt) and reliability. Furthermore, there is ongoing development in phosphor-converted technologies to achieve a wider gamut of colors from a single semiconductor material, though for monochromatic orange LEDs, direct-emitting AlInGaP remains the dominant and most efficient technology.