LTL763ENAK Through Hole LED Lamp Datasheet - Red 624nm - 20mA - 430-1880mcd - English Technical Document

1. Product Overview

This document provides the complete technical specifications for a high-performance through-hole LED lamp. Designed for status indication and signaling applications, this component offers a combination of high luminous output, reliability, and design flexibility. The device features a red chip paired with a water-clear lens, resulting in a distinct 624nm dominant wavelength output. Its through-hole package design allows for versatile mounting on printed circuit boards (PCBs) or panels, making it suitable for a wide range of electronic assemblies.

The core advantages of this LED include its high luminous intensity, which can reach up to 1880 millicandelas (mcd), and its low power consumption. It is a lead-free (Pb-free) product compliant with the Restriction of Hazardous Substances (RoHS) directive. The primary target markets for this component span communication equipment, computer peripherals, consumer electronics, home appliances, and industrial control systems where clear, bright visual indicators are required.

2. Technical Parameter Deep-Dive

2.1 Absolute Maximum Ratings

The device is characterized under an ambient temperature (TA) of 25°C. Exceeding these limits may cause permanent damage.

• Power Dissipation: 50 mW maximum.
• Peak Forward Current: 60 mA maximum, applicable under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10ms).
• DC Forward Current: 30 mA maximum for continuous operation.
• Current Derating: Linear derating from 30°C at a rate of 0.27 mA/°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 2.0mm from the LED body.

2.2 Electrical & Optical Characteristics

Key performance parameters are measured at TA=25°C with a forward current (IF) of 20mA, unless otherwise specified.

• Luminous Intensity (Iv): Ranges from a minimum of 430 mcd to a maximum of 1880 mcd. The typical value is 900 mcd. Measurement follows the CIE eye-response curve, and guaranteed values include a ±15% testing tolerance.
• Viewing Angle (2θ1/2): 110 degrees. This is the full angle at which the luminous intensity drops to half of its axial (on-axis) value, defining the beam spread.
• Peak Emission Wavelength (λp): 632 nm.
• Dominant Wavelength (λd): 624 nm. This is the single wavelength derived from the CIE chromaticity diagram that defines the perceived color of the LED.
• Spectral Line Half-Width (Δλ): 20 nm, indicating the spectral purity of the emitted red light.
• Forward Voltage (VF): Typically 2.5V, with a maximum of 2.5V at IF=20mA.
• Reverse Current (IR): 100 μA maximum when a reverse voltage (VR) of 5V is applied. Important: The device is not designed for operation under reverse bias; this test condition is for characterization only.

3. Binning System Specification

To ensure consistency in brightness levels for production applications, the LEDs are sorted into bins based on their luminous intensity measured at 20mA. The bin code is marked on each packing bag.

• Bin Code M: Luminous Intensity from 430 mcd to 620 mcd.
• Bin Code N: Luminous Intensity from 620 mcd to 900 mcd.
• Bin Code P: Luminous Intensity from 900 mcd to 1300 mcd.
• Bin Code Q: Luminous Intensity from 1300 mcd to 1880 mcd.

A tolerance of ±15% applies to the limits of each bin. This system allows designers to select the appropriate brightness grade for their specific application needs, ensuring visual uniformity when multiple LEDs are used.

4. Performance Curve Analysis

Typical performance curves illustrate the relationship between key parameters. These curves are essential for understanding device behavior under different operating conditions.

• Relative Luminous Intensity vs. Forward Current: This curve shows how light output increases with forward current. It is typically non-linear, emphasizing the importance of current regulation over voltage regulation for controlling brightness.
• Relative Luminous Intensity vs. Ambient Temperature: This graph demonstrates the thermal quenching effect, where luminous output decreases as the ambient temperature rises. Designers must account for this derating in high-temperature environments.
• Forward Voltage vs. Forward Current: This IV characteristic curve is crucial for designing the current-limiting circuitry. It shows the exponential relationship, highlighting the need for a series resistor to stabilize the operating point.
• Spectral Distribution: The curve depicts the relative radiant power versus wavelength, centered around the 632nm peak with a 20nm half-width, confirming the monochromatic red output.

5. Mechanical & Package Information

The LED is housed in a standard through-hole package. Key dimensional notes include:

• All dimensions are provided in millimeters, with tolerances of ±0.25mm unless otherwise specified.
• The maximum protrusion of resin under the flange is 1.0mm.
• Lead spacing is measured at the point where the leads emerge from the package body.
• The package drawing provides detailed measurements for the lens diameter, body height, lead length, and lead diameter, ensuring compatibility with PCB layout and panel cutouts.

The anode (positive) and cathode (negative) leads are typically differentiated by length or a flat spot on the cathode side of the flange, which is a common industry practice for polarity identification.

6. Soldering & Assembly Guidelines

6.1 Storage & Handling

LEDs should be stored in an environment not exceeding 30°C and 70% relative humidity. If removed from their original moisture-barrier packaging, they should be used within three months. For longer storage outside the original bag, use a sealed container with desiccant or a nitrogen-filled desiccator.

6.2 Cleaning

If cleaning is necessary, use alcohol-based solvents such as isopropyl alcohol. Avoid harsh or abrasive cleaners.

6.3 Lead Forming

Bend the leads at a point at least 3mm away from the base of the LED lens. Do not use the package body as a fulcrum. Lead forming must be performed at room temperature and before the soldering process. During PCB insertion, apply minimal clinching force to avoid mechanical stress on the epoxy lens or internal bonds.

6.4 Soldering Process

Maintain a minimum distance of 2mm between the base of the lens and the solder joint. Avoid immersing the lens in solder.

• Hand Soldering (Iron): Maximum temperature 350°C, maximum time 3 seconds per lead (one time only).
• Wave Soldering: Pre-heat to a maximum of 100°C for up to 60 seconds. Solder wave temperature should not exceed 260°C, with a maximum immersion time of 5 seconds. The LED should not be dipped lower than 2mm from the lens base.

Critical Note: Excessive temperature or time can deform the lens or cause catastrophic failure. Infrared (IR) reflow soldering is not suitable for this through-hole LED product.

7. Packaging & Ordering Information

The standard packaging configuration is as follows:

• Unit Pack: 1000, 500, 200, or 100 pieces per moisture-resistant packing bag.
• Inner Carton: Contains 8 packing bags, totaling 8,000 pieces.
• Outer Carton (Shipping Box): Contains 8 inner cartons, totaling 64,000 pieces.

In each shipping lot, only the final pack may contain a non-full quantity. The part number for this device is LTL763ENAK.

8. Application Recommendations

8.1 Typical Application Scenarios

This LED is well-suited for status indication in indoor and outdoor signs, as well as in general electronic equipment across the communications, computing, consumer, home appliance, and industrial sectors.

8.2 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness when connecting multiple LEDs in parallel, it is strongly recommended to use a individual current-limiting resistor in series with each LED (Circuit Model A). Driving multiple LEDs in parallel directly from a voltage source without individual resistors (Circuit Model B) is discouraged, as slight variations in the forward voltage (VF) characteristics of each LED will cause significant differences in current distribution and, consequently, uneven brightness.

8.3 Electrostatic Discharge (ESD) Protection

This LED is susceptible to damage from electrostatic discharge or power surges. Preventive measures are essential:

• Personnel should wear conductive wrist straps or anti-static gloves when handling LEDs.
• All equipment, workstations, and storage racks must be properly grounded.
• Use ionizers to neutralize static charge that may accumulate on the plastic lens due to friction during handling.
• Implement and monitor ESD training and certification programs for all personnel in static-safe areas.

9. Technical Comparison & Design Considerations

Compared to standard indicator LEDs, this device offers a significantly higher luminous intensity, making it visible in brightly lit environments. The 110-degree viewing angle provides a wide, diffuse illumination pattern ideal for panel indicators. The use of a red chip with a water-clear lens, as opposed to a tinted or diffused lens, maximizes light output efficiency. Designers must carefully consider heat dissipation, as the maximum power dissipation is 50mW, and performance degrades with increasing ambient temperature, as indicated by the derating curve. The forward voltage specification is critical for calculating the appropriate series resistor value when operating from a common voltage rail like 5V or 12V.

10. Frequently Asked Questions (FAQs)

Q: Can I drive this LED directly from a 5V microcontroller pin?
A: No. The typical forward voltage is 2.5V. Connecting it directly to 5V would cause excessive current flow, destroying the LED. You must use a series current-limiting resistor. For example, with a 5V supply and a target current of 20mA, the resistor value would be approximately (5V - 2.5V) / 0.02A = 125 Ohms. A standard 120 or 150 Ohm resistor would be suitable.

Q: What is the difference between Peak Wavelength and Dominant Wavelength?
A: Peak Wavelength (λp=632nm) is the wavelength at which the spectral output is physically the strongest. Dominant Wavelength (λd=624nm) is a calculated value based on human color perception (CIE diagram) that best represents the color we actually see. Dominant wavelength is more relevant for color specification in indicator applications.

Q: Why is a binning system used?
A> Due to manufacturing variations, LEDs from the same production batch can have different brightness levels. Binning sorts them into groups (M, N, P, Q) with defined intensity ranges. This allows manufacturers to offer consistent products and enables designers to select the appropriate brightness grade for cost and performance optimization, ensuring visual consistency in their end products.

Q: Can I use reflow soldering for this LED?
A: No. The datasheet explicitly states that IR reflow is not a suitable process for this through-hole type LED lamp. The recommended methods are hand soldering or wave soldering with the specified temperature and time constraints to prevent thermal damage to the epoxy lens.

11. Practical Design Case Study

Consider designing a control panel with ten status indicators. To ensure uniform brightness, specify LEDs from the same intensity bin (e.g., Bin N: 620-900mcd). Calculate the series resistor for a 12V supply: R = (12V - 2.5V) / 0.02A = 475 Ohms. A standard 470 Ohm, 1/4W resistor would be appropriate, as the power dissipation in the resistor is (12V-2.5V)*0.02A = 0.19W. On the PCB layout, ensure the holes for the LED leads are spaced according to the datasheet dimensions. Place a silkscreen outline to guide assembly. During wave soldering, use a fixture or tape to ensure the LEDs are not inserted deeper than 2mm from the lens base into the board, protecting them from excessive heat.

12. Operating Principle

This device is a light-emitting diode (LED). It operates on the principle of electroluminescence in a semiconductor material. When a forward voltage is applied across the p-n junction, electrons and holes recombine, releasing energy in the form of photons (light). The specific semiconductor materials used (e.g., Aluminum Gallium Arsenide - AlGaAs for red) determine the wavelength, and thus the color, of the emitted light. The water-clear epoxy lens serves to protect the semiconductor chip, shape the beam pattern to a 110-degree viewing angle, and enhance light extraction from the chip.

13. Technology Trends

While surface-mount device (SMD) LEDs dominate modern high-density electronics, through-hole LEDs remain relevant for applications requiring high reliability, ease of manual assembly, repair, and visibility from multiple angles. Trends in this segment focus on increasing luminous efficacy (more light output per unit of electrical power), improving color consistency through tighter binning, and enhancing long-term reliability under various environmental stresses. The drive towards higher efficiency aligns with broader energy-saving initiatives across the electronics industry.