LTL-R42FTGSH106PT LED Lamp Datasheet - Through Hole - Green/Yellow - 20mA - English Technical Document

1. Product Overview

This document details the specifications for a through-hole mounted LED lamp assembly, designed as a Circuit Board Indicator (CBI). The product consists of a black plastic right-angle housing (holder) that integrates with discrete LED lamps. It is engineered for straightforward assembly onto printed circuit boards (PCBs). The assembly is available in a tape and reel packaging format suitable for automated placement processes.

1.1 Core Advantages

• Ease of Assembly: The design facilitates simple and efficient mounting onto circuit boards.
• Enhanced Contrast: The black housing material improves the visual contrast ratio of the illuminated indicator.
• Energy Efficiency: Features low power consumption and high luminous efficiency.
• Environmental Compliance: This is a lead-free product compliant with RoHS directives.
• Color Options: Integrates T-1 sized LED lamps: one with an InGaN chip for green emission (525nm) and one with an AlInGaP chip for yellow emission (589nm). Both feature diffused lenses matching their respective colors.
• Packaging: Supplied in tape and reel format for automated handling.

1.2 Target Applications

This component is suitable for a variety of electronic equipment requiring status or indicator lights, including but not limited to:

• Communication devices
• Computer and peripheral equipment
• Consumer electronics
• Industrial control systems

2. Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The following ratings must not be exceeded under any conditions, as doing so may cause permanent damage to the device. All values are specified at an ambient temperature (TA) of 25°C.

2.2 Electrical and Optical Characteristics

These are the typical performance parameters measured at TA=25°C and a forward current (IF) of 10mA, unless otherwise noted.

Notes on Characteristics:

• Luminous intensity is measured with a sensor/filter approximating the CIE photopic eye-response curve.
• Viewing angle (θ1/2) is the off-axis angle where intensity drops to half its axial value.
• Dominant wavelength (λd) is derived from the CIE chromaticity diagram and defines the perceived color.
• The device is not designed for operation under reverse bias; the reverse current (IR) test condition is for characterization only.

3. Binning System Specification

The LEDs are sorted (binned) according to luminous intensity and dominant wavelength to ensure consistency within an application.

3.1 Green LED Binning

Luminous Intensity (@10mA):

Tolerance on each bin limit is ±15%.

Dominant Wavelength (@10mA):

Tolerance on each bin limit is ±1nm.

3.2 Yellow LED Binning

Luminous Intensity (@10mA):

Tolerance on each bin limit is ±15%.

Dominant Wavelength (@10mA):

Tolerance on each bin limit is ±1nm.

4. Mechanical and Packaging Information

4.1 Outline and Dimensions

The device uses a black plastic right-angle housing. Critical dimensional notes include:

• All dimensions are in millimeters (inches provided in the original drawing).
• General tolerance is ±0.25mm (±0.010") unless otherwise specified.
• The housing material is black plastic.
• LED1 is green (525nm) with a green diffused lens; LED2 is yellow (589nm) with a yellow diffused lens.

4.2 Packaging Specification

The product is supplied in tape and reel packaging for automated assembly.

• Carrier Tape: Made of black conductive polystyrene alloy, 0.50mm ±0.06mm thick.
• Pitch Tolerance: 10 sprocket hole pitch cumulative tolerance is ±0.20mm.
• Reel Quantity: Each 13-inch reel contains 350 pieces.

5. Performance Curve Analysis

The datasheet references typical performance curves which illustrate the relationship between key parameters. While the specific graphs are not reproduced in text, they typically include:

• I-V (Current-Voltage) Curves: Showing the forward voltage (VF) as a function of forward current (IF) for both green and yellow LEDs. This is crucial for designing the current-limiting circuitry.
• Luminous Intensity vs. Forward Current: Depicting how light output scales with drive current, highlighting the non-linear relationship and helping to optimize drive conditions for desired brightness.
• Relative Luminous Intensity vs. Ambient Temperature: Illustrating the decrease in light output as junction temperature rises, which is vital for thermal management in high-temperature or high-current applications.
• Spectral Distribution: Showing the relative radiant power versus wavelength, confirming the peak (λP) and spectral width (Δλ) for each color.

These curves are essential for designers to predict real-world performance beyond the single-point data provided in the tables.

6. Soldering and Assembly Guidelines

6.1 Storage and Handling

• Storage: LEDs should be stored in an environment not exceeding 30°C and 70% relative humidity. If removed from the original sealed packaging, they should be used within three months. For longer storage outside the original pack, use a sealed container with desiccant or a nitrogen ambient.
• Cleaning: If necessary, clean using alcohol-based solvents like isopropyl alcohol.

6.2 Lead Forming and PCB Mounting

• Bend leads at a point at least 3mm from the base of the LED lens. Do not use the lead frame base as a fulcrum.
• Lead forming must be performed at room temperature and before soldering.
• During PCB insertion, apply the minimum clinch force necessary to avoid imposing excessive mechanical stress on the component.

6.3 Soldering Process

A minimum clearance of 2mm must be maintained between the base of the lens/housing and the solder point. Avoid dipping the lens/housing into solder.

Recommended Soldering Conditions:

Warning: Excessive soldering temperature or time can cause lens deformation or catastrophic LED failure. Do not apply stress to the leads while the LED is hot from soldering.

7. Drive Circuit Design

LEDs are current-operated devices. Their forward voltage (VF) has a tolerance and varies with temperature. To ensure uniform brightness when driving multiple LEDs, especially in parallel, a series current-limiting resistor for each LED is strongly recommended.

• Recommended Circuit (A): Each LED has its own series resistor connected to the voltage supply. This compensates for variations in individual LED VF, ensuring each receives nearly the same current and thus has uniform brightness.
• Non-Recommended Circuit (B): Multiple LEDs connected directly in parallel with a single shared resistor. Differences in the I-V characteristics of each LED will cause current hogging, leading to significant brightness differences and potential over-stress of one LED.

The value of the series resistor (R) is calculated using Ohm's Law: R = (V_supply - VF_LED) / I_desired, where I_desired should not exceed the maximum DC forward current of 20mA.

8. Application Notes and Cautions

8.1 Suitable Applications

This LED lamp is suitable for general indicator use in indoor and outdoor signage, as well as in standard electronic equipment across the communication, computer, consumer, and industrial sectors as listed.

8.2 Design Considerations

• Thermal Management: While power dissipation is low, ensure the operating ambient temperature does not exceed 85°C. In enclosed spaces or high ambient temperatures, consider the derating of luminous intensity.
• Current Control: Always use a constant-current drive method or a voltage source with a series resistor. Never connect directly to a voltage source without current limiting.
• ESD Precautions: Although not explicitly stated, standard ESD handling procedures should be observed during assembly to prevent damage to the semiconductor dice.
• Optical Design: The 100-degree viewing angle and diffused lens provide a wide, soft illumination pattern suitable for panel indicators. For focused or narrow-beam applications, a different lens type would be required.

9. Technical Comparison and Positioning

This product represents a classic through-hole indicator solution. Its key differentiators include:

• Integrated Housing: The pre-assembled black right-angle holder simplifies board design and assembly compared to using discrete LEDs and separate mounts, while improving contrast.
• Dual Color in One Package: Combining green and yellow indicators in a single, compact through-hole package can save board space compared to using two separate single-color LEDs.
• Material Compliance: As a lead-free and RoHS compliant component, it meets modern environmental regulations for electronic manufacturing.
• Automation-Friendly: Tape and reel packaging supports high-volume, automated assembly processes, reducing labor costs.

Compared to surface-mount device (SMD) LEDs, through-hole versions like this one offer advantages in prototyping, manual assembly, and applications requiring higher mechanical bond strength or through-board light piping. However, SMD LEDs generally allow for higher density placement and are more suitable for fully automated, high-speed pick-and-place assembly lines.

10. Frequently Asked Questions (FAQs)

Q1: Can I drive this LED at its peak current of 60mA continuously?
A1: No. The Peak Forward Current rating (60mA) is only for very short pulses (≤0.1ms) at a low duty cycle (≤10%). The maximum continuous DC forward current is 20mA. Exceeding this can cause overheating and rapid degradation or failure.

Q2: Why is there a significant difference in typical luminous intensity between the green (420mcd) and yellow (11mcd) LEDs at the same 10mA current?
A2: This is primarily due to the different semiconductor materials (InGaN for green vs. AlInGaP for yellow) and the human eye's photopic sensitivity (CIE curve), which peaks in the green region (~555nm). The eye is less sensitive to the yellow wavelength emitted, resulting in a lower measured luminous intensity (in mcd) for the same radiant power.

Q3: What happens if I solder the LED without maintaining the 2mm clearance from the lens base?
A3: Applying heat too close to the plastic lens or housing can cause melting, deformation, or discoloration. It can also transfer excessive heat to the LED chip via the leads, potentially damaging the semiconductor junction or the internal wire bonds.

Q4: How do I interpret the bin codes when ordering?
A4: The bin codes (e.g., KL & G10 for green) define the guaranteed range of luminous intensity and dominant wavelength for the LEDs you will receive. Specifying bins allows you to select LEDs with consistent performance for your application. If color or brightness uniformity is critical, you should specify tight bins and potentially request testing data.

Q5: Is a reverse protection diode necessary in my circuit?
A5: The datasheet states the device is not designed for reverse operation and specifies a reverse current (IR) under a 5V test. While a small, occasional reverse voltage might not cause immediate failure, it is not recommended. In circuits where reverse voltage is possible (e.g., AC coupling, inductive loads), external protection such as a series diode or a reverse-biased diode across the LED is advisable to prevent applying reverse bias to the LED.