Green Through-Hole LED Lamp LTL1CHJGTNN Datasheet - T-1 Package - 572nm - 20mA - English Technical Document

1. Product Overview

This document details the specifications for a high-efficiency green through-hole LED lamp. Designed for status indication and general illumination purposes, this component is suitable for a wide range of electronic applications. The device features a popular T-1 (3mm) diameter package with a green transparent lens, offering a distinct visual signal.

1.1 Key Features

• Low power consumption and high luminous efficiency.
• Constructed with lead-free materials and is fully compliant with RoHS environmental standards.
• Standard T-1 (3mm) diameter package for easy integration into existing designs.
• Utilizes AlInGaP technology to produce a green light with a dominant wavelength of 572nm.

1.2 Target Applications

This LED is versatile and finds use in multiple sectors, including communication equipment, computer peripherals, consumer electronics, home appliances, and industrial control systems. Its primary function is to provide clear and reliable status indication.

2. Technical Parameter Deep-Dive

This section provides a detailed, objective analysis of the LED's key performance parameters under standard test conditions (TA=25°C).

2.1 Absolute Maximum Ratings

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

• Power Dissipation (Pd): 75 mW maximum.
• DC Forward Current (IF): 30 mA continuous.
• Peak Forward Current: 60 mA (pulse width ≤10ms, duty cycle ≤1/10).
• Operating Temperature Range: -30°C to +85°C.
• 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.

2.2 Electrical & Optical Characteristics

The following parameters define the typical performance of the LED. All measurements are taken at IF = 20mA unless otherwise stated.

• Luminous Intensity (Iv): 110 mcd (Min), 310 mcd (Typ). This is the measure of perceived light power. The actual intensity for a specific unit is determined by its bin code (see Section 4). A ±15% testing tolerance is applied to guaranteed values.
• Viewing Angle (2θ1/2): 45 degrees (Typ). This is the full angle at which the luminous intensity drops to half of its axial (on-center) value, defining the beam spread.
• Peak Emission Wavelength (λP): 575 nm (Typ). The wavelength at which the spectral power distribution is maximum.
• Dominant Wavelength (λd): 572 nm (Typ). This is the single wavelength that best represents the perceived color of the LED, derived from the CIE chromaticity diagram.
• Spectral Line Half-Width (Δλ): 11 nm (Typ). The width of the emission spectrum at half its maximum power, indicating color purity.
• Forward Voltage (VF): 2.1V (Min), 2.4V (Typ) at 20mA.
• Reverse Current (IR): 100 μA (Max) at VR = 5V. Important: This device is not designed for reverse-bias operation; this test condition is for characterization only.

3. Binning System Specification

To ensure consistency in production, LEDs are sorted into bins based on key performance metrics. The part number LTL1CHJGTNN includes bin codes for intensity and wavelength.

3.1 Luminous Intensity Binning

Units are measured in millicandelas (mcd) at IF=20mA. The part number suffix \"HJ\" corresponds to the following bin:

• Bin Code HJ0: Minimum 180 mcd, Maximum 310 mcd. Tolerance on bin limits is ±15%.

3.2 Dominant Wavelength Binning

Units are in nanometers (nm) at IF=20mA. The part number suffix \"GT\" (implied by the 572nm typical) would fall within a range like:

• Example Bin H09: Minimum 572.0 nm, Maximum 574.0 nm. Tolerance on bin limits is ±1nm.

4. Performance Curve Analysis

While specific graphical data is referenced in the datasheet, typical curves for this type of LED would illustrate the following relationships, crucial for design:

• Relative Luminous Intensity vs. Forward Current: Shows how light output increases with current, typically in a near-linear relationship before saturation.
• Forward Voltage vs. Forward Current: Demonstrates the diode's I-V characteristic, essential for calculating the correct series current-limiting resistor.
• Relative Luminous Intensity vs. Ambient Temperature: Illustrates the decrease in light output as junction temperature rises, highlighting the importance of thermal management.
• Spectral Distribution: A plot showing the intensity of light emitted across different wavelengths, centered around 575nm with an 11nm half-width.

5. Mechanical & Package Information

5.1 Outline Dimensions

The LED uses a standard radial leaded package.

• Package Type: T-1 (3mm diameter round).
• Lead Diameter: 0.6mm (typical).
• Lead Spacing: Measured where leads emerge from the package body. Standard spacing is 2.54mm (0.1\").
• Body Length: Approximately 5.0mm to 8.0mm (varies).
• Tolerances: ±0.25mm unless otherwise specified. Protruded resin under the flange is 1.0mm maximum.

5.2 Polarity Identification

The cathode (negative lead) is typically identified by a flat spot on the LED lens rim, a shorter lead, or a notch on the flange. The anode (positive lead) is longer in most standard packages. Always verify polarity before installation to prevent damage.

6. Soldering & Assembly Guidelines

Proper handling is critical to ensure reliability and prevent damage to the LED epoxy lens or internal die.

6.1 Storage Conditions

For long-term storage, maintain an environment not exceeding 30°C and 70% relative humidity. LEDs removed from their original moisture-barrier bags should be used within three months. For extended storage, use sealed containers with desiccant or a nitrogen atmosphere.

6.2 Lead Forming

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

6.3 Soldering Process

Critical Rule: Maintain a minimum distance of 2mm from the base of the epoxy lens to the solder point. Do not immerse the lens in solder.

• Hand Soldering (Iron): Maximum temperature 350°C. Maximum soldering time 3 seconds per lead. Do not rework.
• Wave Soldering: Pre-heat to a maximum of 100°C for up to 60 seconds. Solder wave temperature maximum 260°C. Contact time maximum 5 seconds. Ensure the LED is positioned so the solder wave does not come within 2mm of the lens base.
• Not Recommended: Infrared (IR) reflow soldering is not suitable for this through-hole package type.

6.4 Cleaning

If necessary, clean only with alcohol-based solvents such as isopropyl alcohol. Avoid aggressive or unknown chemical cleaners.

7. Packaging & Ordering Information

7.1 Packaging Specification

The LEDs are packed in anti-static bags.

• Bag Quantities: 1000, 500, 200, or 100 pieces per bag.
• Inner Carton: Contains 10 packing bags, totaling 10,000 pieces.
• Outer Carton (Shipping Lot): Contains 8 inner cartons, totaling 80,000 pieces. The final pack in a shipping lot may contain less than a full carton.

8. Application & Design Recommendations

8.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness, especially when connecting multiple LEDs in parallel, a series current-limiting resistor is mandatory for each LED.

• Recommended Circuit (A): Each LED has its own series resistor (R = (Vsupply - VF) / IF). This compensates for minor variations in the forward voltage (VF) of individual LEDs, ensuring equal current and thus equal brightness.
• Not Recommended Circuit (B): Connecting multiple LEDs in parallel with a single shared resistor. Small differences in VF will cause current hogging, leading to significant brightness mismatch and potential over-current in one LED.

8.2 Electrostatic Discharge (ESD) Protection

This LED is susceptible to damage from electrostatic discharge. Implement the following in the handling area:

• Use grounded wrist straps and anti-static gloves.
• Ensure all equipment, workbenches, and storage racks are properly grounded.
• Use ionizers to neutralize static charge that may build up on the plastic lens.
• Maintain training and certification programs for personnel working in ESD-protected areas.

8.3 Thermal Considerations

The maximum power dissipation is 75mW. The DC forward current derates linearly from 30mA at 30°C ambient. In high-temperature environments or high-current applications, ensure adequate airflow or consider reducing the drive current to maintain reliable operation and long lifetime.

9. Technical Comparison & Differentiation

Compared to older technology green LEDs (e.g., based on Gallium Phosphide), this AlInGaP (Aluminum Indium Gallium Phosphide) type offers significantly higher luminous efficiency, resulting in brighter output at the same current. The 572nm dominant wavelength provides a pure, saturated green color. The T-1 package ensures broad compatibility with existing PCB layouts and sockets designed for standard indicator lamps.

10. Frequently Asked Questions (FAQ)

10.1 What resistor value should I use with a 5V supply?

Using the typical VF of 2.4V and target IF of 20mA: R = (5V - 2.4V) / 0.02A = 130 Ohms. The nearest standard value is 130Ω or 150Ω. Always calculate power rating: P = I²R = (0.02)² * 130 = 0.052W. A standard 1/8W (0.125W) resistor is sufficient.

10.2 Can I drive this LED at 30mA continuously?

Yes, 30mA is the maximum continuous DC current rating at 25°C ambient. However, at this current, the power dissipation will be higher (approx. VF * IF = 2.4V * 0.03A = 72mW), which is very close to the absolute maximum of 75mW. For robust design and longer life, operating at 20mA is recommended, especially in warmer environments.

10.3 How do I identify the anode and cathode?

Look for the physical identifiers: the longer lead is typically the anode (+). Additionally, there is often a flat edge on the rim of the round lens or a notch on the plastic flange next to the cathode (-) lead.

11. Practical Design Case Study

Scenario: Designing a panel with four status indicators for a power supply unit, showing AC OK, DC OK, Fault, and Standby. The system logic operates at 3.3V.

Design Steps:

1. Current Selection: Choose 15mA per LED for good visibility and lower power consumption.
2. Resistor Calculation: R = (3.3V - 2.4V) / 0.015A = 60 Ohms. Use 62Ω standard resistors.
3. Circuit Layout: Implement Circuit A from the datasheet: four independent circuits, each with one LED and one 62Ω resistor connected to the 3.3V rail via a driver transistor or GPIO pin.
4. PCB Layout: Place holes with 2.54mm spacing. Ensure the solder pads are at least 2mm away from the LED body outline on the silkscreen. Group the LEDs for consistent appearance.
5. Assembly: Insert LEDs, bend leads slightly on the solder side to retain them, then wave solder using the specified profile, ensuring board orientation prevents solder wicking up the leads.

This approach guarantees uniform brightness and reliable long-term operation.

12. Technology Principle Introduction

This LED is based on AlInGaP semiconductor material grown on a substrate. When a forward voltage is applied across the p-n junction, electrons and holes are injected into the active region where they recombine. This recombination process releases energy in the form of photons (light). The specific composition of the AlInGaP layers determines the bandgap energy, which directly defines the wavelength (color) of the emitted light—in this case, green at 572nm. The transparent epoxy lens serves to protect the semiconductor die, shape the beam pattern (45-degree viewing angle), and enhance light extraction.

13. Industry Trends & Developments

The through-hole LED market continues to serve legacy designs and applications where robustness and ease of manual assembly are valued. However, the overall industry trend is strongly towards surface-mount device (SMD) packages (e.g., 0603, 0805, 3528) for automated assembly, higher density, and better thermal performance. Advancements in LED technology focus on increasing luminous efficacy (lumens per watt), improving color consistency through tighter binning, and expanding the range of available colors and color temperatures. For through-hole types, improvements often come in the form of higher brightness within the same package size and enhanced reliability under varying environmental conditions.