LTL1DETBYJR5 LED Lamp Datasheet - T-1 Package - Blue/Yellow - 20mA - 3.8V - English Technical Document

1. Product Overview

The LTL1DETBYJR5 is a through-hole LED lamp designed for status indication and signaling applications. It is offered in a standard T-1 type package, providing a reliable and cost-effective solution for a wide range of electronic devices.

1.1 Core Features and Advantages

This LED product is characterized by its low power consumption and high efficiency, making it suitable for energy-sensitive designs. It is compliant with RoHS (Restriction of Hazardous Substances) directives, being lead-free. Furthermore, it is classified as a halogen-free product, with chlorine (Cl) and bromine (Br) content strictly controlled below 900 ppm each, and their combined total below 1500 ppm. The device utilizes InGaN technology for the Blue chip and AlInGaP technology for the Yellow chip, both encapsulated within a white diffused lens that provides a uniform light appearance.

1.2 Target Applications and Markets

The primary application areas for this LED include communication equipment, computer peripherals, consumer electronics, and home appliances. Its versatility and standard form factor make it a common choice for power indicators, status lights, and backlighting in various electronic products.

2. Technical Parameters: In-Depth Objective Interpretation

2.1 Absolute Maximum Ratings

All ratings are specified at an ambient temperature (TA) of 25°C. Exceeding these limits may cause permanent damage.

• Power Dissipation: Yellow: 78 mW max; Blue: 120 mW max. This parameter defines the maximum power the LED can dissipate as heat.
• Peak Forward Current: 90 mA for both colors, but only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10 µs).
• DC Forward Current: The recommended continuous forward current for reliable operation is 30 mA for both Yellow and Blue LEDs.
• Temperature Ranges: Operating: -40°C to +85°C; Storage: -40°C to +100°C.
• Lead Soldering Temperature: 260°C maximum for 5 seconds, measured 2.0mm from the LED body.

2.2 Electrical and Optical Characteristics

Key performance parameters are measured at TA=25°C and IF=20 mA, unless otherwise stated.

• Luminous Intensity (Iv): Yellow: 140 mcd min, 680 mcd typ; Blue: 110 mcd min, 880 mcd typ. The testing tolerance for Iv is ±30%.
• Viewing Angle (2θ1/2): Approximately 40 degrees for both colors, defined as the off-axis angle where intensity drops to half its axial value.
• Wavelength:
  • Yellow: Peak Wavelength (λP) ~595 nm; Dominant Wavelength (λd) 580-604 nm.
  • Blue: Peak Wavelength (λP) ~468 nm; Dominant Wavelength (λd) 462-478 nm.
• Spectral Line Half-Width (Δλ): Yellow: ~16 nm; Blue: ~35 nm. This indicates the spectral purity of the emitted light.
• Forward Voltage (VF): Yellow: 2.05-2.4 V typ; Blue: 3.1-3.8 V typ. The higher VF for Blue is typical for InGaN-based LEDs.
• Reverse Current (IR): 10 µA maximum at VR=5V. The device is not designed for reverse bias operation.

3. Binning System Specification

The LEDs are sorted into bins based on their luminous intensity at 20 mA. This ensures consistency in brightness for production applications. The bin limits have a tolerance of ±30%.

• Blue LED Bins: FG (110-180 mcd), HJ (180-310 mcd), KL (310-520 mcd), MN (520-880 mcd).
• Yellow LED Bins: GH (140-240 mcd), JK (240-400 mcd), LM (400-680 mcd).

Designers should specify the required bin code to guarantee the desired brightness level in their application.

4. Performance Curve Analysis

While specific graphs are referenced in the datasheet (Typical Electrical/Optical Characteristics Curves), the following trends are standard for such LEDs and can be inferred from the provided data:

4.1 Current vs. Voltage (I-V) Characteristic

The forward voltage (VF) increases with forward current (IF). The Blue LED, with its higher bandgap, exhibits a higher turn-on and operating voltage (~3.1-3.8V) compared to the Yellow LED (~2.05-2.4V).

4.2 Luminous Intensity vs. Current (L-I)

Luminous intensity is approximately proportional to the forward current up to the maximum rated current. Operating above 20mA will increase brightness but also power dissipation and junction temperature, which can affect longevity and wavelength.

4.3 Temperature Dependence

LED performance is temperature-sensitive. Typically, luminous intensity decreases as the junction temperature increases. The forward voltage also decreases slightly with rising temperature. The specified operating range of -40°C to +85°C defines the ambient conditions under which the published characteristics are guaranteed.

5. Mechanical and Package Information

5.1 Outline Dimensions

The LED uses a standard T-1 (3mm) radial leaded package. Key dimensional notes include:

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

5.2 Polarity Identification

For radial LEDs, the longer lead typically denotes the anode (positive), and the shorter lead denotes the cathode (negative). The flat side on the lens flange may also indicate the cathode side. Always verify polarity before soldering to prevent reverse bias damage.

6. Soldering and Assembly Guidelines

6.1 Storage Conditions

For optimal shelf life, store LEDs in an environment not exceeding 30°C and 70% relative humidity. If removed from the original moisture-barrier bag, use within three months. For longer storage outside the original packaging, use a sealed container with desiccant or a nitrogen atmosphere.

6.2 Cleaning

If cleaning is necessary, use alcohol-based solvents like isopropyl alcohol. Avoid harsh chemicals that may damage the epoxy lens.

6.3 Lead Forming

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

6.4 Soldering Process

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

• Hand Soldering (Iron): Max temperature 350°C, max time 3 seconds per lead (one time only).
• Wave Soldering: Pre-heat ≤100°C for ≤60 sec. Solder wave ≤260°C for ≤5 sec. Ensure the dipping position is no lower than 2mm from the lens base.
• Important: Infrared (IR) reflow soldering is NOT suitable for this through-hole type LED product. Excessive heat or time can deform the lens or cause catastrophic failure.

7. Packaging and Ordering Information

7.1 Packaging Specification

The LEDs are packed in anti-static bags. The standard packing configuration is:

• 500, 200, or 100 pieces per packing bag.
• 10 packing bags per inner carton (total 5,000 pcs).
• 8 inner cartons per outer carton (total 40,000 pcs).
• The last pack in a shipping lot may not be a full pack.

8. Application Suggestions and Design Considerations

8.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness, especially when connecting multiple LEDs in parallel, it is strongly recommended to use a current-limiting resistor in series with each LED (Circuit A). Driving multiple LEDs in parallel without individual resistors (Circuit B) is not recommended due to variations in the forward voltage (VF) of individual LEDs, which will cause uneven current distribution and differing brightness levels.

8.2 Electrostatic Discharge (ESD) Protection

These LEDs are sensitive to electrostatic discharge. Implement the following ESD controls during handling and assembly:

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

8.3 Thermal Management

While the power dissipation is low, proper PCB layout can help dissipate heat. Avoid placing the LED near other heat-generating components. Operating the LED at currents below the maximum 30mA rating will improve long-term reliability by reducing junction temperature.

9. Technical Comparison and Differentiation

The LTL1DETBYJR5 offers a combination of features that position it for general-purpose indicator use:

• Halogen-Free Compliance: Meets stringent environmental requirements for chlorine and bromine content, which is advantageous for eco-friendly designs and certain market regulations.
• Wide Viewing Angle: The 40-degree viewing angle and white diffused lens provide a wide, uniform illumination pattern suitable for status indicators that need to be visible from various angles.
• Dual Color Option in Same Package: The availability of both Blue (InGaN) and Yellow (AlInGaP) in the identical T-1 package simplifies inventory and design for multi-color indication systems.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 Can I drive this LED directly from a 5V supply?

No. You must use a series current-limiting resistor. For example, for the Blue LED at 20mA with a typical VF of 3.8V from a 5V supply: R = (5V - 3.8V) / 0.020A = 60 Ohms. A standard 62-ohm resistor would be suitable. Always calculate based on the maximum VF to ensure current does not exceed limits.

10.2 Why is the luminous intensity specified with a ±30% tolerance?

This tolerance accounts for normal production variations in the semiconductor chip and the encapsulation process. The binning system is used to sort LEDs into tighter brightness groups to provide consistency for the end-user who specifies a particular bin code.

10.3 What is the difference between Peak Wavelength and Dominant Wavelength?

Peak Wavelength (λP) is the wavelength at which the emission spectrum has its maximum intensity. Dominant Wavelength (λd) is derived from the CIE chromaticity diagram and represents the single wavelength of the pure spectral color that matches the perceived color of the LED. λd is more relevant for color specification in human vision.

10.4 Can I use this LED for outdoor applications?

The datasheet states it is suitable for indoor and outdoor signs. However, for harsh outdoor environments with prolonged exposure to UV radiation, moisture, and extreme temperatures, the long-term reliability of the epoxy lens material should be evaluated. Conformal coating on the PCB may be necessary for additional protection.

11. Practical Application Example

Scenario: Designing a multi-status indicator panel for a network router with Power (Green), Activity (Yellow), and Link (Blue) LEDs, all powered from a 3.3V rail.

Design Steps:

1. Component Selection: Choose the LTL1DETBYJR5 in the Yellow and Blue variants (a separate Green LED model would be needed). Select appropriate bin codes for desired brightness consistency (e.g., JK for Yellow, HJ for Blue).
2. Current Setting: Decide on a drive current, e.g., 15 mA for adequate brightness and lower power consumption.
3. Resistor Calculation for Blue LED: Using max VF=3.8V, supply=3.3V. R = (3.3V - 3.8V) / 0.015A = Negative value. This indicates 3.3V is insufficient to forward bias the Blue LED at its typical voltage. The design must use a higher supply voltage (e.g., 5V) for the Blue LED or select a Blue LED with a lower VF.
4. Resistor Calculation for Yellow LED (if using 3.3V): Using max VF=2.4V. R = (3.3V - 2.4V) / 0.015A = 60 Ohms.
5. PCB Layout: Place LEDs on the front panel. Ensure holes for leads are sized correctly. Keep a 2mm clearance between the solder pad and the LED body. Route traces to supply and ground.
6. Assembly: Insert LEDs, bend leads on the solder side, and clip. Use a temperature-controlled soldering iron (max 350°C) to solder each lead quickly (<3 sec).

This example highlights the importance of checking supply voltage against LED forward voltage during the design phase.

12. Operating Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that emit light when an electric current passes through them. This phenomenon is called electroluminescence.

• Blue LED (InGaN): The active region is made of Indium Gallium Nitride (InGaN). When electrons and holes recombine in this region, energy is released as photons. The specific bandgap energy of the InGaN alloy determines the blue color (higher energy, shorter wavelength ~468 nm).
• Yellow LED (AlInGaP): The active region uses Aluminum Indium Gallium Phosphide (AlInGaP). This material system has a lower bandgap energy compared to InGaN, resulting in the emission of yellow light (lower energy, longer wavelength ~595 nm).
• White Diffused Lens: The epoxy lens serves two purposes: 1) It encapsulates and protects the semiconductor chip and wire bonds. 2) The white diffused material scatters the light from the small chip, creating a uniform, wide-angle emission pattern and giving the un-energized LED a white appearance.

13. Technology Trends and Developments

While through-hole LEDs like the T-1 package remain vital for prototyping, manual assembly, and certain applications, the broader industry trend has shifted significantly towards Surface-Mount Device (SMD) LEDs. SMD packages (e.g., 0603, 0805, 2835, 3535) offer advantages in automated assembly, smaller footprint, lower profile, and often better thermal management. For high-brightness and high-power applications, SMD packages and dedicated high-power LED packages (with metal-core PCBs) are dominant.

However, through-hole LEDs continue to be relevant due to their mechanical robustness, ease of hand-soldering, and suitability for educational kits, hobbyist projects, and applications where leads provide mechanical strain relief. Advances in materials have also improved the efficiency and lifetime of traditional through-hole packages. The focus for such components is often on achieving higher reliability, stricter environmental compliance (like halogen-free), and maintaining cost-effectiveness for high-volume, price-sensitive indicator applications.