Bicolor LED Lamp Technical Datasheet - Through-Hole - Yellow/Green - 590nm/525nm - 20mA - 52mW/76mW

1. Product Overview

This document details the specifications for a bicolor through-hole LED lamp. The device is designed as a Circuit Board Indicator (CBI), housed in a black plastic right-angle holder for easy PCB assembly. It integrates two distinct LED chips within a single T-1 style package featuring a white diffused lens.

1.1 Core Features

• Dual-Color Source: Combines an AlInGaP chip for yellow emission (590nm) and an InGaN chip for green emission (525nm).
• Enhanced Contrast: The black housing material improves the visual contrast ratio of the illuminated indicator.
• Efficient Design: Characterized by low power consumption and high luminous efficiency.
• Environmental Compliance: This is a lead-free product compliant with RoHS directives.
• Versatile Mounting: The right-angle holder is stackable and facilitates straightforward assembly onto printed circuit boards.

1.2 Target Applications

This LED lamp is suitable for a broad range of electronic equipment requiring status or indicator functions. Primary application areas include computer systems, communication devices, consumer electronics, and industrial equipment.

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 (PD): Yellow: 52 mW max; Green: 76 mW max. This parameter defines the maximum power the LED can safely dissipate as heat.
• Forward Current: Continuous DC forward current is rated at 20 mA for both colors. A peak forward current of 60 mA is permissible under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10µs).
• Temperature Ranges: Operating: -30°C to +85°C; Storage: -40°C to +100°C.
• Soldering Temperature: Leads can withstand 260°C for a maximum of 5 seconds, measured 2.0mm from the LED body.

2.2 Electrical & Optical Characteristics

Typical performance is measured at TA=25°C with a forward current (IF) of 10mA, unless otherwise stated.

• Luminous Intensity (Iv): A key performance metric. Yellow: 85 mcd (typ), range 38-180 mcd. Green: 240 mcd (typ), range 110-520 mcd. Note that testing includes a ±30% tolerance.
• Viewing Angle (2θ1/2): Approximately 140 degrees for both colors, indicating a wide, diffuse light pattern suitable for indicator use.
• Wavelength: Yellow Peak (λP): 590 nm; Dominant (λd): 585-595 nm. Green Peak (λP): 517 nm; Dominant (λd): 520-532 nm. Spectral half-width (Δλ) is 20 nm for yellow and 35 nm for green.
• Forward Voltage (VF): Yellow: 2.1V (typ), range 1.6-2.6V. Green: 3.2V (typ), range 2.4-3.4V. The difference is due to the semiconductor materials used.
• Reverse Current (IR): Maximum 10 µA at a reverse voltage (VR) of 5V. The device is not designed for reverse-bias operation.

3. Binning System Explanation

The LEDs are sorted (binned) based on key optical parameters to ensure consistency within a production batch. The bin tables provide reference ranges.

3.1 Luminous Intensity Binning

Separate bin codes are used for yellow and green LEDs based on their measured luminous intensity at 10mA.

• Yellow Bins: BC (38-65 mcd), DE (65-110 mcd), FG (110-180 mcd).
• Green Bins: FG (110-180 mcd), HJ (180-310 mcd), KL (310-520 mcd).
• Tolerance for each bin limit is ±15%.

3.2 Dominant Wavelength Binning

LEDs are also binned by their dominant wavelength to control color consistency.

• Yellow Wavelength Bins: Code 1 (585-590 nm), Code 2 (590-595 nm).
• Green Wavelength Bins: Code G10 (520-526 nm), Code G11 (526-532 nm).
• Tolerance for each bin limit is ±2 nm.

4. Performance Curve Analysis

The datasheet references typical characteristic curves which are essential for design. While specific graphs are not reproduced here, they typically include:

• Relative Luminous Intensity vs. Forward Current: Shows how light output increases with current, typically in a near-linear relationship before efficiency droop.
• Forward Voltage vs. Forward Current: Illustrates the diode's I-V characteristic, crucial for designing current-limiting circuits.
• Relative Luminous Intensity vs. Ambient Temperature: Demonstrates the negative temperature coefficient of light output; intensity decreases as junction temperature rises.
• Spectral Distribution: Graphs showing the relative radiant power versus wavelength, highlighting the peak and dominant wavelengths.

5. Mechanical & Packaging Information

5.1 Outline Dimensions

The device uses a standard T-1 (3mm) lamp form factor mounted in a black plastic right-angle holder. Critical dimensional notes include:

• All dimensions are in millimeters (with inch equivalents).
• Standard tolerance is ±0.25mm unless specified otherwise.
• The housing is made of black plastic.
• The unit contains three LED positions (LED1~3), each with a bicolor yellow/green chip and white diffused lens.

5.2 Polarity Identification

For through-hole LEDs, the cathode is typically identified by a flat spot on the lens, a shorter lead, or other marking on the holder. The specific identification method should be verified from the dimensional drawing.

6. Soldering & 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, use a sealed container with desiccant or a nitrogen ambient.

6.2 Lead Forming

If leads need to be bent, do so before soldering and at normal temperature. The bend must be at least 3mm from the base of the LED lens. Do not use the LED body as a fulcrum. Apply minimal force during PCB insertion to avoid stress.

6.3 Soldering Process

Critical Rule: Maintain a minimum clearance of 2mm from the base of the lens/holder to the solder point. Never immerse the lens/holder in solder.

• Hand Soldering (Iron): Max temperature 350°C, max time 3 seconds per lead (one time only).
• Wave Soldering: Pre-heat to max 120°C for up to 100 seconds. Solder wave at max 260°C for up to 5 seconds. Ensure the PCB is designed so the solder wave does not come within 2mm of the lens base.
• Not Recommended: IR reflow soldering is not suitable for this through-hole type product.

Warning: Excessive temperature or time can deform the lens or cause catastrophic LED failure.

6.4 Cleaning

If cleaning is necessary, use alcohol-based solvents like isopropyl alcohol.

7. Packaging & Ordering Information

The packing specification details how the LEDs are supplied, typically in tape-and-reel format for automated assembly or in bulk tubes. The specific reel dimensions, pocket spacing, and orientation are defined in the associated packing diagram. The part number LTL14FTGSGAJ3H273Y encodes specific attributes like color, intensity bin, and wavelength bin.

8. Application Recommendations

8.1 Typical Application Scenarios

This LED is well-suited for status indicators, power-on lights, and signalization in various electronic devices for indoor, outdoor signage, and general electronic equipment.

8.2 Drive Circuit Design

LEDs are current-driven devices. To ensure uniform brightness when driving multiple LEDs, especially 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 (Circuit Model B) is discouraged, as small variances in forward voltage (VF) will cause significant differences in current and, consequently, brightness.

8.3 Electrostatic Discharge (ESD) Protection

The LED is susceptible to damage from electrostatic discharge or power surges. Standard ESD handling precautions must be observed during assembly and handling, including the use of grounded workstations and wrist straps.

9. Technical Comparison & Differentiation

This product's primary differentiation lies in its integrated bicolor capability within a single, easy-to-assemble through-hole package. Compared to using two separate single-color LEDs, it saves PCB space and simplifies assembly. The wide viewing angle and diffused lens provide omnidirectional visibility. The specific binning system allows designers to select parts tailored to their required brightness and color point, enabling better consistency in end products.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED at its maximum DC current of 20mA continuously?

A: Yes, but you must ensure the power dissipation (VF * IF) does not exceed the rated 52 mW (Yellow) or 76 mW (Green) and that the ambient temperature is within the operating range. Adequate PCB layout for heat dissipation is recommended for continuous operation at max current.

Q: Why is the typical forward voltage different for the yellow and green chips?

A: The difference stems from the bandgap energy of the semiconductor materials. AlInGaP (yellow) has a lower bandgap than InGaN (green), resulting in a lower forward voltage for the same current.

Q: What does the \"±30% testing tolerance\" on luminous intensity mean?

A: It means the measured Iv value used to verify the specification has an inherent instrument tolerance of ±30%. The actual LED output is within the Min-Max range stated in the table, and the test equipment's accuracy accounts for this additional tolerance band.

Q: Is a heat sink required?

A: For typical indicator use at 10-20mA, a dedicated heat sink is not necessary. The power dissipation is low, and the leads provide sufficient thermal path to the PCB. For maximum reliability at absolute maximum ratings, consider the PCB copper area as a heat spreader.

11. Practical Design & Usage Case

Scenario: Designing a multi-status indicator panel for a network router with Power (Green), Activity (Flashing Green), and Fault (Yellow) indicators using a single component type.

Implementation: Use three of these bicolor LEDs. Drive the green chip of each LED for Power and Activity states. Drive the yellow chip of the third LED for the Fault state. By using a common component, inventory is simplified. The wide viewing angle ensures visibility from various angles. The designer would select appropriate intensity bins (e.g., KL bin for green, FG for yellow) based on the required brightness and use individual series resistors for each LED chip being driven to ensure consistent current and brightness across all units.

12. Operating Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor p-n junction devices that emit light through electroluminescence. When a forward voltage is applied, electrons and holes recombine in the active region, releasing energy in the form of photons. The color (wavelength) of the emitted light is determined by the bandgap energy of the semiconductor material. This device contains two independent semiconductor chips: one made of AlInGaP for yellow light and one made of InGaN for green light, housed together. Applying current to the respective anode/cathode pairs activates one color at a time.

13. Technology Trends

The general trend in indicator LEDs continues toward higher efficiency, lower power consumption, and broader color gamuts. While through-hole packages remain relevant for certain applications requiring manual assembly or high reliability in harsh environments, the overall industry shift is towards surface-mount device (SMD) packages for automated assembly, miniaturization, and better thermal management. Advancements in phosphor technology and chip design also allow for more saturated colors and tighter color consistency (smaller binning ranges) in modern LED products.