LTL30EKFGJ Through Hole LED Lamp Datasheet - T-1 3/4 Package - 2.4V - 30mA - Amber/Yellow Green - English Technical Document

1. Product Overview

This document details the specifications for the LTL30EKFGJ, a through-hole LED lamp designed for status indication and general illumination in a wide range of electronic applications. The device is offered in two distinct colors: Amber and Yellow Green, providing design flexibility for visual feedback systems. The LED features a popular T-1 3/4 (approximately 5mm) diameter package with a diffused white lens, ensuring a wide viewing angle and uniform light distribution.

The core advantages of this product include its low power consumption and high luminous efficiency, making it suitable for battery-powered or energy-conscious designs. It is constructed with lead-free materials and is fully compliant with RoHS (Restriction of Hazardous Substances) directives, aligning with modern environmental and regulatory standards. The through-hole design facilitates easy manual or automated assembly onto printed circuit boards (PCBs).

The target market encompasses a broad spectrum of the electronics industry, including communication equipment, computer peripherals, consumer electronics, and home appliances. Its primary function is to provide clear, reliable visual status indication for power, activity, or system state.

2. Technical Parameter Deep Dive

2.1 Absolute Maximum Ratings

Operating the device beyond these limits may cause permanent damage. The ratings are specified at an ambient temperature (TA) of 25°C.

• Power Dissipation: 80 mW (for both Amber and Yellow Green). This parameter defines the maximum amount of power the LED can safely dissipate as heat.
• Peak Forward Current: 90 mA (pulse condition: duty cycle ≤ 1/10, pulse width ≤ 10μs). This is the maximum instantaneous current for short pulses, useful for multiplexing or brief high-brightness flashes.
• DC Forward Current: 30 mA. This is the recommended maximum continuous forward current for reliable long-term operation.
• Operating Temperature Range: -40°C to +85°C. The device is rated for industrial-grade temperature resilience.
• 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

These parameters are measured at TA=25°C and a standard test current (IF) of 20mA, unless otherwise noted. They define the performance under normal operating conditions.

• Luminous Intensity (Iv):
  • Yellow Green: Typical 110 mcd, ranging from Min. 50 mcd to Max. 110 mcd.
  • Amber: Typical 240 mcd, ranging from Min. 110 mcd to Max. 240 mcd.
  • Note: The guarantee includes a ±30% testing tolerance. Measurement uses a sensor/filter approximating the CIE photopic eye-response curve.
• Viewing Angle (2θ1/2): Approximately 80 degrees for both colors. This is the full angle at which the luminous intensity drops to half of its axial (on-center) value, indicating a wide beam pattern.
• Peak Emission Wavelength (λP):
  • Yellow Green: 575 nm.
  • Amber: 611 nm.
• Dominant Wavelength (λd):
  • Yellow Green: 572 nm.
  • Amber: 605 nm.
  • Note: This is derived from the CIE chromaticity diagram and represents the perceived color.
• Spectral Line Half-Width (Δλ):
  • Yellow Green: 11 nm.
  • Amber: 17 nm. A wider half-width generally results in a less saturated, more "pastel" color appearance.
• Forward Voltage (VF):
  • Yellow Green: 2.1V (Typ.), 2.4V (Max.) at IF=20mA.
  • Amber: 2.1V (Typ.), 2.4V (Max.) at IF=20mA.
• Reverse Current (IR): 10 μA (Max.) at a Reverse Voltage (VR) of 5V. Critical Note: This device is not designed for reverse-bias operation; this test condition is for characterization only. Applying reverse voltage in-circuit can damage the LED.

3. Binning System Specification

To ensure consistency in brightness and color for production applications, the LEDs are sorted into bins. Designers should specify the required bin codes when ordering for critical color-matching applications.

3.1 Luminous Intensity Binning

LEDs are grouped based on their measured luminous intensity at 20mA.

• Yellow Green Bins: C (50-65 mcd), D (65-85 mcd), E (85-110 mcd), F (110-140 mcd). Tolerance per bin limit is ±15%.
• Amber Bins: F (110-140 mcd), G (140-180 mcd), H (180-240 mcd), J (240-310 mcd), K (310-400 mcd). Tolerance per bin limit is ±15%.

3.2 Dominant Wavelength Binning (Yellow Green Only)

For precise color control, Yellow Green LEDs are further binned by dominant wavelength.

• Hue Bin Codes: H06 (564.0 - 568.0 nm), H07 (568.0 - 572.0 nm), H08 (572.0 - 574.0 nm). Tolerance per bin limit is ±1 nm.

This binning allows designers to select LEDs that will appear identical in color across a product, which is crucial for multi-LED displays or indicators.

4. Performance Curve Analysis

While specific graphical curves are referenced in the datasheet (Fig.1, Fig.6), the typical relationships can be described:

• I-V (Current-Voltage) Curve: The forward voltage (VF) exhibits a logarithmic relationship with forward current (IF). At the recommended 20mA operating point, VF is typically 2.1V but can vary up to 2.4V. This variance underscores the need for current-limiting resistors, not voltage sources, to drive LEDs.
• Luminous Intensity vs. Current: Intensity is approximately proportional to forward current in the normal operating range (up to 30mA DC). Exceeding the maximum current leads to super-linear heat generation and rapid degradation of light output and lifespan.
• Temperature Characteristics: Luminous intensity typically decreases as the junction temperature increases. The wide operating temperature range (-40°C to +85°C) indicates stable performance across environmental extremes, though brightness at the high end will be reduced compared to 25°C.
• Spectral Distribution: The provided Peak (λP) and Dominant (λd) wavelengths, along with the Spectral Half-Width (Δλ), define the emission spectrum. The Amber LED has a broader spectrum (Δλ=17nm) centered at ~611nm, while the Yellow Green is narrower (Δλ=11nm) and centered at ~575nm.

5. Mechanical & Package Information

5.1 Outline Dimensions

The LED uses a standard T-1 3/4 radial leaded package. Key dimensional notes include:

• All dimensions are in millimeters (with inch equivalents).
• Standard tolerance is ±0.25mm unless specified otherwise.
• The maximum protrusion of resin under the flange is 1.0mm.
• Lead spacing is measured where the leads exit the package body, which is critical for PCB layout.

The package features a diffused white lens which helps scatter light, creating the wide 80-degree viewing angle and a softer, less glaring appearance compared to a clear lens.

5.2 Polarity Identification

The LTL30EKFGJ is a common anode device. This means the anode (positive lead) is shared internally, and each color cathode (negative lead) is separate. The longer lead is typically the common anode. Always verify polarity using the datasheet diagram before soldering to prevent reverse connection damage.

6. Soldering & Assembly Guidelines

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

6.1 Lead Forming & PCB Assembly

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

6.2 Soldering Process

Maintain a minimum clearance of 2mm between the solder point and the base of the lens. Do not immerse the lens in solder.

• Hand Soldering (Iron):
  • Maximum Temperature: 350°C.
  • Maximum Time: 3 seconds per lead.
  • Limit to one soldering cycle per joint.
• Wave Soldering:
  • Pre-heat Temperature: Max. 100°C.
  • Pre-heat Time: Max. 60 seconds.
  • Solder Wave Temperature: Max. 260°C.
  • Soldering Time: Max. 5 seconds.
  • Ensure the LED is positioned so the solder wave does not come closer than 2mm to the lens base.
• Critical Warning: Excessive temperature or time can melt the epoxy lens, cause internal wire bond failure, or degrade the semiconductor material. IR reflow soldering is not suitable for this through-hole package type.

6.3 Storage & Cleaning

• Storage: Store in 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 longer storage outside original packaging, use a sealed container with desiccant or a nitrogen desiccator.
• Cleaning: If necessary, clean only with alcohol-based solvents like isopropyl alcohol (IPA). Avoid harsh or abrasive cleaners.

7. Packaging & Ordering Information

7.1 Packaging Specification

The product is supplied in industry-standard packaging for automated or manual handling:

• Basic Unit: 500, 200, or 100 pieces per packing bag.
• Inner Carton: Contains 10 packing bags, totaling 5,000 pieces.
• Outer Carton (Shipping Case): Contains 8 inner cartons, totaling 40,000 pieces.
• A note indicates that within a shipping lot, only the final pack may be a non-full quantity.

7.2 Model Number Interpretation

The part number LTL30EKFGJ follows a manufacturer-specific coding system likely indicating package type (T-1 3/4), color (Amber/Yellow Green), and intensity bin. For precise ordering, the required Bin Codes for Luminous Intensity and (for Yellow Green) Dominant Wavelength must be specified alongside the base part number.

8. Application Design Considerations

8.1 Drive Circuit Design

LEDs are current-driven devices. The most critical design rule is to use a series current-limiting resistor for each LED or each parallel string of LEDs.

• Recommended Circuit (Circuit A): A voltage source (Vcc), a series resistor (R), and the LED. The resistor value is calculated as: R = (Vcc - VF) / IF, where VF is the LED forward voltage (use max value of 2.4V for design margin) and IF is the desired forward current (e.g., 20mA).
• Circuit to Avoid (Circuit B): Connecting multiple LEDs directly in parallel with a single shared resistor. Small variances in the I-V characteristics (VF) between individual LEDs will cause current imbalance, leading to significant differences in brightness and potential over-current failure of the LED with the lowest VF.

8.2 Electrostatic Discharge (ESD) Protection

The LED is sensitive to electrostatic discharge. Implement the following precautions during handling and assembly:

• Operators should wear grounded wrist straps or anti-static gloves.
• All workstations, tools, and equipment must be properly grounded.
• Use ionizers to neutralize static charge that may accumulate on the plastic lens.
• Ensure personnel are trained in ESD-safe handling procedures.

8.3 Thermal Management

While the power dissipation is low (80mW max), maintaining the LED within its operating temperature range is vital for longevity and stable light output. Ensure adequate airflow in the end-product enclosure, especially if multiple LEDs are used in close proximity or if the ambient temperature is high.

9. Technical Comparison & Selection Guidance

The LTL30EKFGJ offers a specific combination of attributes. When selecting an indicator LED, consider these points relative to alternatives:

• vs. Smaller SMD LEDs: Through-hole LEDs like this one are generally easier for prototyping, manual assembly, and repair. They often have higher single-point brightness and wider viewing angles than comparably sized SMDs but require PCB drilling and occupy more board space on both sides.
• vs. Clear Lens LEDs: The diffused white lens provides a wider, softer viewing angle and hides the internal die, offering a more uniform "glow" ideal for panel indicators. Clear lens LEDs have a more focused beam and higher axial intensity but can appear as a bright point source.
• Color Choice: Amber (605nm) is highly visible and often used for warnings or alerts. Yellow Green (572nm) is near the peak sensitivity of the human eye (555nm), making it appear very bright at lower power, ideal for general status indicators.
• Current Drive: Its 30mA maximum DC current is standard for 5mm LEDs. For ultra-low-power applications, similar devices rated for 10-20mA might be more appropriate.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 Can I drive this LED directly from a 5V or 3.3V logic pin?

No, not without a current-limiting resistor. Connecting it directly would attempt to pull far more than 30mA through the LED and the microcontroller pin, likely damaging both. Always use a series resistor calculated for your supply voltage.

10.2 Why is the maximum luminous intensity given as a range (e.g., 110-240 mcd for Amber)?

This reflects the binning system. The absolute maximum from the datasheet is 240 mcd, but actual shipped parts will fall into specific intensity bins (F, G, H, J, K). You must specify the required bin to guarantee a minimum brightness level for your design.

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

Peak Wavelength (λP) is the single wavelength at which the emitted optical power is highest. Dominant Wavelength (λd) is the single wavelength of a pure monochromatic light that would appear to have the same color to the human eye. λd is more relevant for color indication applications, while λP is more relevant for optical sensing.

10.4 Can I use this LED outdoors?

The datasheet states it is suitable for "indoor and outdoor sign" applications. Its operating temperature range (-40°C to +85°C) supports this. However, for prolonged outdoor use, consider additional protection from UV radiation and moisture ingress, which may not be fully specified for this standard package.

11. Practical Application Examples

11.1 Power Indicator on a Consumer Appliance

Scenario: Designing a "Power On" indicator for a device powered by a 12V DC wall adapter.
Design: Use an Amber LED for a warm, clear indication. Target 15mA for good brightness and longevity.
Calculation: R = (Vcc - VF) / IF = (12V - 2.4V) / 0.015A = 640 Ohms. Use the nearest standard value, 680 Ohms. Re-calculated current: IF = (12V - 2.1V) / 680Ω ≈ 14.6mA (safe and within spec).
Implementation: Place the 680Ω resistor in series with the LED anode, connecting to the 12V rail. The LED cathode connects to ground.

11.2 Multi-LED Status Array

Scenario: A panel with 5 LEDs showing different system states (e.g., Ready, Active, Error, etc.). Color consistency is important.
Design: Use Yellow Green LEDs for all indicators. Specify a tight Dominant Wavelength bin (e.g., H07) and a specific Luminous Intensity bin (e.g., E or F) when ordering. Drive each LED with its own dedicated current-limiting resistor from a common voltage rail to ensure uniform brightness regardless of small VF variations.

12. Operating Principle

The LED operates on the principle of electroluminescence in a semiconductor diode. When a forward voltage exceeding the diode's built-in potential (roughly 2.1V for these devices) is applied, electrons and holes are injected into the active region from the n-type and p-type materials, respectively. These charge carriers recombine, releasing energy in the form of photons (light). The specific wavelength (color) of the emitted light is determined by the bandgap energy of the semiconductor material used in the active region. The diffused epoxy lens surrounding the semiconductor die serves to extract the light, shape the beam, and protect the delicate internal structure.

13. Technology Trends

While through-hole LEDs remain vital for legacy designs, prototyping, and certain applications requiring high single-point brightness or ease of service, the industry trend is strongly towards Surface-Mount Device (SMD) packages. SMD LEDs offer significant advantages in automated assembly, board space savings, and lower profile. However, through-hole components like the LTL30EKFGJ continue to be relevant due to their mechanical robustness, excellent heat dissipation via leads, and simplicity for low-volume or educational projects. Advances in materials are continually improving the efficiency, longevity, and color consistency of all LED types, including through-hole variants.